Vade-mecum.pdf

CEMENT

Cement Process Engineering Vade-Mecum

Version September 2010

LAFARGE CEMENT DPC Direction des Performances Cimentières

www.lo.lafarge.com

.

Cement Process Engineering Vade-Mecum © Lafarge SA, 1990-2010. All rights of reproduction, representation, adaptation and translation relating to this report belong to Lafarge SA. Lafarge SA reserves the right to exploit this report or not and to freely distribute it to all of its current and future subsidiaries worldwide in any form, whether paper, electronic or digital, including via internet and/or intranet. This report along with its content is of a confidential nature. In particular, it may not be reproduced, copied, transmitted, published, divulged and/or appropriated in whole or in part for personal use or for use by a third party without prior consent from the Cement Division’s Direction des Performances Cimentières (DPC), except for reproduction by or for affiliated Lafarge companies.

CEMENT PROCESS ENGINEERING VADE-MECUM

Foreword This latest version of Vade-mecum has now become a true Lafarge Cement Division document, having been produced by worldwide collaboration of all Technical Centres and DPC, with the involvement of several departments: Process, Quality, Refractory, Industrial Ecology and Industrial Knowledge. Existing chapters have been extensively updated and several new chapters added. The first version of the booklet was produced in 1990 by CTS. Although it was produced by a single Technical Centre it has become so popular that over the years it has become the accepted reference for the whole Cement Division. “Vade-mecum” is a Latin expression that means “Something that goes with me”. The purpose of this handbook is to provide process engineers with a tool to overcome technical problems and lead to good process recommendations. It is not intended to deeply explain the theory, but only to give the main points, reminders, rules of thumb, equations and reference values. Many documents “How to”, “Process Tools”, Technical Agenda Studies, etc are already available in the Cement Portal going into details of specific subjects and these should be consulted for a deeper understanding. A list of relevant references is given at the end of each chapter. The booklet will only be made available on the Cement Portal (and EASI Plus!) to allow updating and addition of new chapters on a more frequent basis than the hardcopy booklet permitted. In the event a hardcopy is required each chapter can be printed in A5 booklet format and stored in a ring binder to allow replacement of old chapters following any updates, please only print if absolutely necessary. As you know, sharing of experience and knowledge is key to the success of Lafarge and you are actively encouraged to participate in the further development of this already excellent tool, so please feel free to send your ideas or suggestions or challenge some of its content to your Technical Centre contact, or to the Process Network via the COP discussion forums on the Cement Portal or email directly to DPC. Have a sound utilization of this booklet and improve plant performances.

Colin Paxton

Jacques Denizeau

Senior Process Manager – DPC

Director Process & Automation – DPC

email: [email protected]

email: [email protected]

© Copyright 2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM

Table of Contents 1-1 1-2 2-1 2-2 3-1 3-2 3-3 4 5 6 7 8 9-1 9-2 9-3 9-4

Ball Milling Including Separators Vertical Raw Mill Combustion & Fuels Alternative Fuels Kiln Heat & Mass Balance Volatile Cycles & Control Kiln Systems Product Quality & Development Environment Fluid Flow Process Control Refractories Mathematics Statistics Thermodynamic & Chemical Data Unit Conversion

© Copyright 2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-1 – BALL MILLING INCLUDING SEPARATORS

1-1. Ball Milling including Separators

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

BALL MILLING incl. SEPARATORS – Page 1/25 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-1 – BALL MILLING INCLUDING SEPARATORS

Table of Contents 1.

Ball Mill General ............................................................................... 3 1.1. 1.2. 1.3. 1.4. 1.5. 1.6. 1.7. 1.8.

2.

Ball Charge and Internals ................................................................ 6 2.1. 2.2. 2.3. 2.4.

3.

BB10 Test ......................................................................................................13 Bond Test.......................................................................................................13 Hardgrove Test ..............................................................................................14 Parameters Affecting the Clinker Grindability................................................14

Mill Performance Benchmarking .................................................. 15 6.1. 6.2.

7.

Absorbed Power of a Mill...............................................................................11 Charles, Bond, Kick & Rittinger Laws............................................................12

Grindability Measurement ............................................................. 13 5.1. 5.2. 5.3. 5.4.

6.

Recommended volume loading .......................................................................8 Ball charge design for new mill without pre-existing experience.....................8 Polysius Design ...............................................................................................9 Slegten Model ................................................................................................10 Fineness in Finish Mills:.................................................................................11

Grinding Laws ................................................................................ 11 4.1. 4.2.

5.

Largest Ball ......................................................................................................6 Grinding Balls Data..........................................................................................6 Other internals .................................................................................................7 Mill Internal Inspection Sheet...........................................................................7

Ball Charge Design (Finish Mill) ..................................................... 8 3.1. 3.2. 3.3. 3.4. 3.5.

4.

Comparison of Grinding Equipment ................................................................3 Mill Design .......................................................................................................3 Percent loading of mill .....................................................................................3 Mill Critical Speed ............................................................................................4 Retention Time ................................................................................................5 Mill Throughput ................................................................................................5 Required air velocities for mill ventilation ........................................................5 Optimum filling ratio: ........................................................................................5

Performance Indicator Finish Mills Absorbed (PIFMA) .................................15 Benchmarking Ball Mills with Bond Wi ..........................................................16

Separator ........................................................................................ 17 7.1. 7.2. 7.3. 7.4.

Circulating Load (CL).....................................................................................17 Tromp Curve ..................................................................................................17 Indicators for Cement Milling and Typical Values .........................................19 Recommended Sizing for a HES...................................................................20

8.

Grinding Aid ................................................................................... 21

9.

Other Data....................................................................................... 22 9.1. 9.2. 9.3.

Sieve Sizes ....................................................................................................22 Bulk Densities ................................................................................................22 Residue Conversion Chart ............................................................................23

10. References...................................................................................... 24

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BALL MILLING incl. SEPARATORS – Page 2/25 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-1 – BALL MILLING INCLUDING SEPARATORS

1.

Ball Mill General

1.1.

Comparison of Grinding Equipment

The priority study cement grinding shop compares the full shop power consumption using the 3 main types of technology, see the table below:

Power Consumption kWh/t Relative Consumption

Closed Circuit Ball Mill 40.2 1.0

Vertical Mill

Roller Press *(Integral Grinding) 26.9 0.67

27.4 0.68

* Integral grinding is not used for cement grinding due mainly to quality issues with the narrow particle size distribution of the product. Hence semi-integral grinding using a closed circuit roller press and closed circuit ball is more common with a circuit power consumption of around 30 kWh/t.

1.2.

Mill Design

General L/D ratio

• Raw mills: 1.5 < L/D < 3.2 • Finish / cement mills: 2.5 < L/D < 3.0 L/D vs specific power consumption for different volume loads The optimum specific energy and the highest output for cement grinding is reached with an L/D ratio of 2,5 to 3.

Length of first Compartments relative to total mill length

• Raw mills: First compartment length equals 35 – 45% of total mill effective length. • Cement mill: First compartment length equals 30 – 35% of total mill effective length. • When L/D>1.5, classifying liners might be used. • The lower the L/D, the higher the circulating load needs to be (see below).

1.3.

Percent loading of mill 2π αr 2 − r sin α (h − r ) • % volume load = 360 πr 2 where: ƒ r is the radius ƒ h is the free height

ƒ

α (degrees) = arccos

0.9 h/d 0.8 0.7 0.6

h−r r

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

0.5 0

10

20

30

40

50%

% volume load

BALL MILLING incl. SEPARATORS – Page 3/25 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-1 – BALL MILLING INCLUDING SEPARATORS

Rules of thumb

• % vol. Load = 111.87 – 123.98 (h/d), 25 – 50%: error max 0.6%. • It is estimated that material increases the actual ball filling ratio by about 2%. • Another method (quick but not as accurate) consists in counting the number of visible shell liner plates (n) and to divide by the total number of shell liner plates per circumference (N): Angle x 360 / N.

α

=n

Values of angle h/d ratio in relation to the ball load (% filling degree) Ball load (%) 20 21 22 23 24 25 26 27 28 29 30

1.4.

h/d .7459 .737 .7281 .7193 .7106 .702 .6926 .685 .6765 .6682 .6598

n/N .667

Ball load (%) 31 32 33 34 35 36 37 38 39 40 41 42

.653 .639 .625 .611 .601

h/d .6516 .6434 .6352 .627 .6189 .6109 .6028 .5948 .5868 .5789 .5709 .563

n/N .590 .580 .569 .558 .549 .539

Mill Critical Speed •

C

C = mω 2 r =

m

Gω 2 r g

where: ƒ G = Weight of grinding ball in kg

P r

ƒ ω = angular velocity of mill tube (rad/sec) ƒ n = rev per minute ƒ C = centrifugal force kg

Ž G

•

P = G * sin ∂ (P is the resulting force of gravity)

• To maintain the ball in this position on the mill wall, it is necessary that C ≥ P. • Mill critical speed: nc =

60 2 g 4 π2 r

=

42.3 D

with D in meters

% Critical speed:

• Practically, mill speed between 68 and 82% of critical speed. • % critical speed is the mill actual speed in RPM divided by nc. Example: 3.98 meter mill with rotational speed of 15.6 rpm then nc = 21.2, % critical speed = 73.6 %.

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BALL MILLING incl. SEPARATORS – Page 4/25 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-1 – BALL MILLING INCLUDING SEPARATORS

1.5.

Retention Time

Rules of thumb:

• Retention time in mill:

Open circuits: ~ 12 min Closed circuits: ~ 5 min

• Feed is pushing the material through the mill, If mill throughput increases: retention time decreases: C < 12 where: C is the ball charge weight, M is the material weight 8< M Fluoroscein Tracer test:

• 2g/t of mill production. Prepare the fluoroscein with 800-ml alcohol and impregnate 2 kg of mill feed material (in a plastic bag).

• Put the material at mill inlet, start the time and sample every 30 s during 30 min. (others use salt).

1.6.

Mill Throughput

• Using elevator power and after calibrating we have:

A=

(kW − kW0 ). 3600 .η 9,81. H

Where:

ƒ A ƒ kW ƒ kW0 ƒ η ƒ H

1.7.

=

Material flow (mtph)

=

Actual elevator power

=

Elevator power empty

=

Elevator efficiency

=

Inter axis elevator height

Required air velocities for mill ventilation

Rules of thumb

• Recommended 1.5 m/s above the ball charge: -

inside the trunnion: 22-25 m/s. partitions: 8-14 m/s (<20 m/s). hood: <5 m/s to prevent dust from being sucked up (dust pick-up is proportional to speed^2). dropout box: <2 m/s.

• 0.3-0.5 Nm3/kg cement 0.6-0.8 Nm3/kg raw mix (depending upon drying needs)

• Wet bulb temperature should be at least 25°C higher then dew point temperature. • False air at mill outlet is usually >25%. Consider high false air volume in heat balance and in mill ventilation design.

1.8.

Optimum filling ratio:

• U= (volume of powder in the mill)/ (volume of voids in the charge): between 60% and 110%, optimum around 90%.

• In practical terms, material level should equal ball level in the first compartment • In practical terms, material level should be higher than ball level in the second compartment • The expansion of the ball charge due to the material in between would not exceed 3% in an optimised mill (measurement of the ball charge level of the empty and the filled mill)

• The material filling in the first compartment can be adjusted with flow control devices in modern diaphragms. (scoops, flaps)

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BALL MILLING incl. SEPARATORS – Page 5/25 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-1 – BALL MILLING INCLUDING SEPARATORS

2.

Ball Charge and Internals

2.1.

Largest Ball

Bond Formula

•

d KMAX

-

d Wi ρ = 20.17 20 .3 K Ψ. Du

-

where: d KMAX is the largest ball diameter (mm) -

d 20 is the sieve dimension (µ)

K is a constant (350 for a dry mill open or close circuit, 300 for wet) ρ is the specific mass of material (g/cm3)

-

Wi is the Bond work index (kWh/t) Du is the mill inside diameter (m)

Ψ is the ratio between the actual / critical speed (%)

with 20% retained

B = 24 d 80 (Other formula exist that result in value differences of ± 5%) B = ball dimension (mm) d 80 is the sieve with 80% passing

2.2.

Optimum Ball Diameter (mm)

Grinding Ball vs Clinker Size

Quick evaluation • For clinker:

100

10 1

.1

10

100

Clinker Size d80

Grinding Balls Data

Grinding Ball dimensions Weight Surface Number of balls per Diameter (g) (cm2) metric tons mm inch 4,001.153 314.159 250 100.00 ± 4" 2,916.841 254.469 343 90.00 ±3½" 2,048.590 201.062 488 80.00 1,826.658 186.265 548 77.00 ±3½" 1,372.396 153.938 729 70.00 1,048.878 128.680 954 64.00 ±2½" 864.249 113.097 1,157 60.00 500.144 78.540 2,000 50.00 ±2" 256.074 50.265 3,905 40.00 219.551 45.365 4,555 38.00 ±1½" 171.549 38.485 5,830 35.00 128.061 31.669 7,809 31.75 ±1¼" 108.031 28.274 9,257 30.00 62.518 19.635 15,996 25.00 ±1" 48.682 16.619 20,542 23.00 43.895 15.511 22,782 22.22 =7/8" 32.009 12.566 31,242 20.00 ±3/4" 19.658 9.079 50,870 17.00 ±5.8" (Unit weight and specific surface of MAGOTTEAUX grinding media)

Weight of 1 m3 of balls (kg) 4560 4590 4620 4640 4660 4708 4760

4850 4894

4948 4989

Specific surface 2 (m / mt) 7.854 8.728 9.812 10.207 11.222 12.276 13.085 15,708 19.628 20.664 22.437 24.730 26.173 31.408 34.139 35.337 39.259 46.185

Quick calculation:

•

Ball diameter (mm) =

•

Specific surface of balls of diameter =

3

250 P

(P = weight in g)

785 2 m / mt d

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(d = diameter in mm)

BALL MILLING incl. SEPARATORS – Page 6/25 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-1 – BALL MILLING INCLUDING SEPARATORS

Wear rates: In the 1st compartment the wear rate is correlated with the average ball weight (positive correlation), whereas in the 2nd compartment it is correlated with the ball charge surface area (positive correlation as well). Below are general guidelines for raw as well as cement grinding wear rates: Raw grinding • Raw mix with free silica (quartz) content <5%: 30-60 g/t • Raw mix with free silica (quartz) content >5%: 50-100 g/t Cement • CEM I, clinker >90%, 300 m2/kg : 30-60 g/t • CEM I, clinker >90%, 450 m2/kg: 60-100 g/t • CEM III, slag 70%, 300 m2/kg: 60-120 g/t • CEM III, slag 70%, 450 m2/kg: 120-200 g/t • Suppliers would typically guarantee <40 g/t for CEM I Bulk density for ball load (Coarse to medium ball size distribution): • Chamber 1: 4.3 – 4.5 t/m3 • Chamber 2: 4.5 – 4.65 t/m3 • Single Chamber mill: 4.5 – 4.55 t/m3

2.3.

Other internals

Partitions • Total slot area: 10 to 20 cm²/tph production: Slot Size Central Part Discharge Part FM 7 mm ± 1 mm 9 mm ± 1 mm RM 10 mm ± 1 mm 12 mm ± 1 mm

Max opening: ½ min ball size

Liners • Liners replaced when 60% of their effective lifting height has worn away: Reduction 8 to 10 % production reference points to measure lifting height are the lowest point on the liner to the highest release point (contact points between grinding ball and liner plate) • American Lorrain pattern: diameter (ft)*2=# bolt holes/row, 18.8” centre to centre. • DIN pattern: diameter (m)*10= # bolt holes/row, 31.4 cm centre to centre. • Classifying liners if L/D>1.5 and volume load<35%. • Without classifying liners, keep a maximum of 3-4 ball sizes.

2.4.

Mill Internal Inspection Sheet

Shell Liner Thickness Shell Liner Lifter Thickness Shell Liner Remarks – crack, gaps…. Inlet Head Liner Thickness Inlet Head Liner Remarks Inlet Opening Remarks Height Liner, to Balls – Average Width Across Balls – Average Calculated Percent Fill – mill ran out Build up on water injection lance Presence of material nibs

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

Ball Charge Remarks – sizes, shape, contamination, breakages Ball Coating Remarks Ball Classification Remarks Discharge Grate Slot Size-Average Discharge Grate Slot Size-Maximum Discharge Grate Metal Thickness – gaps etc. Discharge Grate Percent Blinded Discharge/Centre Screen Percent Blinded Height of Material relative to media Calculated Percent Fill – mill crash stopped

BALL MILLING incl. SEPARATORS – Page 7/25 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-1 – BALL MILLING INCLUDING SEPARATORS

3.

Ball Charge Design (Finish Mill)

3.1.

Recommended volume loading

(see “How to Optimise Ball Charge”) Recommended Volume Loading 1st Compartment 2nd Compartment 3rd Compartment 1 Minimum kWh/t 26 – 28% 28 – 30% 28 – 30% Maximum Production 32 – 34 % 34 – 36% 34 – 36% (Ball level in the trunnion should not be higher than 50 to 75 mm.)

3.2.

Ball charge design for new mill without pre-existing experience

Closed circuit finish mill Chamber 1 Coarse charge %

Fine charge %

90

40

21

80 70 60

29 19 12

38 25 16

Average ball weight (kg/ball)

1.83

1.63

Ball size (mm)

Ball size (mm) 40 (transition zone) 30 25 20 17 Average ball weight (g/ball)

Chamber 2 Coarse charge %

Fine charge %

10 25 25 20 20

15 15 30 40

47

34

Specific surface 32 37 (m2/t) Note: With high circulating loads, as with oversized separators the coarser grading in the 2nd chamber is more suitable to help maintain charge permeability 1

The recommended volume loading for minimum kWh/t is based on an acceptable compromise with production. For minimum kWh/t the volume loading can be as low as 22% in the second compartment. Due to risk of breakage the minimum volume loading in first compartment shall not underpass 25%.

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BALL MILLING incl. SEPARATORS – Page 8/25 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-1 – BALL MILLING INCLUDING SEPARATORS

Open circuit finish mills

Ball size (mm) 90 80 70 60 Average ball weight (kg/ball)

Chamber 1 Coarse charge % 40 29 19 12

Fine charge % 21 38 25 16

Chamber 2

1.83

1.63

Ball size (mm)

%

30 25 20 17 Average ball weight (g/ball)

10 10 20 60

Specific surface (m2/t)

30 39

Raw mills Chamber 1 Ball size (mm)

%

Ball size (mm)

90 80 70 60 Average ball weight (kg/ball)

40 29 19 12

60 50 40 30 Average ball weight (g/ball)

1.83

Specific surface (m2/t)

Chamber 2 Coarse charge % 20 30 30 20

Fine charge % 30 30 40

260

186

18

21

Note: Up to 50% 90 mm are used in some mills

3.3. •

•

•

Polysius Design

As a rule of thumb, it suits raw mills and especially mono-chambers very well, especially if no classifying liners are used.

⎡ D ⎤ ln ⎢ 9.6 ⎥⎦ D = 9.6 e −013.x ⇔ x = ⎣ − 0.13 where: D = Ø ball (cm) x = effective mill length (m) Process step-by-step, calculating each effective length starting from the input and with the largest ball: 1. Calculate effective lengths and the ball sizes you plan to use. 2. Double the first effective length which is both the first interval width and the first cumulative length. 3. Calculate each succeeding interval width by taking the effective length and subtract the preceding cumulative length and doubling it. Add this value to the previous cumulative length to get the new one. 4. If an interval overlaps with the partition divide the interval at the point of overlap. The excess is carried over to the next compartment. At the end of the mill, the interval is truncated at the point of overlap. 5. Once the intervals have been adjusted for compartment lengths as described in step (4), divide the adjusted interval by compartment length and multiply by 100. This is the percent weight for each size to be used in the compartment.

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BALL MILLING incl. SEPARATORS – Page 9/25 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-1 – BALL MILLING INCLUDING SEPARATORS

Slegten Model •

Compatible mostly with classifying linings in the second compartment.

First Compartment – Crushing Same number (n) of balls in each size range.80, 70 and 60 mm Ø and then add some 90 mm Ø to deal with oversize clinker. This equilibrium charge will not change as you add 90 mm Ø make-up balls to maintain volume load. Ø Ball (mm) % of Weight (x) % of Weight Number/ 10 t of Charge 90 100-5x 20.0 670 80 2*4x 38.4 1820 70 1.6x 25.6 1820 60 X 16.0 1820 - x = is taken to be the number of balls in the last size. • In recent years, Slegten has favoured a 3-ball size distribution in first compartments over a 4- ball size as shown in table above.

•

Transition Zone • This is the start of the second compartment and its job is to crush any oversize that penetrated the diaphragm • The design for this area is to use "n" balls of 50 and 40 mm. Ø Ball (mm) Number/ 10 t of Charge 50 1820 40 1820 •

The largest ball size used in this transition zone can be identical to the smallest ball size used in the first compartment.

Second Compartment – Fine Grinding • The envelope curve for the balls smaller than 40 mm follows the following formula: where: • D = 3.3e −010.x D = Ø ball (cm) x = distance from transition zone finish (m) • The 30 mm balls start at the completion of the transition zone and the exponential curve follows. Rule of thumb: • The smallest ball size should, as a minimum, be at least twice the width of the slots in the grates (ex. ≥16 mm balls if slots are ≤8 mm wide). For this reason, it is generally recommended to use ¾” (19 mm) balls as the smallest size in Finish mills. 5/8” balls are fine when the grates are new but often become problematic as the grate slots enlarge. Example: Comparison Slegten & Polysius 1st compartment useful length = 3.81 m, 2nd compartment useful length = 7.66 m Using an average ball weight of 1.65 kg per ball and 3 ball sizes in the first compartment for the Slegten model. Ball size and % Polysius Slegten compartment load design design 1st compartment 3 ½” 31.0% 32.1% 3” 31.2% 43.1% 2 ½” 37.8% 24.8 % Transition zone 2nd compartment 2” 2.31% 7.67% 1 ½” 23.73% 2.94% 1 ¼” 34.05% 10.08% 1” 2.57% 48.18% ¾” 37.34% 31.13% 5/8” (Some)1 A limited amount of 5/8” balls should theoretically be added but the designer decided to use ¾” as the smallest ball size.

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BALL MILLING incl. SEPARATORS – Page 10/25 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-1 – BALL MILLING INCLUDING SEPARATORS

3.4.

Fineness in Finish Mills:

In the first compartment before intermediate diaphragm • 95% passing of 2.365 mm (2360 μm or 8 mesh) for the material leaving the first compartment • Particle size distribution recommended on other sieves: - 86 – 92 % passing 1.0 mm (1000 μm or 18 mesh) - 80 – 90 % passing 0.6 mm (595 μm or 30 mesh) - 75 – 85 % passing 0.5 mm (500 μm or 35 mesh) In the second compartment before discharge diaphragm • 95% passing 0.5 mm (500 μm or 35 mesh) • 70 - 80 % passing 0.2 mm (212 μm or 70 mesh)

4.

Grinding Laws

4.1. • •

Absorbed Power of a Mill

Only 5-10 % of the energy is used for grinding, 90% is wasted into heat, wear, noise… With similar ball charge gradation and similar liners' lifting effect, the absorbed power is related to: Tonnage of balls Mill rpm % volume load Mill diameter

Slegten formula

•

⎛ rpm ⎞ ⎟ P = W * ⎜⎜ ⎟ ⎝ Vcr ⎠

1.27

* K j * K Fr

and

W=

π 4

* Fr 2 * L * J * d

where: P : the motor absorbed power (kW) J : the ratio between the apparent ball volume and the internal volume W : the weight of the load (T) - rpm: is mill speed (rpm) Fr : internal diameter (inside liners) (m) d is the apparent density of load (t/m3) #1 comp : d = 4.5 #2 comp : d = 4.65, if fine ball size distribution (average ball weight < 40 g) d = 4.6, if coarser ball size distribution (average ball weight > 40 g) Average : d = 4.6 -

⎛ 42.3 Vcr is the critical speed inside liners= ⎜ ⎜ F r ⎝

-

K j = 1.36 − 1.2 J , K Fr = C.Fr

-

•

⎞ ⎟ , L : the useful length of mill (m) ⎟ ⎠

0.379

K Fr is the influence of the location of the center of gravity for the moving ball charge vs. the mill center (C is a constant depending on the material and the liners). C= 11.262 for Clinker mill closed circuit with Slegten equipment 10.7 for clinker + slag, 12.16 for raw mix, 10.1 for slurry

⎛ rpm ⎞ ⎟ P = L * ⎜⎜ ⎟ V ⎝ cr ⎠

1.27

* J* K j *

π 4

* Fr2.379 * d * C

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BALL MILLING incl. SEPARATORS – Page 11/25 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-1 – BALL MILLING INCLUDING SEPARATORS

Simplified formula

Fr ⎡ RPM ⎤ 100 P =T *⎢ *Kj * * 9.5 ⎥* 1.366 ⎣ Vcr ⎦ 75

•

Kj Function of Volume Load Volume load Kj 40% 30% 20%

0.9 1 1.1

Rules of Thumb • One metric tonne of balls increases the mill power draw by 10 kW. • Usually, 8 to 12 kWh/t is absorbed in the first compartment for clinker grinding (approximately 1/3 of the mill power)

4.2.

Charles, Bond, Kick & Rittinger Laws

General Law: Charles • dW = cx −n dx -

If W = Comminution work, particles (initial, final)

Value of n Energy Law Rittinger Kick Bond

Value of n: 2 1 1.5

x = Size of

Applies well over range of: 10 – 1000 μm

Normalized Blaine fineness equation • Fineness equation, generally accepted within Lafarge:

⎡ SA ⎤ W2 = W1 ⎢ 2 ⎥ ⎣ SA 1 ⎦ -

n

n = 1.3 for high efficiency separator (HES) circuit, n = 1.4 for second generation separators, n = 1.5 for Sturtevant separators, bearing in mind that 16’ and 18’ Sturtevant separators are more efficient than the larger 20’ and 22’ Sturtevant. n = 1.6 for open circuit mills W1 and W2,are the initial and resulting specific power consumption kWh/t, W is inversely proportional to production rates. SA1 and SA2 are the initial and final product surface areas m2/kg 0.43( SA1 − SA2 ) / 1000

•

Proposed by Polysius: C 2 = C1 * e

•

where C2 and C1 are production capacities Rene’s Study: +1% passing at 10µm: +10.8 SSB [m²/kg]

Rules of thumb Raw material: 10-16 kWh/t (mill motor) target fineness: passing 200µm>99%, passing 90µm>88% depending upon burnability of raw mix) • Clinker: 45 ± 15 kWh/t at 350 m2/kg (mill motor). For a pure cement (95% clinker) at <400 m2/kg, the mill motor consumption should be <40 kWh/t.

•

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BALL MILLING incl. SEPARATORS – Page 12/25 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-1 – BALL MILLING INCLUDING SEPARATORS

5.

Grindability Measurement

5.1. BB10 Test Idea:

Correlate the number of revolutions of a lab mill for a given fineness with the industrial energy to obtain the same fineness. The material is crushed to everything passing 3.15 mm. The number of mill revolutions is measured to obtain a given fineness. Revolutions are converted to industrial power consumption. Lab Mill Characteristics: Diameter: 40 cm Length: 12 cm Speed: 55 rpm Ball volume load: 14 % Ball weight: 10 kg

Material load: 1kg Balls: 20-25 mm : 2.5 kg 20-35 mm : 3 kg 50 mm : 4.5 kg

Lafarge Data

•

60 clinkers. Typical results are 48-60 kWh/t 3500 m2/kg. BB10 kWh/t Minimum Average Maximum

for 250 m2/kg kWh/t 21 29.2 43

for 300 m2/kg kWh/t 30 39.8 56

for 350 m2/kg kWh/t 39 51.8 68

for 400 m2/kg kWh/t 49 65.3 83

Remark: An average CEM I 32,5 at 300 m²/t can be ground with 28kWh/t related to the mill main drive. The additional energy for finer grinding should not exceed the Normalized Blaine fineness equation described in chapter 4.2.

5.2.

Bond Test

Lab Mill Characteristics Diameter: 30.5 cm Length: 30.5 cm Ball weight: 20 kg Material quantity: 700 cm3 Speed: 70 rpm

Formula

Wi =

44.5 ⎛ 10 10 − d p 100 0.23 • P 0.82 * ⎜⎜ ⎜ d p 80 d f 80 ⎝

⎞ ⎟ ⎟⎟ ⎠

dp100 is the sieve with 100% passing feed material dp80 80% feed material df80 80% finish material P is the production (g/rev of mill) of product at the level the circulating load is requested. Wi is the Bond work index kWh/short ton.

•

Developed to predict energy requirements of 2.44m diameter, wet, closed circuit, ball mill at a fineness of either 65 mesh (220 µm) or 100 mesh(150 µm).

•

Pre-crush feed to #6 (3.35 mm). Maintain 700g sample in test mill. Turn mill 100-150 rev.

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BALL MILLING incl. SEPARATORS – Page 13/25 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-1 – BALL MILLING INCLUDING SEPARATORS

•

Remove undersize (dp100 – 65 or 100 mesh) and replace with fresh feed (300 – 400 g). 1st cycle is now completed. Repeat procedure until steady state is reached. Typically 6-8 cycles so that 200 g are removed at each cycle, which equals 250% circulating load or 30% of “P”.

•

The Work index expresses the specific net energy needed to grind a material from indefinite feed size to dp80 =100 µm

•

Wi for Raw materials for cement plants are usually in the range of 8 – 16 kWh/st

Typical Values for Wi for common materials:

Wi Clinker: Limestone Shale Slag Sand stone Silica sand Coal Clay Gypsum Kiln feed

kWh/st*

ρ (g/cm3)

13.49 10.18 16.40 15.76 11.53 16.46 11.37 7.10 8.16 10.57

3.09 2.68 2.58 2.93 2.68 2.65 1.63 2.23 2.69 2.67

*Clearly

the Wi can vary significantly from these figures depending upon the nature of the materials and material testing is necessary for each particular case when assessing a mill.

5.3.

Hardgrove Test

The Hardgrove test was originally developed for determination of coal grindability, using a laboratory scale ring ball mill. Feed size is prepared in the range 600 – 1180 µm. The mill is charged with 50g of feed and operated for 50 revolutions. The result is calculated from the proportion of material passing 75µm. The figure is meant to compare the grindability with a standard American coal with an index of 100. Bond gave the following equation to convert HGI into a Bond Wi:

Wi =

435 HGI 0.91

Other similar relationships can be found in the literature. Ranges of HGI found in cement plant raw materials are given below: Material Clay Coal Limestone Shale Silica Sand

HGI* 130 – 160 35 – 90 60 – 120 60 - 170 30 - 100

*Clearly

the HGI can vary significantly from these figures depending upon the nature of the materials and material testing is necessary for each particular case when assessing a mill.

5.4. Parameters Affecting the Clinker Grindability 1 point increase of Î produces a variation of

C3S

Exc SO3 /tot.alk. (%)

W250 (kWh/t @ 250 m2/kg ) W300 W350 W400

-0.3 -0.5 -0.6 -0.7

4 4 5 5

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CaOl (%)

D75 alite (µm)

Alite C3S x100

-0.9

0.1 0.1 0.2 0.2

-0.1 -0.2 -0.3

BALL MILLING incl. SEPARATORS – Page 14/25 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-1 – BALL MILLING INCLUDING SEPARATORS

6.

Mill Performance Benchmarking

6.1.

Performance Indicator Finish Mills Absorbed (PIFMA)

The PIFMA is used to benchmark finish mill performance:

PIFMA =

Where: PA – actual specific power consumption mill drive PT – quasi theoretical specific power consumption, calculated from standard grindability figures

PA PT

An efficient mill will have a PIFMA close to unity The theoretical power consumption at a standard surface of 300 m2/kg calculated by:

(

1 P = • X C • SPC C + X G • SPC G + X S • SPC S + X A • SPC A + X P • SPC P + X L • SPC L + X O • SPC O T 300 MF

)

Where: XC, XG, XS, XA, XP, XL and XO are the weight fractions of clinker, gypsum, slag, flay ash, pozzolan, limestone and other components in the product. MF is the mill type factor = 1 for a ball mill, =1.6 for a Horomill, = 1.7 for Vertical mill and 1.8 for a roller press SPC refers to the standard grindability kWh/t of the components at 300 m2/kg. The standard figures used are: SPCC SPCG SPCS

Clinker Gypsum Slag

28 10 43

SPCA SPCP SPCL

Fly Ash Pozzolan Limestone

2 10 10

Note the low figure used for fly ash is to adjust for it’s initial surface The theorectical specific power consumption at 300 m2/kg is then corrected to the actual product surface area SA, by the following equation:

P = P T T 300

⎛ SA • (1 − 0.1 * ( X G + X A •⎜ 300 ⎝

+ X P + X L )) ⎞

fs

⎟ ⎠

Where: fs = Factor Separator (1.6 for open circuit, 1.5 for first, 1.4 for second, 1.3 for third generation separator, 1.0 for roller press, 1.10 for vertical mill & 1.05 for Horomill) Subtraction of the term 0.1*(XG+XA+XP+XL) from the surface area is meant to correct for over-grinding of the softer components. The resulting PIFMA will be influenced by the mill efficiency and by the grindability of the cement. Therefore especially in cases of high PIFMA (>1.15) the grindability of the components and the condition of the milling system will need to be investigated to find improvement potential. Example Calculation of PIMFA

Determine the PIFMA of a closed circuit ball mill with 3rd generation separator produces 86.2 tph @ 369 m2/kg with a power consumption at the main motor of 35.6 kWh/t. The product components are 88.29% clinker, 3.47% gypsum, 6.56% limestone and 1.68% blast furnace slag.

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BALL MILLING incl. SEPARATORS – Page 15/25 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-1 – BALL MILLING INCLUDING SEPARATORS

Calculate the theoretical power consumption at a standard surface of 300 m2/kg by:

(

1 P = • X C • SPC C + X G • SPC G + X S • SPC S + X A • SPC A + X P • SPC P + X L • SPC L + X O • SPC O T 300 MF

(

)

1 P = • 0.8829 • 28 + 0.0347 • 10 + 0.0168 • 43 + 0.0656 • 10 = 26.4 kWh / t T 300 1

Next calculate the theoretical power consumption at the actual product surface area using:

⎛ SA • (1 − 0.1 * ( X G + X A •⎜ 300 ⎝

P = P T T 300

P T

+ X P + X L )) ⎞

⎛ 369 • (1 − 0.1 * ( 0.0347 + 0.0656)) ⎞ = 26.4 • ⎜ ⎟ 300 ⎠ ⎝

fs

⎟ ⎠

1.3 = 34.2 kWh / t

Finally calculate the PIFMA PIFMA =

6.2.

P A = 35.6 = 1.04 34.2 P T

Benchmarking Ball Mills with Bond Wi

Bond is most useful for assessing the power consumption of ball raw mills and coal mills since both target product particle size rather than surface area: The power consumption for a new mill can be estimated from the Bond Equation:

⎛ 10 10 ⎞⎟ − Ws = FB • 1.102 • Wi • ⎜ ⎜ P 80 F80 ⎟⎠ ⎝

Where: Ws – calculated industrial mill shaft power kWh/t P80 – Product 80% passing size µm F80 – Feed 80% passing size µm FB - Bond Factor for dry grinding normally 1.3

The 1.102 is the conversion from kWh/short ton to kWh/t (metric) . For grinding finer than 70µm Bond proposed a fine grinding correction factor, calculated from:

⎛ 10.3 + P80 FP = ⎜⎜ ⎝ 1.145 • P80

⎞ ⎟⎟ ⎠

The Bond equation can also be used for benchmarking existing mills in conjunction with actual mill shaft power consumption (WSA kWh/t) to compute the Bond factor:

FB =

WSA ⎛ 10 10 ⎞⎟ − 1.102 • Wi • ⎜ •F ⎜ P 80 ⎟ P F 80 ⎠ ⎝

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BALL MILLING incl. SEPARATORS – Page 16/25 Version September 2010

)

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-1 – BALL MILLING INCLUDING SEPARATORS

Values of less than 1.3 would normally indicate an efficient mill. Typical values determined for specific mill types grinding cement raw materials are: 1. 2. 3. 4.

Bucket elevator ball mill Tandem Hammer / Airswept mill Airswept Mill Double Rotator Mill (Central discharge)

1.2 – 1.3 1.4 – 1.5 1.4 – 1.55 1.2 – 1.3

The Bond equation is also useful to assess the potential impact of changes to mill feed or product size.

7.

Separator

7.1.

Circulating Load (CL)

Junction with Three Streams • A, R, F are the feed, rejects and fines of the separator A ai , ri , f i are the cumulated % passing at a defined sieve(i).

F

R

-

da, dr, df are the % retained corresponding to the sieve interval dx.

-

A=R+F A da = Rdr + Fdf

With:

da = a i + 1 − ai ,

R df − da = , A df − dr

Drawing • Plot ( f i − a ) vs ( f i − ri ) If the mill circuit is steady, the graph has to be a straight line:

( f − a) = α + β( f − r )

-

α should be close to 0

-

β is the most probable value of

-

The circulating load is defined as:

7.2.

CL calculation • Using the least square line calculations, with α = 0 Quick CL calculation • With one set of results of sieving: R f −a = F a−r

β R = F 1− β

Tromp Curve

a) •

R A

F dr − da = A dr − df

Creating the Tromp Curve On the Gauss-logarithmic paper, let's plot the probability for a given particle of a certain size entering the separator to go to the rejects =

dr( x )* R with: da( x )* A

n

∑

( f i − ai )( f i − ri ) R i =0 = n A ( f i − ri ) 2

∑

i =0

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BALL MILLING incl. SEPARATORS – Page 17/25 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-1 – BALL MILLING INCLUDING SEPARATORS

The Tromp curve can be divided into two straight lines The higher sieve fractions have a slope which is representative of the separator efficiency (a perfect one would be vertical).

•

Tromp Curve Representation

OSEPA N1500

99.8 99.5 99 98 95 % Probability of Rejection

•

90 80 70 60 50 40 30 20 10 5

1.0

10.0

100.0

1000.0

Particle Size

b) •

Imperfection d 75 − d 25 I= 2 * d 50

where: - d25 is the size of the particle which has 25 % chance of going to rejects - d50 is the size of the particle which has 50 % chance of going to rejects - d75 is the size of the particle which has 75 % chance of going to rejects

Imperfection vs Circulation Load 0.44 Imperfection 0.42 0.40 0.38 0.36 0

c) • •

d)

100

200 300 Circ. load (%)

400

Acuity Limit AL is the abscissa of the intersection of the two Tromp curve lines. It’s the size at which selection is initiated

Bypass

Definition: • By-pass is the ordinate of the intersection of the two Tromp curve lines. • The bypass is the lowest percentage of feed that will go to the separator rejects.

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BALL MILLING incl. SEPARATORS – Page 18/25 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-1 – BALL MILLING INCLUDING SEPARATORS

Bypass vs. feed rate – Sturtevant • The following graph shows the Bypass of an 18’Sturtevant versus its feed rate.

Bypass vs. feed rate O’Sepa/Sturtevant 80

100

70 Bypass (%)

Bypass (%)

Sturtevant

60

80 60 40

50 40 30 20

O-Sepa

10

20

0 1.0

100 150 200 250 Feedrate to Separator (t/h)

QF/Qa vs. bypass • If Qf is the separator feed rate (kg/h) and Qa the separator ventilation (m3/h), • Qf/Qa is an important ratio for the separator efficiency.

•

⎛ Qf ⎞ ⎜⎜ − f1 ⎟ Qa ⎟⎠ ⎝

•

•

2.0

2.5

3.0

3.5

40 30 20 10

Bypass = 1 + e - f1: coefficient for the separator

7.3.

1.5

Qf/Qa (kg feed/m3 separator sweep)

300

Rosin Rammler Number (RR#)

The steeper the particle size distribution (RR# high) the more efficient the grinding and separating process. Raw mix RR# are usually lower than those for cement grinding

0 0

1

2 Qf/Qa (kg/m3)

3

4

RRnumber vs. Feed to Air Ratio 1.20 Rosin-Ramler Number (n)

50

Bypass (%)

0

1.15 1.10 1.05 1.00 1.0

1.5

2.0

2.5

3.0

3.5

4.0

Qf/Qa (kg/m3)

Separator Performance • Rate of recuperation in the fines of particles smaller than a given dimension.

r=

7.4.

F f * A a

Indicators for Cement Milling and Typical Values

Slope Rosin Rammler fines: % recovery, 45 μm: Acuity: Imperfection:

Bypass: Circulating load: HES Qf/Qa: % Passing 45 μm:

1.1 – 1.4 for HES 0.85 – 1.0 for 1st generation separators (Sturtevant, Raymond) 1.2 for second generation separators 45 to 55% for Sturtevant and >65% for HES 20 – 30μm for Sturtevant and <0.30μm for HES <0.35 for HES 0.45 – 0.6 for Raymond separators 0.6 –0.7 for Sturtevant separators 5 – 10% range for HES 150 –200 % with HES 1.5 – 2.0 range 93% minimum (45 μm = 325 mesh)

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BALL MILLING incl. SEPARATORS – Page 19/25 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-1 – BALL MILLING INCLUDING SEPARATORS

7.5.

Recommended Sizing for a HES Parameter

Recommended

Possible (Min/Max)

Industrial Range

Cage loading

20-23 t/h/m2

less than 30

11-36 t/h/m2

Qf/Qa

2 kg/m3

less than 2,2

0,7-3,0 kg/m3

Radial velocity at the inlet of the cage

3,6-4,3 m/s

x

2,9-4,5 m/s

Ratio Am3/h/m2 Gas volume / Cage Area

14 000 Am3/h/m2

13000-15000 Am3/h/m2

10500-16300 Am3/h/m2

Circulating load

100%-250%

x

45%-270%

1,0 m/min Pulse jet H.P.

less than 1,2 m/min

Filtration Velocity or Air to cloth ratio

a) • • • • •

•

0,8-1,3 m/min 1,1 m/min Pulse jet L.P.

less than 1,2 m/min

Fan and Bag House Sizing Use the production rate (T/h), Qf/Qa (kg/ Am3) and circulating load (%) to specify the air flow. Most separators can operate at +/- 20% of nominal. Only a margin of 5 - 8% above the separator airflow is recommended for the BH. Margin of 5-10% is recommended on top of the BH for the fan. Correctly specifying the static pressure: - Pressure drop can be estimated by the dP of the separator (2.5 – 3 kPa), Dust Collector (2 – 2.5 kPa), ducting. (1-1.5 kPa) and if present, silencer (250 – 500 Pa). - The recommendation is 6.5 kPa with a minimum of 600 kPa. Include in the circuit design, the possibility for recirculation of up to 80% of the separator airflow.

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BALL MILLING incl. SEPARATORS – Page 20/25 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-1 – BALL MILLING INCLUDING SEPARATORS

8.

Grinding Aid

Type of Products • Surface active agents tend to saturate the free valence and inhibit the pack-set. Typical surfaceactive agents are: - ligno-sulphonates - polyoils - amines - organic acids • Polar compounds (water, ammonia) are known to have some action on such bonds through their polar moment. However, their practical use as surface agents is limited by their other impacts on the cement properties. • Other agents, particularly coal dust, have been used in the past. • Commercial products available as grinding aids are essentially (60-800 g/t ck): - Triethanolamine - Polypropylene glycols and polyethylene • HEA2, DDA& and other products cause a definite reduction of pack-set but do not prevent agglomeration or lump-formation problems that are caused by: - Alkalis ( K 2 SO4 ) - Moisture The effect of grinding aid on milling process: - Enhances the flowability and prevents agglomeration - Prevents coating on liners and grinding media - Lower effect on coarser product (below 320 m2/kg) - Reduces contraction - Increased production (5-7%)

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BALL MILLING incl. SEPARATORS – Page 21/25 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-1 – BALL MILLING INCLUDING SEPARATORS

9. 9.1.

Other Data Sieve Sizes

Sieve Screen #400 #325 #270 #230 #200 #170 #140 #120 #100 #80 #70 #60 #50 #45 #40 #35 #30 #25 #20 #18 #16

9.2.

Micron 37 44 53 63 74 88 105 125 149 177 210 250 297 354 420 500 595 707 1000

Iso alter 38 45 53 63 75 90 106 125 150 180 212 250 300 355 425 500 600 710 850 1000 1180

Screen #14 #12 #10 #8 #7 #6 #5 #4 #3.5 1/4" 5/16" 3/8" 7/16" 1/2" 5/8" 3/4" 7/8" 1" 1"1/4 1"1/2 2"

Micron 2000

6350 8000 9510 11200 12700 16000 19000 22600 25400 32000 38100 50800

Iso alter 1400 1700 2000 2360 2800 3350 4000 4750 5600 6300 8000 9500 11200 12500 16000 19000 22400 25000 31500 38100 50000

Bulk Densities Bulk density Sand Sand Iron Bauxite Brick Gypsum Fluid coke Limestone (crushed) Silica fume Bottom Ash Cement T I-II T 10 T III Clinker Clinker (underburnt) Raw mix

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kg/m3 1387 1679 2629 1980 1502 1677 926 1803 1024 1241 1234 1207 1054 1575 1400 1041

BALL MILLING incl. SEPARATORS – Page 22/25 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-1 – BALL MILLING INCLUDING SEPARATORS

9.3.

Residue Conversion Chart CONVERSION OF SIEVE RESIDUES

% residue at 90μm 70

50 40

30

355 μm 20

250 μm 12.0% 10 200 μm 7

5

180 μm

150 μm

4

3 125 μm 2

106 μm 1

0.7

0.5

90 μm

0.4 80 μm 14.22%

63 μm 0.2

75 μm

56 μm

% residue

0.3

12.0%

50 μm 25 μm

45 μm 0.1

0.7

1

2

3

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4

5

7

10

20

30

40

50

BALL MILLING incl. SEPARATORS – Page 23/25 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-1 – BALL MILLING INCLUDING SEPARATORS

10. References ¾

Cement Portal Grinding Domain ™ How to manage the ball charge level ™ How to check the airflow through the mill ™ How to do a routine stop inspection ™ How to do a mill crash stop inspection ™ How to optimise a ball charge ™ How to manage liner wear in a ball mill ™ How to conduct a ball mill audit ™ How to remove scrap from a ball mill circuit ™ How to check the separator efficiency ™ Procedure for audit of Ball Mill Circuits ™ Global mixing grinding media recommendations ™ Technical agenda study – formalisation of knowledge on grinding aids ™ Guide – ball mill optimisation Post Sevilla module 5 ™ Priority study cement grinding workshop ™ Priority study – separators

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CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-1 – BALL MILLING INCLUDING SEPARATORS

My notes:

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CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-2 – VERTICAL RAW MILL

1-2. Vertical Raw Mill

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VERTICAL RAW MILL – Page 1/11 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-2 – VERTICAL RAW MILL

Table of Contents 1.

Raw Mill Parameters ...................................................................................3 1.1

Feed Size........................................................................................................ 3

1.2

Table Speed ................................................................................................... 3

1.3

Grinding Pressure........................................................................................... 3

1.4

Bed Depth....................................................................................................... 5

1.5

Dam Ring Height ............................................................................................ 5

1.6

Nozzle Ring & External Recirculation............................................................. 5

1.7

Gas Flow......................................................................................................... 6

1.8

Mill Temperatures ........................................................................................... 6

1.9

Mill Pressure Drop .......................................................................................... 6

1.10 Gas Speeds .................................................................................................... 6 1.11 Material Load at Separator Outlet .................................................................. 6

2.

Table & Roller Liners Wear.........................................................................7

3.

Performance of Lafarge Vertical Raw Mills...............................................7

4.

Vertical Mill Parameter Optimisation.........................................................9

5.

References .................................................................................................10

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VERTICAL RAW MILL – Page 2/11 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-2 – VERTICAL RAW MILL

1.

Raw Mill Parameters

1.1

Feed Size

The largest particle size should be maximum 3 - 4% of the roller diameter Typical feedsize distribution:

100% passing 100mm 95% passing 60mm Maximum 10% passing 1mm Reducing feedsize can increase production, but avoid excessive fines which can increase vibration

1.2

Table Speed

The table speed of a vertical mill is defined as: Nc =

C Dt

Dt table diameter m

Where:

C is constant (ranging from 40 – 55) specific to each mill design (check if we have values from other suppliers) Typical speeds for different suppliers: % critical Polysius

81

FLS & Loesche

84

Pfeiffer

70

Raw mills have fixed speed drives, a faster turning table will tend to be more sensitive to fine feed material than a slower one.

1.3

Grinding Pressure

Typical operating values for nominal production are: 1.

Polysius :

130 – 150 bars

2.

Loesche :

80 – 90 bars

3.

Pfeiffer

120 -150 bars

4.

FLS Atox :

110 – 120 bars

5.

FLS FRM :

75 – 80 bars

:

Grinding pressure is not directly comparable between different suppliers due to hydraulic system (e.g cylinder size number cylinders, etc) and grinding roller arrangement

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VERTICAL RAW MILL – Page 3/11 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-2 – VERTICAL RAW MILL

Calculation of grinding forces (for track guided rollers): d Grinding Force Applied

α

Static load Ls= W x g kN Dynamic load Ld= 100 x P x N x π x (D2-d2) x Cos α 4 Total load applied Lt = Ls + Ld

kN

Where W P N D d α

P D

total roller weight including carriers t grinding pressure bars number hydraulic cylinders cylinder diameter m piston rod diameter m cylinder inclination from vertical degrees

Specific load applied surface area

Lsl =

Lt Ar

KN/m2

where Ar is projected roller

Typical installed specific loads for suppliers are : Pfeiffer

450

kN/m2

Loesche

880

kN/m2

FLS - FRM

880

kN/m2

FLS - ATOX

800

kN/m2

Polysius – RMK

1100

kN/m2

Calculation of grinding force for LOESCHE type mills: Static load: Ls = ( W1 + 0.6* W2 ) *g With W1 : weight of the roller W2 : weight of the roller shaft NB: coefficients for W1 and W2 are estimated from available drawings Weight of the roller arm is neglected Dynamic load: Ld = F * K * N with: F: force applied by one cylinder K: lever ratio (ratio supplied by LOESCHE: 0.838 for FR_SPL_LM 46 2+2) N: number of cylinder per arm F = π /4 ∗ ( ( D2 – d2 ) * P – D2 * p ) *100000 with: D: cylinder diameter (m) d: cylinder rod diameter (m) P: grinding pressure (bar) p: counter pressure (bar)

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VERTICAL RAW MILL – Page 4/11 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-2 – VERTICAL RAW MILL

Specific load calculation: Specific load = Lt / (( D + d )/2 * L ) D l

d

L

1.4

Bed Depth

Bed depth is normally in the range of 50 – 80 mm Optimum bed depth can be defined as the lowest possible bed depth that keeps the mill vibrations in a safe range.

1.5

Dam Ring Height

Usual range for dam ring height: 2.5 – 4.0 % of table diameter, but varies according to table design, wear, feed materials, etc….

Dam Ring Height Table Segment Grinding Table

1.6

Nozzle Ring & External Recirculation

•

Gas speeds for nozzle rings vary depending upon the capacity of the external recirculation system:

•

25 – 60 m/s for recirculation of 50 –100 % fresh feed

•

70 + m/s with no recirculation

•

Nozzle ring -

ƒ ƒ •

inclined at 60° to direct larger material back to the table Blades inclined at 60° to give some pre-separation

External Re-Circulation -

ƒ ƒ

Some mills (Polysius) are designed 100% recirculation relative to mill feed. A maximum operation level of 50% external recirculation is recommended to keep mill stability. Note: Nozzle ring velocities based upon free area of the nozzle ring perpendicular to the nozzle ring guide vanes.

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VERTICAL RAW MILL – Page 5/11 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-2 – VERTICAL RAW MILL

Direction of table rotation nozzle

Dam Ring

Grinding Table Air guide cone

1.7

Gas Flow Direction

Gas Flow

Typical gas flow measured at mill outlet : 2 – 2.5 m3/kg (or 400 to 500 g/m3). Benchmark false air level < 15% mill fan volume

1.8

Mill Temperatures

Mill outlet temperature:

•

Typical 80 - 110 °C depending upon feed moisture

•

Mill outlet temperaure +20 - 30°C above dewpoint

Mill Inlet Temperature:

•

The maximum allowable temperature at the mill inlet = 325 - 350 ºC without insulated grinding table

•

Higher temperatures can be achieved with an insulated grinding table, although some older mills are limited due to roller lubrication Note: Raw materials with very high moisture requiring a high mill inlet temperature and in such cases these mills are supplied with an insulated grinding table and modified nozzle ring. When made in special materials, a mill inlet temperature of up to 550 ºC can reached.

1.9

Mill Pressure Drop

Mills with external recirculation 50 – 60 mbar Mills without external recirculation 70 – 85 mbar.

1.10

Gas Speeds

Mill casing

: 4.5 – 7.0 m/s (For Vertical Transport)

Separator

: 4.5 – 6.0 m/s (Through the cage rotor – based on gross area)

Ducts

: 18 – 20 m/s

1.11

Material Load at Separator Outlet

Separator outlet material load 500 - 600 g/m3 Separator drive speed – tip velocity 20 – 26 m/s Vertical centre feed arrangement with raw material feed moisture > 15%

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VERTICAL RAW MILL – Page 6/11 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-2 – VERTICAL RAW MILL

2.

Table & Roller Liners Wear

Optimum liner selection (typical lifetimes + influences on wear)

•

Wear resistant Chromium Steel – standard solution for low abrasive mixes

•

Ni- Hard Tyres with Re-welding insitu – solution for abrasive mix

•

Liners with ceramic inserts – most wear resistant option for abrasive raw mix

•

Normal liner wear 2g/t raw mix, high wear up to 7 g/t

•

Liner lifetime is most important to allow replacements during major kiln repairs

•

Worn liners can reduce production by 10%

Vertical Mill Table Liner Optimisation Example – Switch from welding to Ceramic Liners Write the text of the example here (the borders will be removed on the final version) SCK Raw Mill Table Liner Wear History

Outer Path Average Wear (mm) Inner Path Average Wear (mm) Outer Path-Highest Wear Point Inner Path-Highest Wear Point

Projected

70.0

8/24/2004 Weld Rebuild

8/15/2005 Recentered Roll Axis, Weld Rebuild Outer Track

60.0 1/10/2004 Replace Standard Cast 4/19/2004 Weld Rebuild

Wear (mm)

50.0

1/10/2005 Replace X-win Ceram ic Inner Track

40.0

9/13/2005 100% UGM Rock

7/6/2007 7/23/2006

30.0 20.0 8/15/2006

10.0

3.

8/6/2007

9/25/2007

6/17/2007

3/9/2007

4/28/2007

1/18/2007

11/29/2006

10/10/2006

7/2/2006

8/21/2006

2/2/2006

5/13/2006

3/24/2006

12/14/2005

9/5/2005

10/25/2005

7/17/2005

4/8/2005

5/28/2005

2/17/2005

11/9/2004

12/29/2004

8/1/2004

9/20/2004

6/12/2004

3/4/2004

4/23/2004

1/14/2004

10/6/2003

11/25/2003

8/17/2003

Date

6/28/2003

0.0

Performance of Lafarge Vertical Raw Mills

Reliability factor target:

> 95 %

Actual (2009): 24 mills from 53

Annual Incident Stops target:

< 100

Actual (2005): 3 mills from 24

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VERTICAL RAW MILL – Page 7/11 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-2 – VERTICAL RAW MILL

Lafarge Data (2005)

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VERTICAL RAW MILL – Page 8/11 Version September 2010

Requirements

Maintain just above minimum (start up with high airflow)

Minimise false air (benchmark 15% mill fan volume). Regular checks combined with regular leak identification and repair A low as possible, but keep rejects <50% fresh feed. Nozzle Ring Velocity Adjust airflow distribution around mill to increase at roller discharge Minimised by nozzle ring and dam ring adjustment Pressure drop

© Copyright 2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

Plough (if fitted)

Water addition Table

Product Residue

Increased vibration, difficulty in keeping stable bed on table maintain clearance from table to avoid excessive rejects Excessive material hold up and high mill power

Excessive power consumption, liner wear and high preheater dust loss

control separator speed/ guide vanes to achieve target

sufficient to stabilise bed

Suspect calibration of power meters or mill feedrate

Inadequate process control loop / underdesign of fan Mill may not be optimised

Mill empty - not optimised

Excessive rejects/ elevator power

minimise according to operating strategy

Equivalent to 50% fresh feed

Elevator Power

Power Consumption

Sufficient to maintain airflow

Fan Speed

False Air

Increase liner wear and increased mill power consumption Excessive rejects

Poor control, separator problem and difficult burnability in kiln

mill filling and risk of overload trip Inadequate process control loop High external load can destabilise mill and make restarts difficult due to large pile on table Mill not optimised for power consumption

Reduced production, high power consumption and possible operational issues High mill pressure loss and high power consumption

thin grinding bed, low circulating load and low pressure loss Mill not optimised

deep grinding bed, high circulating load and high pressure loss mill will fill up, potential overload trip N/A

Airflow

Hyd Press

risk of mill trip

Risk damage to mill parts low grinding efficiency Excessive bed depth and high mill power

Mill filling and overload

Too high

Mill may not be optimised

Max feed will be close to maximum (tends to increase as table wears) Matched to bed depth

Mill Drive Power

High Power Consumption

Too low

Maintain at a safe level Maintain at level to keep vibration at safe level High vibration To be adjusted as table wears to keep bed depth under Low bed depth, high vibration normal condition and high elevator power

Strategy 2 - Keep pace with kiln minimise kiln upsets

Strategy 1 - Maximise to reduce Power Consumption

Pfeiffer - 250 mm feedsize 70mm Polysius 70mm - Feedsize 40mm

1 - 3% of mill feed

10 -12 % residue 90µm <1 % residue 212 µm

Mill only 5- 8 kWh/t Total 13 -17 kWh/t

50% fresh feed Elevator power is normally calibrated as tph

3.5 - 5 kPa w recirc 6 - 10 kPa w/out recirc 90 -95 % on a well sized system

25 - 60 m/s w recirc 60 - 90 m/s w/out recirc

80 - 90% of maximum 1.8 - 2.2 nm3/kg with low moisture 15 - 25% mill fan volume

80 - 90 % installed

2-3 mm/s 50 - 80 mm 50 - 150 mm Pol/Loesche/FLS Pfeiffer 0 - 50mm

Typical level

4.

Vibration Bed depth Dam ring

Feedrate

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-2 – VERTICAL RAW MILL

Vertical Mill Parameter Optimisation

VERTICAL RAW MILL – Page 9/11 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-2 – VERTICAL RAW MILL

5.

References

•

Technical Agenda Study – Vertical Raw Mill

•

Procedure "How to do on-line diagnostic of a vertical mill"

•

Procedure "How to do on-stop inspection of a vertical mill"

•

Procedure "How to adjust the dam ring of a vertical mill"

•

Cement Portal's Grinding Domain

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VERTICAL RAW MILL – Page 10/11 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 1-2 – VERTICAL RAW MILL

My notes:

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VERTICAL RAW MILL – Page 11/11 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-1 – COMBUSTION & FUELS

2-1. Combustion & Fuels

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COMBUSTION & FUELS – Page 1/26 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-1 – COMBUSTION & FUELS

Table of Contents 1.

Fuel Theory – Heat Value ................................................................ 3

2.

Solid Fuel .......................................................................................... 7 2.1. 2.2.

3.

Coal ................................................................................................................. 7 Coke ................................................................................................................ 9

Fuel Oil............................................................................................ 10 3.1. 3.2.

Main Characteristics...................................................................................... 10 Viscosity ........................................................................................................ 10

4.

Natural Gas ..................................................................................... 11

5.

Typical Preheater Exit Gas............................................................ 13

6.

Flame Theory.................................................................................. 14 6.1. 6.2. 6.3. 6.4.

7.

Definition ....................................................................................................... 14 Flame Speed ................................................................................................. 14 Flame Radiation ............................................................................................ 14 Factors Influencing the Flame Temperature ................................................. 14

Burner Pipes................................................................................... 15 7.1. 7.2. 7.3. 7.4.

Number of Air Circuits ................................................................................... 15 Primary Air..................................................................................................... 16 Lafarge Burner Operation and Design Basics .............................................. 16 Burner Alignment........................................................................................... 20

8.

Combustion Success Criteria ....................................................... 20

9.

Fuel Grinding and Dosing ............................................................. 22 9.1. 9.2. 9.3. 9.4. 9.5.

Solid Fuel Grindability ................................................................................... 22 Solid Fuel Fineness....................................................................................... 22 Dosing ........................................................................................................... 23 Safety Considerations ................................................................................... 24 Fuel Grinding Mills......................................................................................... 24

10. References...................................................................................... 25

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COMBUSTION & FUELS – Page 2/26 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-1 – COMBUSTION & FUELS

1.

Fuel Theory – Heat Value

Quick Energy Conversion Factors MJ/kg

= kcal/kg / 238.846

MJ/kg

= Btu/lb / 429.923

kcal/kg

= MJ/kg * 238.846

kcal/kg

= Btu/lb / 1.8

Btu/lb

= MJ/kg * 429.923

Btu/lb

= kcal/kg * 1.8

List of Abbreviations HHV LHV C H N O S A M VM FC Cl

high heat value or gross calorific value low heat value or net calorific value % weight carbon % weight hydrogen % weight nitrogen % weight oxygen % weight sulfur % weight ash % weight total moisture % weight volatile matter % weight fixed carbon % weight chlorine

W

moisture/hydrogen water factor

Subscripts d dry basis ad air dried (includes inherent moisture) ar as received (includes total moisture) af as fired daf dry basis, ash free

•

High Heat Value (HHV) The High Heat Value is the result obtained out of the Oxygen bomb calorimeter. It is the heat produced by complete combustion at constant volume, with the resulting water condensed to liquid. Per definition Sulphur remains SO2 and N is not oxidized, energy of acid formation is therefore subtracted using the S and N content of the fuel. The moisture of the fuel has a strong impact on the heat value, the moisture of the sample used in the calorimeter (typically air dry) is different to the moisture at the plant firing point. To have a clear reference HHV and LHV reported from the laboratory should be dry (except for liquid fuels, they are reported and analyzed on wet base). HHV dry = HHV * 100 / (100 – M) M = Moisture of the sample analyzed in the bomb calorimeter.

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COMBUSTION & FUELS – Page 3/26 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-1 – COMBUSTION & FUELS

•

Low Heat Value (LHV) Dry basis – Lafarge Definition following ISO In practice the water out of combustion remains gaseous and the combustion takes place at constant pressure. LHVdry (Low Heat Value dry) is calculated from the High Heat Value dry subtracting the condensation energy and considering the volume change coming from Nitrogen, Oxygen and Hydrogen in the fuel.

LHVdry = {HHVdry − 212 ⋅ ( Hdry ) − 0.8 ⋅ [(Odry ) + ( Ndry )]} (ISO) LHVdry = Low Heat Value dry in kJ/kg HHVdry = High Heat Value dry in kJ/kg To have a clear defined reference, LHV reported from the laboratory should be on dry base (except for liquid fuels). Oxygen and Nitrogen correction as shown above have small impact in typical coals and can be neglected if no elemental analysis is available. Should be careful with AF.

•

Low Heat Value as fired (correction for moisture)– Lafarge Definition The finally used heat value for heat consumption reporting is considering the moisture of the fuel at the firing point (example coal moisture after mill or SSW moisture,…).

LHVasfired = LHV dry ⋅ (1 − 0.01 ⋅ Masfired ) − 24.88 ⋅ Masfired M as fired = Moisture as fired [%], to be measured at the plant immediately after sampling. Remark: LHV wet corresponds to LHV as fired if moisture is identical (example liquid fuels). Remark: Alternative fuels with high moisture can have negative LHV. Low heat Value as fired is the one to be used for heat consumption reporting. LHV definitions from various standards – for reference LHV results out of standards differing to the Lafarge definition above or received from older calculation tools are acceptable as long as the difference is < 0.5% compared to the Lafarge definition result. Examples: ISO 1928-1995 (constant pressure and 25°C) LHVar (J/g)

= [HHVd – 212.2Hd – 0.8( Od + Nd )] x (1 – 0.01M) – 24.43M

World Coal Institute (WCI) LHVar (MJ/kg)

= HHVar – 0.212 Har – 0.0008Oar – 0.0245M

LHVar (Btu/lb)

= HHVar – 50.6Har – 0.191Oar – 5.85M

ASTM 5865/3180 (constant pressure) LHVar (J/g)

= HHVar – 215.5War

LHVar (Btu/lb)

= HHVar – 92.67War

Where: War = [(Had – 0.1119 Mad) x (100 – Mar)/(100 – Mad)] + 0.1119Mar Or in cases where you have just dry and as fired results: Waf = [Hd x (100 – Maf)/100] + 0.1119Maf (substitute War with Waf)

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COMBUSTION & FUELS – Page 4/26 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-1 – COMBUSTION & FUELS

•

Example of HHV - LHV and LHV as fired gap The difference between the HHV and the LHV will vary with fuel type. The greater the proportion of hydrogen in a fuel, the lower the resulting LHVdry. The higher the as fired moisture the lower the LHV as fired compared to LHV dry. Fuel

%H

Coal* Coke* Waste Fuel

5 4 10

Fuel oil Natural gas

10 25

HHVdry (MJ/kg) 27.91 32.56 20.93 HHV wet 44.19 53.50

LHVdry (MJ/kg) 26.83 31.70 18.78 LHV wet 42.04 48.11

% Moisture as fired 1% 0.5 % 10 %

LHV as fired (MJ/kg) 26.31 31.41 14.41

LHV as fired as % of HHV 94% 96% 69%

-

42.04 48.11

95% 90%

* Remark: if significant dust in gas used for coal/coke drying, e.g. preheater gase with no / inefficient cyclones, be careful to make adjustment when converting coal analysis to as fired basis. Can use difference in measured ash (corrected for CO2for greater accuracy) to assess dust capture.

Heat Value Estimation Combustion Equations

•

C + O2 → CO2 + 32778 kJ / kg C

•

1 H 2 + O2 → H 2 O + 11990 kJ / kg H 2

S + O2 → SO2 + 9265 kJ / kg S

•

Estimating Heat Value Calculation

•

If HHV was not determined and proximate + ultimate analysis is available it is possible to estimate calorific values for certain fuels.

•

For COAL:

⎡

LHVar (kJ/kg) = ( 80.8C ar + 22.45S ar + 287 * ⎢ H ar −

⎣

Oar ⎤ − 6M ) x 4.1868 8 ⎥⎦

HHVd (kJ/kg) = ( 80.8C d +22.45S d + 339.4 H d − 35.9Od ) x 4.1868 For TDF HHVd (kJ/kg) = 40,924.8 x (100 – Ad)/100 x 0.97

•

Valid for North American TDF (North American and European tires differs in composition)

For plastics and paper: = HHVar (MJ/kg) = 1.934766H+1.229411C+0.931257N+0.85302O+11.756341Cl +0.506425S-0.345919FC+0.557784M +0.581401A-86.338211478

• •

All parameters are as received basis Model based on regression of plastics paper and plastic resins analysis

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COMBUSTION & FUELS – Page 5/26 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-1 – COMBUSTION & FUELS

• • •

Valid if ash < 4% Model excludes PVC Model excludes specialty plastics (e.g. Dupont butacite)

For Biomass = HHV (in kJ/g) = 0.3491C +1.1783H - 0.1034O - 0.0211A + 0.1005S -0.0151N Reference: S.A. Channiwala 1992 Indian Institute of technology

Volatile Matter ƒ Volatile matter is the loss in weight, corrected for moisture, of a sample heated to 900oC (ISO) in the absence of air. • The volatile matter gives an indication of the reactivity of the coal – a higher volatile matter ignites at a lower temperature

Ignition Temperature vs. %VM 800

750

• The graph shows ignition temperatures for coal dust in air

Temperature, deg C

700

650

Probable Ignition Temperature

600

550

500

450

400 5

10

source: Polysius

15

20

25

30

35

40

45

Coal %VM

Ash ƒ

Ash is the inorganic residue remaining after burning solid fuel heated to 815oC (ISO) in an oxidizing atmosphere until there is no weight change. It is composed chiefly (95-99%) out of oxides of Si, Al, Fe, and Ca; Mg, Ti, S, Na, K, and trace elements can also be present.

ƒ

CAUTION: Coal ashes contain sulfur, the total S of the fuel is analyzed and reported separately. The laboratory therefore has to subtract the Sulphur and report ash content as well as ash analysis Sulphur free. For ultimate fuel analysis the Carbon dioxide in ash needs to be subtracted as well.

Fixed Carbon ƒ The proximate analysis, giving the fixed Carbon, gives some indication of the fuel. FC = 100 – (A + M + VM) FC…% Fixed Carbon A…% Ash Content M…% Moisture VM…% Volatile Matter

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COMBUSTION & FUELS – Page 6/26 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-1 – COMBUSTION & FUELS

Ultimate Analysis

The ultimate analysis is the complete elemental analysis of the fuel. It is required for heat balances and process calculations like exit gas calculation or volatile balances. The ultimate analysis gives in addition to the heat value the complete elemental analyze of the fuel: C, H, N, S, Cl as well as ash. Ash composition should be analyzed if ash content is > 5% (ash then calculated S and CO2 free). Oxygen is often calculated out of total – in ideal case separate Oxygen analysis is available but needs to be corrected for Oxides in ash. The ultimate analysis should be reported from the laboratory on dry base for solid fuels and is then converted to as fired for process calculations.

%Casfired = %Cdry ⋅ (1 − 0.01 ⋅ % Masfired ) C as fired = % Carbon as fired C dry = % Carbon dry M as fired = % Moisture as fired Calculation is identical for all elements. Liquid fuels are directly reported wet, corresponding to as fired.

2. 2.1.

Solid Fuel Coal

Lafarge Business Reference System (BRS) definitions: High quality coals, according to the BRS are: 1. >22.5 GJ/t or 9673 Btu/lb 2. 12% < VM < 36% 3. Pyritic sulfur < 1% Low quality coals, according to BRS are: 1. <22.5 GJ/t or 9673 Btu/lb 2. VM <12% or VM >36% 3. Pyritic S >1% High quality cokes, according to the BRS are: 1. Total S < 5.5% 2. HGI > 45 Low quality cokes, according to the BRS are: 1. Total S > 5.5% 2. HGI < 45 For coke, if only one parameter is met, Sulfur takes precedence. Pyritic S in coal is not systematically measured. In such cases the pyritic S criteria can be ignored.

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COMBUSTION & FUELS – Page 7/26 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-1 – COMBUSTION & FUELS

Classification of Coals by Rank

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COMBUSTION & FUELS – Page 8/26 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-1 – COMBUSTION & FUELS

Typical analysis (reminder: “every coal is different”)

Anthracite

Coal

Lignite

0.3

1.1

6.3

Volatiles [%]

4

21.9

45.2

LHV [kJ/kg]

30000

23555

21000

Ash [% dry]

10

22.2

16.4

Carbon [% dry]

79.5

65.3

59.2

Hydrogen [% dry]

1.8

2.9

5.8

Oxygen [% dry]

6.6

7.2

15.1

Nitrogen [% dry]

1.6

1.7

0.5

Chloride [% dry]

0.01

0.008

0.003

Sulphur [% dry]

0.5

0.6

2

Moisture after mill[%]

2.2. •

Coke Coke is the solid, cellular, infusible material remaining after carbonization of coal, pitch, petroleum residue and other carbonaceous materials. Thus, its oxydation takes more time: 1 to 2 seconds.

Delayed Coke LHV

MJ/t

Fluid Coke

34 300

31 000

%C

88 – 90

87 – 88

%H

3.9 – 4.5

2–3

21

35

C/H Ratio %S

2–6

5–8

ASH content (%)

0.5 – 1.5

2–8

Volatile matter (%)

10 – 15

5 – 10

Granulometry (mm)

0 – 50

0–8

Moisture content (%)

7 – 10

5 – 10

Ignition Temperature

220 - 250

230 – 250

Hard Grove (HGI)

90 – 100

10 - 30

Refer to ‘How to Burn Petcoke’ in Cement Portal

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COMBUSTION & FUELS – Page 9/26 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-1 – COMBUSTION & FUELS

3.

Fuel Oil

3.1.

Main Characteristics Comp

Nº1

Nº2

Nº4

Nº6 FO

Nº6

C

86.4

87.3

86.47

87.26

84.67

H

13.6

12.6

11.65

10.49

11.02

O

0.01

0.04

0.27

0.64

0.38

N

0.003

0.006

0.24

0.28

0.18

S

0.09

0.22

1.35

0.84

3.97

Ash

<0.01

<0.01

0.02

0.04

0.02

C/H ratio

6.35

6.93

7.42

8.31

7.62

0.849

0.902

0.965

38 or legal

55 or legal

60

Specific Gravity Flashpoint (min. specification) °C

•

Api Gravity = ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ

3.2.

38 or legal

141.5 − 131.5 ( for SG < 1) Specific Gravity

No. 1, 2, 3 are called distillate fuel oils, distillate, light or diesel oils No. 1 is similar to kerosene No. 2 is diesel fuel or heating fuel No. 3 is rarely used No. 4 is a blend of distillate and residual oils – No. 2 and No. 6. Confusing as No.4 can be classed as diesel, distillate or residual fuel oil No. 5, 6 are residual fuel oils or heavy fuel oils – the remains after lighter fractions have been extracted. Mostly No. 6 is produced No. 5 is a mix of 75%-80% No.6 + balance No. 2. No. 6 may contain some No.2 to meet specifications

Viscosity

Theory

•

The viscosity of a fluid is a measure of its internal resistance to flow. Viscosity is the opposite of fluidity.

ƒ

absolute viscosity is absolute viscosity, μ measured in cp (centipoise);

ƒ

kinematic viscosity is kinematic viscosity, C measured in cs or cSt (centistokes)

ƒ

absolute viscosity in cp = kinematic viscosity in cs * specific gravity

1 poise = 100 cp = 1 dyne.s/cm2+ = 1 g/s*cm, 1 stoke = 100 cs = 0.000 1 m2/s Viscosity - temperature information for selected fuel oils

•

The far right-hand columns list temperatures required to reduce the oil viscosity to levels often required for easy pumping (440cSt) and for atomization (20.7cSt).

•

Required:

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COMBUSTION & FUELS – Page 10/26 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-1 – COMBUSTION & FUELS

ƒ

Viscosity: 20-25cSt, filtration<125μm (abrasion and clogging: 3-stage filtration at 35, 60 and 120#)

ƒ

Variation at the pump should not be higher than 5cSt

ƒ

(from North American Combustion Handbook, 2nd ed. 1978, table 2.9) Type of oil

Viscosity (ν) at 38C (cs)

#6 max #6 typical #6 min #5 max #5 typical #5 min #4 max #4 typical #4 min #2 max

2200 259 220 165 67.2 32.1 20.7 11.7 6.9 3.5

Oil temperature (in C) required for pumping Atomization 59 129 30 93 28 91 22 83 8 66 -7 50 -17 38 -28 25 -59 -3 --17

WARNING: for No. 5 and No. 6 fuel oils, atomization temperatures are above the minimum flash point.

Other Viscosities (for comparison only)

•

4. a)

At ºC

Water

Air

Natural gas

μ (cp)

1.124

0.0180

0.011

ν (cs)

1.130

14.69

14.92

Approximate viscosity of water at 21C is 1 cp and 1 cs

Natural Gas Gas Characteristics Typical example

Content (%)

CH4 C2H6

93.93

LHV (kJ/Nm3) 35,822

Sp weight (kg/Nm3) 0.7143

2.42

63,736

1.3393

C3H8

0.26

91,251

1.9643

C4H10 (ISO+N)

0.002

118,637

2.589

C5H10 (ISO+N)

0

134,493

3.2143

S CO2

0 0.34

1.9643

N2 H2

3.05

1.2500

0

0.0893

He O2

0 0

0.1339 1.4286

Total

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35,428

0.7533

COMBUSTION & FUELS – Page 11/26 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-1 – COMBUSTION & FUELS

b)

Combustion

Combustion Equations for Natural Gas

•

CH 4 + 2 O2 → CO2 + 2 H 2 O

•

C2 H 6 +

•

C 3 H 8 + 5 O2 → 3 CO 2 + 4 H 2 O

•

C 4 H 10 +

7 O2 → 2 CO2 + 3 H 2 O 2

•

C 5 H 12 + 8 O2 → 5 CO2 + 6 H 2 O

•

H2 +

•

S + O2 → SO2

1 O2 → H 2 O 2

13 O 2 → 4 CO 2 + 5 H 2 O 2

Neutral Combustion Air for natural gas

•

If [x] is the volume fraction of x, the neutral combustion air is:

1 13 7 1 ⎛ ⎞ * ⎜ 2 * [CH 4 ] + * [C 2 H 6 ] + 5 * [C 3 H 8 ] + * [C 4 H 10 ] + 8 * [C 5 H 12 ] + * [H 2 ] + 1 * [S ] − [O2 ]⎟ 2 2 2 0.21 ⎝ ⎠

Rule of thumb

•

c)

9.412 Nm3/Nm3gas (for the example)

Flammability Limit flammability in air

Temp auto flame

Inf limit (%)

Sup limit (%)

in air (°C)

H2

4

75

570

CO

12.5

74

610

CH4

5

15

580

C 2H 6

3

12.5

490

C 3H 8

2.2

9.5

480

C4H10

1.7

8.5

420

Many plants experience problems maintaining the flame, during start-up when lighting the main flame or during preheating stages. During these phases, the surrounding temperature is well below the auto-flame temperature. Meaning it is relatively easy to cool the flame to cause it to “snuff” out. Further complicating the situation – operators must maintain the correct air/fuel mix in the flame zone. Outside the flammability limits and the flame “snuffs” out. Recognize that above auto flame temperature, the fuel will re-ignite as soon as it finds oxygen (so the flame can be maintained easily). The table can be used to guide engineers to designing a more robust pilot flame.

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COMBUSTION & FUELS – Page 12/26 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-1 – COMBUSTION & FUELS

Neutral Combustion Gas Products for natural gas (example) Nm3/Nm3 gas 0.999

CO2

kg/Nm3 gas 1.962

% volume

% weight

9.58%

15.25%

SO2

0.000

0.000

0.00%

0.00%

H2O N2

1.962

1.576

18.81%

12.25%

7.466

9.332

71.60%

72.51%

Total:

10.426

12.871

Natural Gas Heat Value

kJ / m 3 = 378.1 [CH 4 ] + 666.5 [C 2 H 6 ] + 958.8 [C 3 H 8 ] .

•

5. a)

Typical Preheater Exit Gas Typical preheater exit gas for different fuels

Composition of typical fuels: PET-

COAL

GAS

COKE

FUEL

SSW

OIL

ANIMAL

WASTE

CAR

MEAL

OIL

TYRES

Analysis

dry

dry

wet

wet

dry

dry

wet

dry

C [%]

86.3

68.0

74.0

85.0

60.0

51.0

69.0

68.0

H [%]

3.8

3.0

24.4

11.1

10.7

9.8

10.5

6.0

S [%]

3.7

0.6

0.0

3.0

0.3

0.6

0.1

1.5

O [%]

1.7

7.0

0.4

0.6

11.0

7.8

17.0

3.0

N [%]

1.6

1.4

0.7

0.3

0.2

11.5

3.0

0.4

Cl [%]

0.0

0.05

0.0

0.01

0.8

1.0

0.4

0.1

Ash [%]

3.0

20.0

0.0

0.0

17.0

18.3

0.0

21.0

LHV [kJ/kg]

32000

24000

49600

40000

25000

18000

23000

28000

Moisture [%]

2.0

2.5

11.0

5.0

31300

23300

49600

40000

22000

17000

23000

27100

NCA [Nm³/kg]

8.71

6.54

13.15

10.74

7.13

6.62

8.44

7.72

NCG [Nm³/kg]

8.95

6.79

14.52

11.35

7.85

7.34

9.17

8.05

NCG [Nm³/MJ]

0.286

0.291

0.293

0.284

0.357

0.432

0.399

0.297

LHVas fired [kJ/kg]

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

3.0

COMBUSTION & FUELS – Page 13/26 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-1 – COMBUSTION & FUELS

Fuel analysis at burner level. NCA=NeutralCombustionAir, NCG=NeutralCombustionGas Oxidation of metallic ashes are considered for tires (80%Fe) and SSW (20%Al, 5%Fe). Typical preheater exit gas composition for different fuels: 100%

100%

100%

100%

50%

85%

50%

70%

PET-

COAL

GAS

HEAVY

COKE

COKE

COKE

COKE

FUEL

50%

15%

50%

30%

OIL

SSW

ANIMAL

WASTE

CAR

MEAL

OIL

TYRES

COKE

CO2 [%]

28.8

29.4

24.1

28.5

25.8

27.2

25.3

28.1

H2O [%]

5.9

6.2

14.5

10.0

9.4

7.2

8.7

6.6

N2 [%]

61.6

61.0

58.0

58.8

61.2

61.9

62.3

61.5

O2 [%]

3.8

3.4

3.4

2.7

3.6

3.7

3.7

3.7

4 stage preheater, optimized conditions, Oxygen kiln adjusted to fuel, fuel analysis from table above, fuel mix in % of heat input.

6.

Flame Theory

6.1.

• 6.2.

Definition The oxidation reaction is an exothermic reaction, which can be developed either slowly or quickly: The fast reaction leads to the flame.

Flame Speed

•

In stable burner flames, the flame front appears to be stationary because the flame is moving toward the burner at the same speed that the fuel air mixture is coming out of the burner.

•

Thus risk of blow off if mixture speed>flame speed.

•

Natural gas flame speed in air: 0.3m/s and in Oxygen: 4 to 5m/s.

6.3.

Flame Radiation R = σ ε T4

6.4.

ε: flame intensity:

σ = Boltsman constant

≈

1 solid fuel

T = Flame temperature

≈

0.8 – 0.95 heavy oil

≈

0.25 – 0.70 gas

Factors Influencing the Flame Temperature

(net heat value of the fuel ) − (effect of dissociation) ( weight of comb product ) * ( specific heat of comb prodct )

•

T=

•

An increase of flame temperature can be obtained by:

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COMBUSTION & FUELS – Page 14/26 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-1 – COMBUSTION & FUELS

ƒ

Increasing combustion air temperature (ex: air temp: (80, 245, 470 C) gives flame temp (1918, 1985, 2080 C)

ƒ

Decrease primary air, increase secondary air

ƒ

Decreasing inerts: ⇒ Avoid high excess air ⇒ O2 enrichment (ex: % O2 (21, 25, 29) gives flame temp (1995, 2135, 2274 C) in case of coal, air preheated at 250 C)

ƒ

Completeness of combustion (full low heat value to be obtained): ⇒ Optimum excess air – minimize CO without too much excess air ⇒ High rate of mixing fuel and combustion air ⇒ Optimum bed depth and kiln speed – clinkering is exothermic – adds heat to flame

•

Shorten flame length

•

Water vapor in the flame decreases the flame temperature.

Fuel Requirements

•

7. 7.1.

To provide 1055 MJ of available heat (fuel is CH4 and excess air=2%) then for instance with air (21% O2) it requires 4.6/2.3=2 times as much fuel when preheat temp=245C as when preheat is 800C when flue gas temperature is 1635C

Burner Pipes Number of Air Circuits ƒ

For solid fuels, the number of air circuits determines the degree of control on the flame shape.

Single Circuit Burner Pipe

ƒ

Minimal control or very long lag times (sluggish control)

ƒ

The solid fuel has to be carried with the air.

ƒ

High velocities: Higher fan pressure requirement, higher wear in the circuit.

ƒ

Required burner tip velocity is of the order of 80 m/s. Use monotube burner calculation spread sheet for more precise estimation.

Two-circuit Burner

ƒ

Swirl + high velocity transport air.

ƒ

Additional control due to swirl but the problems of high pressure fan and high wear rate remain.

ƒ

Not common on kiln burners but gaining popularity for calciner burners (e.g. SPLC)

Three-circuit Burner

ƒ

(swirl + high velocity axial + low velocity transport air).

ƒ

The most versatile one. The solid fuel does not have to be brought at a high velocity.

ƒ

Modern designs usually feature a bluff body.

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COMBUSTION & FUELS – Page 15/26 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-1 – COMBUSTION & FUELS

7.2.

ƒ

Well designed burner gives good flame control flexibility

ƒ

Lafarge burner is the preferred type for petcoke and high AF rates, other burner types like Unitherm show good results as well.

Primary Air

Indirect System

ƒ

The primary air is usually controlled at below 12 % of the total combustion air. Figures above 12% might be necessary in case of high alternative fuel transport air.

Direct system

ƒ

No recirculation of mill exit air, the primary air can be as high as 30 to 40 % of total combustion air. All of the air exiting the mill system enters the pyro-process.

Semi-direct system

ƒ

Primary air quantity varies (usually 18 to 25 %), depending upon the incoming fuel moisture.

ƒ

To keep a constant flow (10 to 15 % of total combustion air), it is possible to send the "overflow" to the kiln hood (for the direct or semi-direct system).

Primary air impact on heat consumption

7.3.

Indirect

Semi-direct

Direct

Primary air

8-12%

20-25%

30-35%

kJ/kg

50-90

160-200

230-280

Lafarge Burner Operation and Design Basics

Example of Lafarge Burner Tip air gun axial air holes rotational circuit 2 expansion seals

coal conveying circuit central air (flame catcher)

Bluff Body (center part)

• •

Recommended minimum: 200 mm diameter Go larger (300mm and more) if more space needed for AF lines – without violating the diameter rule below

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COMBUSTION & FUELS – Page 16/26 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-1 – COMBUSTION & FUELS

6.3.2 Burner Diameter

• • • •

Ratio = burner outer diameter (steel, ex refractory) / kiln inside diameter (steel, ex refractory) Keep ratio < 12% if possible – ensures adequate space around burner for secondary air and clinker load, & minimizes excessive radiation heat transfer to burner refractory Maximum: up to 14% if required for AF. In general increase burner diameter to: ƒ Make room for AF lines (present and future)

6.3.3 Axial

• • • • •

• •

Main driver for impulse and flame positioning – increase axial flow = shorter overall flame length. CAUTION: plume length may increase with increased axial – fools operator into thinking flame length has increased – when the overall length has shortened. Minimum hole diameter 12 mm, smaller sizes known to cause tip erosion and accelerates tip build-up Maximum hole size depends on channel width of design Number of holes: 16 to 24 – as symmetric as possible. Tip speed ƒ > 325 m/s will cause metal erosion and tip build-up ƒ 275-325 m/s: recommended if high impulse target but some plants experience problems ƒ < 275 m/s preferred as long as impulse target is met ƒ Note higher tip speed means less primary air for same impulse but at higher blower kW and possibly increased burner wear (burner should last minimum one campaign) Barrel or channel speed < 20 m/s may lead to cooling problems Barrel or channel speed >35 m/s will cost you more blower kW and pressure.

Specific Impulse (Is)

• • • •

Is = sum of axial momentum from primary air, coal transport air and jacket tube air / energy rate at burner Axial momentum includes axial air, coal channel transport air and axial vector of swirl air When “Is” ratio is held roughly constant, flame length is roughly constant Momentum impulse: where: M *V

Is =

Q

-

Q = ki ln ( heat power ) inGJ .h −1

-

M = primary airflow ( in the axe ) in kg .s −1

-

V = Air Speed in m.s −1

Operation Rules of thumb Specific impulse

Typical

Fuel Oil

1,2 N.h.GJ-1

Coal

1,5 N.h.GJ-1

Coke and AF

1,8 N.h.GJ-1

Design: > 2.2 N.h.GJ-1

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COMBUSTION & FUELS – Page 17/26 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-1 – COMBUSTION & FUELS

WARNING: other factors might cause “rule of thumb” values not to work. The main ones are kiln geometry and the amount of kiln draft (determined by kiln inlet O2). To determine optimum “Is” for a given kiln use MAP/MAS calculation and finally feedback from operation and quality parameter. 6.3.4 Swirl or Radial

• •

Affects flame diameter and partly flame length Used to optimize sulfur retention in clinker – but when improperly used can risk brick life rapidly

Where:

Rotational moment / axial moment ratio Vry

I θr = I xr t g α I - θ : tangential impulsion

-

Rot. circ. velocity: Vr

Vrx rg

where:

I θ r = Qmr . Vry Ix = Σ

•

i

Ix

2Qm

Πρ mΙχ

•

i

The gyration radius defines, on the basis of the respective radius of the rotational circuit at the burner pipe tip. - rg = 2/3 (re3 – ri3) / (re2 – ri2) - re = external radius - ri = internal radius

where: - Qm = The total mass flowrate of the air injected

The equivalent diameter of the flow is given by:

De =

- I xr : rotational circuit axial impulsion - α : swirl angle (usually between 20 and 35 degree: smaller for long dry kiln)

Iθ r r g SW = I x . De

- ρ m = The average specific gravity of the air - Ιχ = The total axial impulse

Ιχ

Operation Basic Rules of thumb Swirl Fuel, coal, coke, AF

• • • •

•

Long Kilns

Short Kilns

0,02 to 0.08

0,08 to 0.15

Up to 0,2 can give good results with high S petcoke or high AF rates. However experience suggests that the higher the thermal load or SHC, the lower the kiln’s ability to accept strong swirl. Or higher the SHC, requires less aggressive swirl angle (minimize risk to brick). Flame shape (touching the bricks) might require swirl < 0,1 even in short kilns. Swirl # potential increases with increasing swirl angle. Suggested angles: Short kilns: 30° to 35° Long dry kilns:

20° to 25°

Long wet kilns:

15° to 20°

Swirl MUST rotate in same direction as kiln rotation (opposite endangers brick or makes for very sensitive swirl control)

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COMBUSTION & FUELS – Page 18/26 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-1 – COMBUSTION & FUELS

6.3.5 Transport (coal/coke fuels)

•

Tip speed:

o o o o

> 40 m/s: causes very long flame – even strong impulse may not shorten flame > 35 m/s: causes long flames, high operating backpressures 25-35 m/s: recommended < 25 m/s: not recommended – leads to poor fuel distribution in channel, skews flames

•

Coal channel annulus must be centred and symmetrical – otherwise flame may skew. Spacers are critical. Suggested tolerance: channel width one side vs. channel width on opposite side must vary < 15%

•

Velocities must be steady – no pulsing. Pulsing can be detected by transport line pressure cycling and cycling frequency should match O2 signal cycling (use variogram to prove it)

•

Fuel density in transport line 3-5 kg/Nm3, up to 7 kg/Nm3 possible

6.3.6 Miscellaneous Natural Gas Nozzles

•

Generally design system such that gas does not reach sonic velocities (mach 1 occurs at lower velocities for natural gas vs. air). If gas speeds are = mach 1, can’t control flame. (Also causes high pitched loud noise). Exception: The special designed Lafarge high impulse 100% gas burner is operating supersonic.

•

For a given nozzle design, find a back pressure that correlates with a good gas flame. Hold to this back pressure (approx.) as fuel rate changes by adjusting nozzle opening (where adjustment is available)

Liquid fuel injection: use of injectors :

•

MY type: 40 bars: when operation is stable.

•

ZV2 (assisted pulverization): between 2 and 20 bars: when wide range of flow variation.

MAP/MAS Developed originally for AT precalciners where draft through the kiln can strongly stretch the flame. Caution: MAP/MAS is a calculated estimate – so ideal target value is kiln specific. MAP = momentum air primary MAS = momentum air secondary Lafarge Burner Tool carries calculation requiring input of secondary air amount and temperature from a heat balance. Operation rule of thumb for coke flames (or low VM fuels and/or high S fuels) in short kilns

•

MAP/MAS ~ 2.0-2.1 suggested target – works in most applications – good starting point if uncertain. Has yielded good flame control, good sulfur retention in clinker, improved Alites

•

MAP/MAS > 2.3 may be necessary, but take care, flame might be too short causing brick damage – watch shell scanner closely).

•

MAP/MAS < 1.5 very lazy long flames

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COMBUSTION & FUELS – Page 19/26 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-1 – COMBUSTION & FUELS

From experience and observations (LNA)

•

MAP/MAS 1.7-1.9 may be better suited for long wet kilns or kilns with high thermal loads (e.g. production of oilwell clinker)

•

MAP/MAS 1.5-1.8 may be better suited for very easy burning fuels (e.g. very high %VM coal) or where a mix of fuels is used where one component is extremely easy to burn (e.g. fuel oil and coal)

7.4.

•

Burner Alignment Strongly recommended starting point for modern high impulse 3 circuit burner: ƒ Burner axis should lie on the axis of the kiln (in centre of the kiln and parallel to kiln slope) ƒ Use laser alignment method ƒ Flames from high impulse burner can be sharp and short. Misalignment can drive flame into brick or material load. ƒ Final alignment setting depends if flame needs to be centred (real objective) – e.g. fuel channel can have a slight skew – compensate with burner alignment to keep flame centred Remark: Direct fired burners (most mono tube burners) do not have sufficient impulse – therefore flame is always lazier. Such burners cannot be aligned on the kiln centreline. Goal is to centre the flame. ƒ Burner position inside kiln: ƒ Design: Should at least allow flexibility to position -20cm flush to the kiln (cold) to 70 cm inside. ƒ Operation: Generally recommended: 0-10 cm inside the kiln If severe snowman formation or increased thermal stress at lower transition brick defensive measure is to insert burner tip deeper into the kiln.

Refer to ‘How to Align Burner’

8.

Combustion Success Criteria

When the indicators below are met simultaneously, good combustion is achieved. For some parameters it will be impossible to reach with alternative fuel (example kiln inlet CO in case of whole tyre firing), still the values below remain the reference for good combustion. The indicators are divided in 3 categories: + Combustion Quality + Combustion Stability + Plant Specific

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COMBUSTION & FUELS – Page 20/26 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-1 – COMBUSTION & FUELS

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COMBUSTION & FUELS – Page 21/26 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-1 – COMBUSTION & FUELS

9.

Fuel Grinding and Dosing Solid Fuel Grindability

9.1.

•

The Hardgrove Grindability Index (HGI) indicates the ease of grinding solid fuel.

ƒ

It is the % passing 74μ after grinding for predetermined amount of time

•

Range for coal: 45 to 70 HGI Range for coke: 30 to 50 HGI

•

HGImix = x * HGI coal + y * HGI coke.

Bowl Mill (Raymond) Capacity

Fuel Grindability (Hardgrove)

100

80

60

Passing 75um (#200) 40

20 0.6

90% Raymond 85% Raymond 80% Raymond 75% Raymond 0.8

1.0

1.2

1.4

Mill Capacity Factor

ƒ 9.2.

0.10 mill capacity factor for 5 HGI

Solid Fuel Fineness

(see also Les Cahiers Techniques Combustion and How To burn petcoke) General guideline for fineness – minimum expectation. For other process reasons it may necessary to grind finer but also increases safety risk. % R at 90μ = 0.5 x VM for the main burner, and % R at 200μ = 0.05 x VM For calciner with low residence time need to grind finer (up to %R at 45μ = 0.5 x VM) Rules of thumb

•

5% more passing at 74μ yields to 15-20% less mill capacity.

•

Addition of HES: 5% production increase at constant fineness.

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COMBUSTION & FUELS – Page 22/26 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-1 – COMBUSTION & FUELS

Relationship: Burning Time & Particle Size Burning Time (seconds)

10 Combustion Temp. = 900°C

1 Combustion Temp. = 1500°C

.1 .01

9.3.

•

.1 Diameter of coal particle (mm)

1

Dosing Dosing should insure a regular and steady feeding of the burner. Measurement precision of +/0.5% obtainable with Pfister or Schenck Coriolis. Coal concentration 3-5 kg/Nm3 of transport air. Good dosing (control) means good combustion stability. Good combustion stability is characterized as follows (from Technical Agenda Fuel Flexibility):

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COMBUSTION & FUELS – Page 23/26 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-1 – COMBUSTION & FUELS

9.4.

Safety Considerations

•

Safety practices should be implemented and maintained by Process department

•

Raw solid fuel storage recommendations

ƒ

4 months if VM<15% (anthracite coals and petcoke)

ƒ

2-3 months if 15%
ƒ

1-2 months if 25%
ƒ

1-4 weeks if VM>36%

Recommendations (refer to Coal Grinding Safety Technical Agenda for details): Measurement Location

Low Risk Limit

High Risk Limit

Storage Pile External

55 C

50 C

Raw Silo (lower cone)

55 C

50 C

Raw Silo (top) CO

1500 ppm

1000 ppm

Mill Inlet Temp

250-275 C

220 C

Can be +/- 5 C of these limits German Lignite much higher risk

Comments

Mill Inlet O2

13-15 %

9-11 %

Mill Inlet CO

500 ppm

500 ppm

Mill Outlet Temp

90-100 C

80 C

Can be +/- 5 C of these limits – according to res. %H2O

5C

5C

HIHI 10 C – temp

Filter Differential Temp

Above normal operating point (from PH tower)

determine if outlet temp > inlet

Filter Outlet O2

13-15 %

9-11 %

May need to add air inleakage

Filter Outlet CO

500 ppm

500 ppm

Above normal operating point

Filter hopper Temp

90-100 C

80 C

PF bin (top) Temp

90 C

80 C

PF bin (cone) Temp

90 C

80 C

1500 ppm

1000 ppm

PF bin CO

As per requires residual %H2O in ground fuel

Also 50 ppm/min rate of rise maximum

Note: High risk fuel and/or operation are defined by volatiles >36% air dry basis or over grinding of medium volatile fuels to less than 50% VM retained on 90μ

9.5.

Fuel Grinding Mills

•

Feed size: 0-50mm, moisture content: 10-15%, exhaust gases dust load: 500-600g/m3.

•

Hot gases temperature 250-400C, dew point: 20-70C, exhaust gases temperature: 80-100C.

•

Moisture content in the blasted fuel below 1%. Hammer mill

Tube mill

Roller mill

20-30

25-30

10-13

Lifetime wear part hours

500-1000

25000-40000 (Liners)

3000-5000

Drying capacity % H2O

0-15

0-15

0-20

Type of grinder Power Consumption kWh/t

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Ring ball mill (Babcock)

9000-12000

COMBUSTION & FUELS – Page 24/26 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-1 – COMBUSTION & FUELS

Rules of thumb: •

Mill sweep : 1.7 to 2.2 Nm3/kg fuel

•

Drying efficiency : average 1200kcal/kgH2O for a residual moisture of 0.5 to 1.5%

10. References Cement Portal

•

How to Align a burner

•

How to start up & optimize a burner

•

Lafarge Burner calculation Tool

•

How to burn petcoke

•

Technical Agenda Study Coal Shop Safety

•

Combustion Manual (post Sevilla 1997)

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COMBUSTION & FUELS – Page 25/26 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-1 – COMBUSTION & FUELS

My notes:

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COMBUSTION & FUELS – Page 26/26 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-2 – ALTERNATIVE FUELS

2-2. Alternative Fuels

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ALTERNATIVE FUELS – Page 1/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-2 – ALTERNATIVE FUELS

Table of Contents 1.

Alternative Fuel Categories........................................................................3

2.

Alternative Fuels and Industrial Performance..........................................4

3.

2.1

Lafarge Performance...................................................................................... 4

2.2

AF Performance Outside Lafarge................................................................... 4

AF Potential for Preheater and Precalciner Kilns ....................................5 3.1

Challenges of AF properties: .......................................................................... 5

3.2

Achieving High AF Firing Rates...................................................................... 6

4.

Liquid AF......................................................................................................7

5.

Sludges ........................................................................................................9

6.

Solids including Biomass.........................................................................10 6.1

Tyres ............................................................................................................. 10

6.2

Solid Shredded Waste .................................................................................. 13

6.3

Biomass ........................................................................................................ 17

7.

Solid AF Main Burner Firing.....................................................................18

8.

Reference AF Documents.........................................................................19

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ALTERNATIVE FUELS – Page 2/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-2 – ALTERNATIVE FUELS

1.

Alternative Fuel Categories Name (CKHC) LCS (Liquids Containing Solvents Low flash point)

L i q u i d s

Used Oil

Waste water

Common names

Comments & BRS code

Liquids containing one droplet of Solvents, Recycled Liquid Fuel solvent as it requires similar (RLF); Fuel Quality Waste (FQW), equipment (safety issue due to low Combustibles Liquides de flash point) Substitution (CLS); G3000 (Lafarge Ciments France) BRS - CR119X, CR130X, AR627X

Spent oils

G2000 (Lafarge Ciments France)

Other Liquid Alternative Fuels

No net recovered heat value so different category from other liquids.

Category to report all the rest of liquids that are not reported in the other 4 liquid categories. CR121X, CR132X, AR629X

Tyres

Tires

Spent co-products of petrochemical refinery, originally commercialized to dissolve or extract impurities from chemicals. Used liquids are collected for regeneration, re-use or disposal. LCS are residues from 2nd and 3rd life cycles of fresh solvents. Paint industy, chemical & pharmeceutical, adhesives or rubber manufacturers, metalworking and cleaning services.

Unique waste market context. Often Includes: classified as haz waste (like solvents) - black oils from the evacuation of thermal engines; but with separate, less restrictive - light oils from gear boxes; regulations for energy recovery. - oils used for the lubrication of cutting instruments. Pure vegetal oil are reported under "Biomass ". CR118X, CR129X, AR626X

CR157X, CR136X, AR637X

Other pumpable Materials (High flash point)

Definition

Unique waste market context (market, regulations)

Liquids with very low or no calorific value. Includes effluents from industrial processes, and liquid from waste water treatment plants.

Liquid wastes, not classified as "LCS (solvents)" , "used oils" nor "wastewater" . Petroleum refineries and petrol stations wastes (e.g. hydrocarbon sludge; refuse from hydrocarbons storage; sludge from API settling tanks; emulsions); sludge from ultra-filtration of cutting products; kormul; cosmetics industry (waste, spoiled products, paints); lithographic industry ink, etc.

Used tyres (whole tyres, shreds or chips); rejects from the tyres production; deformed tyres; off-spec. tyres.

CR122X, CR133X, AR629X SRF (Solid Recovered Fuel), ASF (Alternative Solid Fuel), PDF (Plastic Derived Fuel), DIB /DSB (SSW) (Déchets Industriel /Solid Banal), Solid Shredded ASB or Fluff (Germany, Austria), Waste PASr (Poland), ASR (Automobile shredder residue), RBA (Residue de Broyage Automobile)

Refuse Derived Fuel (RDF) or CDR (Italy) sometimes used to indicate origin is treated muncipal solid waste (MSW) but no accepted naming convention in literature.

CR123X, CR134X, AR631X S o l All other pre-treatment than the ones (ISF) Impregnated sawdust, Resofuel, i used for liquid or shredding/sorting Combustibles Solides de Impregnated Solid d Substitution (CSS), PASi (Poland). Fuel s CR124X, CR135X, AR632X

Other non pumpable solid

Other solid alternative fuels

Tar and other solid chemicals which do not fit into other categories CR125X, CR144X, AR634X

Energetic ARM

Category to report on the energy used by the kiln from an ARM. Therefore, only the calorific eARM, Other hydrocarbons / Fossils contribution (%) will be reported. CR120X

Animal meal

B i o m a s s

MBM (Meat and Bone Meal)

CR115X, CR126X, AR623X

All solid residues with calorific value (PSR) from the Waste Water treatment Sewage sludge, Processed Sewage process. Processed Pellets (PSP) Sewage Residue CR116X, CR127X, AR624X

Other 100% carbon neutral fuel. Biomass

Other biomass CR117X, CR128X, AR625X

© Copyright 2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

Non-hazardous shredded industrial and commerical waste. Includes plastics, paper, cardboard, synthetic textiles, construction and demolition waste (C&D), etc... Also sorted, dried or otherwise pretreated fraction of the household wasteor MSW (muncipal solid waste). Often has significant biomass content for CO2 credits

Processed solid hazardous fuel - a blend of "difficult-to-handle" waste and absorbents. Typical input comprises pasty residues with difficult properties (paint sludge, glue, grease, ...) and heterogeous solids (resins...) with a "carrier" solid (e.g. sawdust) This category regroups all solid wastes that are not classified as "Tyres" , "Impregnated Solid fuel" , "Energetic ARM" nor as "Shredded Solid Waste" . An example is the TDI tar, a residue whose origin is the isocyanate toluenes manufacturing process. If the calorific value is >12 GJ/T, not an eARM - must reported in another AF category. ARM whose calorific value contributes to the plant's AF substitution. Only total calorific input (%GJ) reported in this category, volume and gate-fee are reported under appropriate ARM category. Meat and bone meal, blood meal, feather meal, poultry meal, bone meal and fish meal. Animal fat is classified as Biomass and not as Animal Meal. Solids removed at (municipal) wastewater treatment plants (WWTP). Final quality depends on the nature of the wastewater and the process. It can be used in cement kilns in the form of sludge, filter cakes, dried material or pellets. All wastes of organic matter - husks from agricultural products (sunflower, rice, palm tree), vegetal oils (lipix), wood wastes, animal fat, mycellium, moinha, spoiled seeds (with or without pesticides), and natural textiles. All the waste of this category have to be 100% carbon neutral.

ALTERNATIVE FUELS – Page 3/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-2 – ALTERNATIVE FUELS

2. 2.1

Alternative Fuels and Industrial Performance Lafarge Performance

Kiln Performance with >25%AF (CKHC 2009) %AF 2009 FREDONIA PAULDING RETZNEI KARSDORF CIZKOVICE PLN MEDGIDIA FRANGEY LE TEIL (White) MALOGOSZCZ HOGHIZ MANNERSDORF CAULDON WHITEHALL WOESSINGEN VDZ HARLEYVILLE ARCOS Carriere SUGAR CREEK KUJAWY SPLC LA MALLE SOETENICH DUNBAR LE HAVRE BULACAN SAGUNTO (Grey) TULSA

2.2

93.5 87.8 77.0 67.8 65.0 62.3 48.9 47.0 46.3 46.1 45.5 41.3 40.2 38.2 38.1 37.7 37.2 35.5 34.7 33.3 33.0 33.0 31.9 31.2 29.8 29.5 27.6 25.9

% % LCS % % used Other % tyres Solvent wastew % SSW oils pumpa s ater ble

93.5 86.7 4.7 19.6 12.6

0.6

0.2

0.0 0.3

45.2 0.2 0.4

5.8

0.0 0.0

17.5 3.9 1.1 1.3 0.8 0.1

0.3

0.5 0.9

14.1 0.0 8.6 1.7

0.5

21.4 8.6 13.3 36.7 10.3

11.5 7.0 30.8 27.9 1.4 3.6 8.8 18.0

2.7

6.2 1.1

3.8 10.0 7.0

% PSR % % % MBM (sewag biomas % coal % coke eARM e) s

23.5 24.6 17.1

0.6 14.1

1.1 3.7 21.4 6.2 37.6 1.7 10.3 35.9 6.1 22.8

11.6 5.3 8.1 32.2 2.3

9.5

0.4

0.1 30.7

15.8

2.5

0.7

53.1 0.5 2.9

0.4 7.7

0.0

14.9 16.0

2.8 0.0 0.4

54.8 53.0 42.0

0.8 13.5

8.4 6.0

17.5 16.8 4.9

32.0 29.1

0.9 1.9

2.4

12.4 0.0

0.1 17.6 4.8

26.9 22.6 4.0

1.3 5.9

% Other non pumpa ble

2.8 1.2 14.6 15.0 0.1

22.2

0.1

% ISF

2.3

18.1 2.8 3.6

2.9 11.5 17.1 0.2

61.4

3.9

60.1 67.7 0.8 59.1*

0.4 28.1 3.6 6.4

28.7 42.5

50.4

2.9 11.5 22.2 0.0 0.0 36.0 50.7 42.6 25.9 0.6 54.1 3.2 6.3 15.2 58.6 48.4 0.0 64.5 35.0 23.9 65.3 63.2 0.0 0.0 62.9 11.4 71.5 19.9

% oil / HVF*

0.8 5.1 1.7 10.4 4.4/ 21.3* 0.3 0.6 0.5 4.7 2.6 12.0* 0.0 0.1 0.3 1.7 2.3* 8.0 1.1 6.6 0.1 0.9

AF Performance Outside Lafarge

• German cement industry average 1 (2006-08): +50%AF, (2009): 58% o SSW (industrial+commercial) 53%, tyres 9%, sewage sludge 9%, MBM 8%, municipal 8%, • • • • •

1

oil sludge 6%, solvents 4%, waste oil 3% Heidelberg ENCI Maastricht – 98%AF o Long dry kiln, 2 stage preheater, no mid-kiln firing o RDF, biomass, textiles, sewage sludge, MBM – all non-haz except glycol-bottoms Heidelberg Gorazdze (Poland) – annual 50%, sustained 83%AF o 47% Precal (SRF, whole tyres), 36% Main (SRF) o 6000 TPD, FLS 4-stage PH, Modified with Technip-CLE Minox RSP, bypass Heidelberg Beckum (Germany) – 75% AF o Main burner : 12,5 T/Hr SSW ◊ 55% + 5% MBM, Back-end : 15% Whole tyres o 1MTpa, PH 4 stages, bypass Cl 4%. PMT Wietersdorf (Austria) – 74%AF o 50% Precal (SRF, MBM), 24% Main (SRF, PSP) o 1770 TPD, ATEC tower, precal, bypass Holcim Lagerdorf (Germany) – 70%AF o Distillation residues, MBM, RDF (high Cv, low Cv, roof felt), 100%AF in precal achieved

Source VDZ reports

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ALTERNATIVE FUELS – Page 4/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-2 – ALTERNATIVE FUELS

o 4500 TPD, 3-stage, 2 string PH with inline Prepol MSC precal, Modified precal, bypass • Dyckerhoff Lengerich (Germany) – 51%AF o 34% Precal (MBM), 17% Main burner (MBM, SRF, RLF) o 3700 TPD, 2 string 6-stage PH with FLS-ILC, bypass

3.

AF Potential for Preheater and Precalciner Kilns

General The quality of alternative fuels differ significantly, depending on type, origin and preparation. When using AF with high heat value, small particle size and low Chlorine we could reach 100% AF rate in most of our kilns, but high quality AF are becoming increasing more difficult to source or have a fuel cost similar to fossil fuels.

3.1

Challenges of AF properties:

1) Low Heat Value Fuels: Calciner or Preheater Back End Firing is less sensitive to low heat value fuels. In an optimised calciner a heat value of the fuel mix down to 15000 kJ/kg (LHV as fired) can be managed, in the back end down to 13000 kJ/kg (LHV as fired). The main burner requires higher heat value to maintain a stable sintering zone, in an optimised kiln firing a fuel mix down to 21000 kJ/kg (LHV as fired) can be managed.

2) Particle Size: a) Whole tyres: Up to 30% of total heat in an optimised preheater back end, up to 7% of total heat in a calciner kiln (higher rates would require specific equipment like a hot disc). b) Shredded Tyres / SSW / Biomass Successful firing of shredded AF requires a shred size compatible with the gas velocities in the precalciner / riser. Whilst the gas velocity at the shred injection point can be increased to minimise the fall through to the kiln inlet, the main riser / precalciner gas velocity is a characteristic of the plant design. Shredded AF is more easier to burn in a vessel calciner than in a riser duct design due to the inherently lower gas velocity and hence longer fuel residence time. However, separate line calciners can be difficult since any fuel / ash drop out will tend to block the tertiary air duct. Firing of shredded fuels should be made into a rising gas stream, i.e. avoid firing into downdraft precalciner / hot spot due to drop out into the kiln inlet. Although in general precalciner gas residence time of greater then 2-3 seconds has little effect on the combustion of shredded fuels, a higher residence time will help to achieve NOx reduction and burnout of CO.

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ALTERNATIVE FUELS – Page 5/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-2 – ALTERNATIVE FUELS

c) SSW for Main Burner A manageable size at the main burner for SSW: 95% < 30x30x2mm ; (<25x25x1 can boost the AF rate at the main burner above typical figures as shown in the table below ; <20x20x1 is not giving added value to agglomeration of the foils)

3) High Chlorine Fuels: A total Chlorine input (raw mix and fuel) of 250 g/t up to 350 g/t cli can normally be managed without a bypass. The reachable Chlorine input without bypass is plant specific, depending upon the mastery of the process, preheater cleaning, kiln type, raw mix burnability, preheater design and clinker granulometry. An important parameter is the Sulphur level, high Sulphur in addition to Chlorine is critical for build up formation and reduces the manageable Chlorine input. Chlorine input above the plant specific limit can only be managed with a bypass – the possible Chlorine input then depends on bypass size and related dust management.

4) Other Impurities Ash coming with AF might become a limiting factor for use. Example is Phosphorus in animal meal. The Phosphorus in clinker typically should not exceed 0.5% due to cement quality reasons (loss of workability and early strength). Even harmless ash like iron in tyres might become a limiting factor in specific cases or tyre feeding interruption can become critical for clinker quality. Compatibility of high ash AF with raw mix and clinker quality / regularity needs to be checked for the specific case.

5) AF with high fluctuation: Fluctuation in AF quality (mainly heat value) can be better managed in a calciner where automatic temperature control gives a direct response and allows correction by a more stable fuel. Fluctuation of other properties such as size or chlorine level can be very problematic to manage. AF used at the main burner needs to be more consistent in its properties.

3.2

Achieving High AF Firing Rates

1) Preconditions Æ AF Permit and well mastered stakeholder relationship Æ Well mastered plant (optimised operation, well maintained instrumentation, good process follow up,...) and reasonable equipment (grate cooler with fixed inlet,…). Æ Build up control on high level (meal curtain, small design improvements done, air canon arrangement optimised, tools like Cardox and multi port air canons in place, systematic optimisation of cleaning procedures in place, ...) Æ Kiln Oxygen maintained on target (might limit kiln output) Æ Well Mastered Fuel Introduction (stable and reliable fuel dosing, optimised position, good management of fuel interruptions, ...) Æ High level control of quality and operation parameters (hot meal monitoring, FeO clinker, Rietveld,...) Æ Reasonable AF market, AF input control and management of supplies Æ High momentum kiln burner with proper jacket tube design

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ALTERNATIVE FUELS – Page 6/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-2 – ALTERNATIVE FUELS

Æ Emissions controlled and limits kept (NOx, CO, Hg, ...) Remark: Several of these preconditions have a time factor and need plant specific optimisation; going to maximum AF rates for a kiln system needs a step approach of 2 – 3 years.

2) Levers to boost AF Usage Low investment but increased operating cost: Æ Injection of Oxygen at the main burner (KAR example). Æ Injection of air in the kiln back end static part (Preheater kiln only, MAL and SAG example). These options should be only used when the AF firing is already optimised. Air injection in a non optimised system (Oxygen not on target, fuel poorly distributed, ...) might still increase AF but with higher costs compared to optimising. Significant investment: Æ Better AF preparation – on site or via supplier (finer shredding, sorting facility to reduce Chlorine, drying facility for AF, homogenisation of AF,...). Æ Installation or upgrade of a bypass. Æ Enlargement of calciner or kiln riser to increase residence time. Æ Upgrade of burner or fuel dosing system. Æ Investment in emission reduction (SNCR, SCR, Hg control by dust management) Æ “Cadence“ air injection on the kiln rotating part (REI, TUL example).

3) Achievable AF rates (2 years in a well mastered plant) : All figures in % of total heat consumption

Preheater kiln (75/25 split) Main Burner

Small Size SSW or Biomass (<30x30x2 mm)

Back End

20 - 25

Calciner Kiln (40/60 split) Main Burner

Calciner

8 -10

40 - 50

Medium Size SSW, Biomass or Shredded Tyres (<50x50x8mm)

-

10 - 20

-

20 - 50

Whole Tyres

-

20 - 25

-

5-7

Liquid Fuels

50 - 75

20 - 25

30 - 40

50 - 60

4.

Liquid AF

•

The most important characteristic for liquid AF is flashpoint, as this defines equipment and system safety requirements. One “drop” of low F.P. solvent makes used oil a low flashpoint liquid.

•

Processing (handling, blending, storage, dosing) and combustion issues and solutions are generally similar for all types liquid AF, and independent of waste origin (solvents, oils, etc).

•

Cv, moisture, %solid, solids size, viscosity and chlorine are key characteristics which indicate potential process impact

•

Characteristics for good liquid AF combustion (Ref: Fuel Flexibility TA) o Water content < 5-30% +/-5% variation from avg o Solid content: <45% +/-5% variation from avg, < 5mm o Viscosity: 150 cps

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ALTERNATIVE FUELS – Page 7/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-2 – ALTERNATIVE FUELS

Example Paulding Waste Fuel Analysis (Fuel blend to kiln) – 194 analysis (2004)

Average Std Max Min

HHV kJ/kg 26 231 1078 29308 23725

Average Std Max Min

Zinc ppm N.D. N.D. N.D. N.D.

Ash (%) 7.0 1.10 8.7 3 Chromium ppm 99.9 101.21 978 27

Visc (cps) 68.1 28.09 165 8 Barium ppm N.D. N.D. N.D. N.D.

Chlor (%) 1.4 0.30 2.26 0.69

Solid Sp. Grav (%) (g/ml) 16.2 0.9 4.99 0.02 30 0.97 2 0.86

Lead Cadmium ppm ppm 146.8 6.2 78.23 5.79 529 57 38 1

Silver ppm N.D. N.D. N.D. N.D.

Sulfur Water (%) K. Fischer 0.3 19.4 0.14 1.96 0.7 24 0.06 12.5 Antimony ppm N.D. N.D. N.D. N.D.

Thallium ppm N.D. N.D. N.D. N.D.

PCB ppm N.D. N.D. N.D. N.D. Beryllium ppm 3.5 2.64 9 2

pH 6.3 1.23 9 4

Benzene (%) 0.7 0.55 1.2 0.2

Arsenic Mercury ppm ppm 7.4 0.9 4.49 0.68 23 3.6 2 0.1

•

Liquid AF, especially waste solvents often contain high water, which becomes the driver for low heat value as fired. Waste solvents @ 20%H2O = 25 GJ/T.

•

Used oil is generally “cleaner” than waste solvents, as oils are usually regulated for halogens (Cl) and sulphur content. Waste oils often have special waste legislation consideration and may or may not be considered hazardous. Gate “cost” now often approaches or exceeds coal.

•

Self sustaining flame requires LHV = 13-15 GJ/T. US-EPA (1991) 1 required >11.6 GJ/T (5000 Btu/lb) to be considered as energy recovery and not as waste disposal.

•

Energy can be recovered if combustion gas T of the AF mix exceeds the exit gas T. If AF cannot reach the required combustion T (precal or main flame) then additional supporting fuel of higher CV would be required but from a thermodynamic perspective heat could still be recovered o 70% water + 30% pure solvent can obtain 1350C (main flame T) o 84% water + 16% solvent could obtain 900C (preheater T)

•

Examples Liquid AF Ultimate Analysis

1

WASTE OIL

WASTE SOLVENTS

C [%wet]

74.9

40.0

H [%wet]

11.9

10.4

S [%wet]

0.9

0.2

O [%wet]

12.1

46.2

N [%wet]

0.1

0.1

Cl [%wet]

0.1

0.1

Ash [%wet]

0

3

LHV as fired [kJ/kg]

36 600

14 600

Regulatory definition of energy recovery since changed

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ALTERNATIVE FUELS – Page 8/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-2 – ALTERNATIVE FUELS

Solvents - Reception, Pumping •

Paulding & Fredonia: 80-95% annual substitution with high solids and 30% water content

ƒ Unloading: recessed impeller turbine pumps, gear pumps for start ups/highly viscous matter ƒ Unloading station: No filters, only knock-out boxes to protect down stream pumps against large contaminants (e.g. bolts, stones). Multi-step in-line grinders e.g. PDG – two step (< 8 mm, < 5 mm) ensure all solids or sludge matter is ground for liquid suspension blending. These rotating shredding knifes are appropriate even for hard foreign bodies (such as pigments, abrasives, small metal, etc).

ƒ Dosing: recommend recessed centrifugal pumps for transfer and dosing. Simple, robust against any foreign bodies and solvents resistant (no elastic parts directly exposed to the flow media).

ƒ Flow-meter: Coriolis Nozzle for solvents with high solids content •

5.

Inner liquid pipe (up to 550 cSt viscosity) with outer compressed air (30 Bar) with swirl vanes coming to single outlet (12 mm)

Sludges

•

Sludge is not a CKHC AF category. Volume may be reported under “High Viscosity Fuel (non-AF)”, “AF other pumpable material” or “PSR - processed sewage residue”. PSR includes filter cake, dried and pellets.

•

Plants are burning sewage and petroleum sludges, whose viscosity exceed conventional pumps.

•

Current equipment recommendation is Putzmeister double plunger pump. Used for concrete and other sludge applications, these pumps are not subject to normal limitations on particle size or back pressure (viscosity, line distance or height).

•

Injection location for low Cv or eARM is either onto the riser shelf which will carry the material in to the kiln by the meal return flow into the rotary kiln or higher Cv material is best injected downwards from the highest point (cases of an inline calciner). A nozzle designed to assist dispersion has been successfully tested in Medgidia, Romania.

•

Sewage sludges have specific health risks that need to be considered for those in the workshops.

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ALTERNATIVE FUELS – Page 9/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-2 – ALTERNATIVE FUELS

6.

Solids including Biomass

•

Composition of a solid AF depends on the origin of the waste and its pre-treatment. However combustion behaviour can be defined by a few key characteristics independent of origin: size distribution, Cv, moisture, ash, volatile content, Cl, 2D/3D, variability). Thus similar characteristics, similar impacts shredded tyres, construction debris, fluff, impregnated solid residues, biomass, etc

•

Backend injection: Objective is to locate injection point to create longest AF particle path in presence of high available O2; want best compromise between 2D (films, fluff) which can be carried over and heavy 3D which will drop-out onto riser slope (high CO). See comments on tyre chip burning

o

•

6.1

Good backend combustion is a function of particle size/ density, gas velocities and injection location. Ideal situation is calciner gas velocity of 4-6 m/s (vessel precalciner) which limits carry-over and 35-40 m/s at riser inlet which will re-entrain solid AF thus create a condition of semi-suspension or recirculating fuel path.

See “Guidelines AF Potential” and “AF Firing Main burner, SSW benchmark”

Tyres

Tyre Composition

•

1

Typical Ultimate Analyses Typical HHV (dry), GJ/T LHV (dry), GJ/T LHV - 0.6% moisture LHV - 5.0% moisture % Moisture - AF Dry Basis % Ash % Carbon % Hydrogen % Nitrogen % Sulfur % Oxygen (diff) % Chlorine Total

26-36 24-32

Cauldon, UK Car + light truck 25.3

31.4 30.2 29.9 28.8 Inside = 0.6%, Outside = 5.0%

0-5% 18 - 25 % 60 - 70 % 5-7% 0.3 - 0.5 % 1-2% 3 - 10 % 0.1 - 0.3 %

North America (CTS) Car Truck 33.0 31.8

21.5% 61.0% 5.4% 0.4% 1.0% 10.7% 0.03% 100.0%

16.8% 73.0% 6.7% 0.4% 1.3% 1.6% 0.3% 100.0%

20.0% 70.2% 6.4% 0.4% 1.3% 1.5% 0.3% 100.0%

1

Higher Cv and carbon content is systematically reported in North America than Europe, due to different tyre formulation and more tread (rubber content) on rejects. “Cauldon” data is multi-sample analysis of tyre chips (Aug 2000). CTS is combined literature and lab analysis (3 plants, 9 samples). CTS calculated Cv from analysis (CHON + ash) and compared to lab values (+/- 3%). CTS assumed 4.5% non-wire ash, rest of ash is wire. Wire assumed 99.5% iron.

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ALTERNATIVE FUELS – Page 10/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-2 – ALTERNATIVE FUELS

• Typical Ultimate Analysis of Car Tyres including Ash Analysis (Europe) CAR TYRES

C [%dry]

68.0

SiO2 [%]

11.0

H [%dry]

6.0

Al2O3 [%]

1.0

S [%dry]

1.5

Fe2O3 [%]

1.0

O [%dry]

3.0

CaO [%]

3.0

N [%dry]

0.4

MgO [%]

2.0

Cl [%dry]

0.1

K2O [%]

1.0

Ash [%dry]

21.0

Na2O [%]

1.0

28 000

Femetallic [%]

80.0

LHV dry [kJ/kg]

•

ASH ANALYSIS

Trace Analysis - Blic Bruxelles Basel Convention series No. 00/003

ƒ Recommended reference for stakeholder communication (general but published by an international agency)

ƒ (Te+Sb+Se+V+Cr+Ni+Hg+As+Pb+Co+Sn) < 0.1% (1000 ppm). Cu <0.1%; Co <0.05%; Pb <50 ppm; Cd <3 ppm; Cr <100 ppm; Ni <200 ppm; PCP, PCP-PCT: Non-Detect (<0.5ppm) by w

•

Trace Analysis Measurements (Cauldon, Rugby Cement 1 )

Cr As Be Cd Co Cu Mn Ni Pb Sb Se Tl V Zn Sn Hg

µg/g, ppm (dry basis) Cauldon, UK Rugby, UK 19.5 53 1.7 8 0.8 0.2 3 70.7 24 298.4 100 801.9 145 31.1 9 20.8 48 3.0 0.7 0.3 42 1.6 8 11308 15000 6.6 <1 0.1 <1

1

Jones H., Holland M., Buckley-Golder D. (2001). Environmental Health Impact Assessment - Rugby Cement, Tyre Burning Proposal. A report produced for Rugby Borough Council. 39p.

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ALTERNATIVE FUELS – Page 11/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-2 – ALTERNATIVE FUELS

•

“Carbon Neutral” or biomass content resulting from natural rubber content:

ƒ 26.7% - Italy 2007, avg of 9 analysis (CEN/TS 15440) ƒ Agreements with European Agencies (2007-09): 26% (AUS), 27% (RO, GER), 32%(CZ, PL) ƒ France: 13% for passenger tyres, 26% for truck tyres. Average value = 14.6% used, based on historic waste tyre stream of 88% passenger and 12% truck tyres from study (2007) for ADEM (French Environmental Ministry)

•

Impact of Tyres on Clinker Iron content

ƒ 25% tyre substitution will raise iron content of clinker by +0.5-0.7% •

Tyre weight of mixture of passenger & light truck tyre:

ƒ 8.0 kg (Range: 5 - 16 kg), Weigh test of car + light truck tyres by St. Constant ƒ 9.1 kg, Standard reference used in USA from “TNRCC report” General Comments Tyre Firing

• Tyre chips: objective of the injection point is the longest path in oxygen. Gas velocity, oxygen and T profile of most risers and calciner is highly segregated. A 3-5m acceleration zone of 38-45 m/s will arrest the terminal velocity of a 50x50mm chip, thus burning the majority of the chips in semisuspended circulation with the upwards rising gas stream becomes possible. At lower gas speed, the most chips will fall onto the riser slope and create high CO and build-ups. Higher velocity will carry chips to the cyclone and increase carbon in hot meal sample (build-up risk in cyclone!)

o

Size & quality - 50mm clean-cut (max 10mm protruding wire) tyre to prevents “bird-nests”. Chips of 70, 100-200, even 300mm tyre chips used but at significantly lower rates and elevated CO, build-up issues.

• Whole tyre: objective is to roll tyre into rotary kiln towards high BZ temperature, not to fall and burn on kiln slope which creates higher CO and related build-up issues o tyre chute should be aligned with axis of the kiln adjacent to meal pipe, o AS-PC and short L/D kilns will have lower max whole substitution rate than AT-PC or PH which have higher SHC, higher inlet O2, and longer BZ residence time o High substitution rates (25-30%) on PH kiln generally also create high tower outlet CO

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ALTERNATIVE FUELS – Page 12/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-2 – ALTERNATIVE FUELS

•

Tyre Substitution rates – Kiln process, whole vs. Chips (ref – Tyre Synthesis 2007) Type

%Tyres (usual) 13%

Plant

Country

TDF type

Injection point

KLWT WESTBURY MYKOLAIEV KGSW NORTHFLEET JOPPA ST CONSTANT KLDR TULSA ATLANTA Lepol LA MALLE HOGHIZ MALOGOSZCZ RETZNEI KSPH WHITEHALL KARSDORF TULA KPAT OCUMARE CIZKOVICE HARLEYVILLE KPAS KUJAWY BATANGAS ROBERTA Shreds or Chips PESCARA Lepol VDZ WOESSINGEN KANDA KPAS LE HAVRE MEKNES kiln 2

UK Ukrain UK USA Canada USA USA France Romania Poland Austria USA Germany Mexico Venezuela Czech R USA Poland Philippines USA

whole car tyres whole - small & medium whole whole whole whole, car & truck whole whole (car tyres only) whole/shreds whole whole (car & truck) whole (car & truck) whole (car & truck) whole (car & truck) whole whole (car & truck) whole (& chips in past) whole (car only) whole car whole ( car, truck)

Mid-kiln (gate at 40%) Mid-kiln (gate at 37%) Mid-kiln (38% position) Mid-kiln + MAFs Mid-kiln + MAF on K1 Mid-kiln (36% position) Mid-kiln (37% position) Lepol grate Kiln inlet Kiln inlet / riser Kiln inlet + MAFs Kiln inlet + MAFs Kiln inlet kiln inlet Kiln inlet / riser Kiln inlet Kiln inlet/calciner Kiln inlet Kiln inlet / riser kiln inlet

Italy France Germany Japan France Morocco

shreds (200 mm) shreds (70 - 100 mm) shreds (200 mm) shreds (300 mm) shreds (200 mm) shreds (50-300 mm) shreds (100-200 mm + SSW blend) chips (50 mm) shreds (50-100 mm) shreds (50-300 mm) shreds (50-300 mm) chips (40-50 mm + SSW chips (35-50 mm) chips (50-75 mm) chips (SSW blend) shreds shreds (50-300 mm) shreds shreds (80 x 80 mm) chips (20-30 mm)

Lepol grate Lepol grate Lepol grate Kiln inlet / riser Kiln inlet Kiln inlet / riser

8% 3% 19% <1% 5% 25%

Kiln inlet

18%

Riser Riser Riser / kiln inlet RSP, mixing chamber Vessel calciner Vessel calciner (2 pts) Gooseneck calciner Vessel calciner Vessel calciner RSP, mixing chamber Kiln inlet Calciner Off-line calciner

14% <1% 16% 8 - 10% 7% 30% 12% 12% 2% 12% 3-7% 8% 8 - 9%

ARCOS Quarry KPAT HOPE LA COURONNE BOUSKOURA K2 BOUSKOURA K1 CANTAGALO CAULDON DUNBAR MATOZINHOS KPAS MEDGIDIA MEKNES kiln 1 OKKE LANGKAWI SPLC

6.2

Brazil UK France Morocco Morocco Brazil UK UK Brazil Romania Morocco S. Korea Malaysia France

12% 17% 13% 12% 7% 5% 20% 24% 25% 6% 10% 4 - 8% 16% 8% 4% 2% 3-4%

Short-term %max 20% 18% (test) 20% 20% 20% 28% 15% 20% 26% 30% 6% 9 - 10% 19% 12% 7% 5%

20% 7% 25% 5%

Total %AF 6.7

16.5 27.2 12.4 37.8 6.0 30.8 60.0 22.4

7.1 56.1 18.9 1.6 15.0 3.5 33.8 42.6 38.4 10.2 29.2

30% 32.7 20% 5% 16% 20% 25% 55% 28% 25% 5% 15% 8% 16% 15%

13.9 8.3 4.2 21.7 39.8 33.1 52.6 5.3 11.5 4.3

Solid Shredded Waste

• SSW by CKHC classification includes all non-hazardous shredded industrial, commercial or municipal solid waste o There is no accepted industry definition for common terms like SRF, RDF, ASB, DSB, etc

o o

o

See SSW Synthesis for description of different solid waste sources for SSW Characteristics (Cv, chlorine, ash, moisture, etc) are strongly dependent on the origin and pre-treatment. Similar combustion behaviour with other solid wastes - impregnated solid residues, biomass, etc. but can require different handling solutions. SSW has potential for carbon-neutral biomass (CO2) credits due to cellulose or natural rubber content, amount depends on origin

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ALTERNATIVE FUELS – Page 13/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-2 – ALTERNATIVE FUELS

•

Typical SSW Mixture Composition (Ultimate Analysis)

ƒ Mixture of pre-treated commercial & industrial (source separated) non-hazardous, solid wastes: ƒ Ash content depends on waste source and pre-treatment, i.e. "cleanliness of material". RDF (refuse derived fuel) will contain "inert contamination" (stones, glass, metal, etc) which will be part of the %ash, “Clean” = 10-20%, "Dirty" = 20-30% ash (moisture free)

ƒ Content of natural wastes (e.g. wood vs. plastics) impacts O2, Cv, chlorine. ƒ PVC is the most common source of Cl in SSW. Often concentrated in high density 3D, this can be reduced with air separation installed at pre-treatment facility

ƒ Moisture content has greatest impact on combustion gas volumes. Normal range: 10-25%H2O, 15%H2O is a typical value. Raw RDF from municipal waste (MSW) can exceed 50%H2O

•

Typical SSW (Ultimate Analysis) TYPICAL EXAMPLE

RANGE

C [%dry]

60.0

45-65

H [%dry]

10.7

4-12

S [%dry]

0.3

<2

O [%dry]

11.0

8-15

N [%dry]

0.2

<2

Cl [%dry]

0.8

0.5-3.0

Ash [%dry]

17.0

10-40

23 000

16 000-28 000

10

5-50

20 500

10 000-26 000

LHV dry [kJ/kg] Moisture [%] LHVas fired [kJ/kg]

•

Estimated RDF Ash Analysis for pre-treated municipal solid waste (MSW)

o o

SiO2: 40-60%, Al2O3: 10-20% (partly metallic), CaO: 20-30%, Fe2O3: 5-10% (partly metallic), Na2Oeq: 5-10% MgO: <3%, P2O5, TiO2, Mn2O3: each <1%.

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ALTERNATIVE FUELS – Page 14/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-2 – ALTERNATIVE FUELS

•

“ASB, Fluff, SRF” Analysis: Monthly average (2006), Retznei (Austria)

Moisture HV HV Chlorine As Be Cd Co Cr Cu Hg Mn Ni Pb Sb Sn Zn Tl V

% kJ/kg kJ/kg dry % mg/kg dry mg/kg dry mg/kg dry mg/kg dry mg/kg dry mg/kg dry mg/kg dry mg/kg dry mg/kg dry mg/kg dry mg/kg dry mg/kg dry mg/kg dry mg/kg dry mg/kg dry

Spec. 80th percentile

Spec (Max)

10

15

15 15 150 300 0.6 200 100 150 20 30

25 20 300 500 1 200 500 30 70

1.5 30

3 70

Annual Avg (2006) 10.9 22 491 25 238 1.11 1.4 < 0,1 5.8 4.2 96 747 0.11 106 26 183 68 26.3 413 0.05 5.1

Minimum (Month avg) 6.9 20 147 24 331 0.78 0.8 < 0,1 1.4 1.8 37 144 0.04 55 13 98 14 6.2 141 0.05 2.7

Maximum (Month avg) 17.0 24 120 26 519 1.58 2.6 < 0,1 14 7.5 157 1260 0.38 131 48 400 140 111 810 0.05 7.5

• Solid Shredded Waste Heavy Metal Regulatory Limits (Simplified) 1

Element [mg/kg]

* with 25 [MJ/kg]

Austria (Positveliste) Germany Plastics waste timber RAL - Gütegemeinschaft (Exception 3) (Exception 4) weekly monthly weekly monthly 80th avg. avg. avg. avg. Median Percentile

As Sb Be Pb Cd Cr Co Cu Ni Hg Tl V Zn Sn Cl PCB Te Se Mn Ba Ag

15 5 5 200 2 100 20 100 100 0.5 3 100 400 10 1 [%] 50 [ppm]

15 1 20 (800 ) ** 1000 500 50 27 500 300 100 500 200 4 2 10 * 0.1 [%] 70 2.5 [%] 2 [%] **

Waste Fuel

Hg+ Cd+ Tl As+Ni+Co+ Se+Te+ Cr+ Pb+Sb+Sn+V

1500 20 150

2

**

15 5 13 20 25 60 ** 0.5 2 1 2 1 200 ** 70 190 800 15 4 9 1 2 1 2 120 250 40 125 70 ** 6 12 1 2 ** 400 120 350 1 2 1 2 50 160 25 80 ** 1 0.6 1.2 ** 1 2 ** 10 25 0.4 [%] 20 30 70 ** 3 5 3 5 1 2 1 2 50 250 100 500

Swiss

France

Buwal with 25 [MJ/kg] 15 5 5 200 2 100 20 100 100 0.5 3 100 400 10

10

UK Philippines Draft SFP 2008 regulation Guidelines

50 300

500 10000

200 +Tl < 20 200 100 300

5000 1000 120

10

5000 10000 50

100 200 1 [%] 50

10000 yes

5 100 200 5

5.5

39

19

5.6

12.2

5.5

100

550

2085

1145

827

1150

555

2 500

30

1

*, ** - exceptions apply. 1) , 2): German limit depend on waste origin - H.M. limits are for Cv > 16 MJ/kg for municipal waste and > 20 MJ/kg for product specific waste. For lower Cv limits are reduced linearly

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ALTERNATIVE FUELS – Page 15/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-2 – ALTERNATIVE FUELS

• SSW Performance Bench Marking - (ETC 2008, SSW Synthesis 2005) Reference - ETC Benchmarking 2008 Plant

Process

KAR 4 KAR 3

KSPH KSPH KPAS KSPH KSPH KPAS

MDF REI MAL CIZ

SSW size

2D (chiefly) 2d+3d<10mm <25-30mm <25mm

KUJ KPAS <25-30mm KPAS <20 mm WOS Reference - SSW Synthesis (2005) Mannersdorf Whitehall Cantagalo

KSPH KPAS

Tagawa

KPAS

Le Havre Kamloops Harleyville Richmond Kanda Pescara Kumagaya (Taiheiyo) Montalieu (Vicat) Antoing (Italcementi)

KSPH KLDR KPAS KPAS KSPH KGSD

27.2 21.7 26.1 25.0 17.1 16.7

%AF total 69.6 66.0 30.4 71.5 41.2 63.8

LHV (GJ/t) Moy Min Max 20.1 14.7 27.2 20.1 14.7 27.2 20.7 25.6 17.7 21.7 18.1 24.4 19.9 15.0 23.0 20.7 11.9 37.2

16.0

21.7

19.5

10.8

26.3

19.0 15.8 22.0 7.0

9%

39%

23.5

17/ 25% 16/ 25%

23% 20%

38 15-30

9 / 20%

11.5%

29

7/ 10% 6.5% 7% 5% 5% 3/ 5%

26.5% 6.5% 15% 5% 13% 31%

26.7 29.2 30.9 N/A 31 24.3

Injection point(s)

%SSW 2008

Main burner Main burner Precal Main burner Main burner Main burner Precal - RSP (pneumatic) Main burner

Moy 11.2 11.2 11.1 7.7 13.4 12.8

%H2O Min Max 2.7 24.4 2.7 24.4 5.0 15.0 2.4 13.9 8.8 21.1 1.1 40.4

Moy 0.7 0.7 1.0 1.2 0.8 1.0

%Cl Min Max 0.10 2.1 0.10 2.1 0.50 3.1 0.53 1.0 0.01 3.1

9.6 30.5 13.4 1.2 37.8 1.2 0.09 5.0 1.4 15.5 0.7 0.45 1.2

Avg/ Max

2-D : 30 mm 3-D : 15 mm Main burner flakes < 18-20 mm Main burner < 75 mm Calciner 2-D : 30 mm Calciner & riser 3-D : 15 mm duct 75-250 mm / 50100 mm Hearth area < 38 mm Main burner 2-D, 50 mm Calciner N/A RSP Calciner variable Riser duct 20 mm Main burner

KPAS

100 mm

Calciner

13%

N/A

N/A

KPAS

60 mm

10-15%

56%

N/A

KPAS

N/A

Calciner RSP calciner (2 points)

N/A

60%

32.5

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ALTERNATIVE FUELS – Page 16/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-2 – ALTERNATIVE FUELS

6.3

Biomass

ƒ The Cv of wood varies little with tree species; for dry wood (18-21 kJ/kg). Average green wood moisture is 50-60%. Once harvested, moisture drops to fibre saturation point – from weeks to months depending on climate. The fibre saturation point is 20-40%, mean = 30% moisture. Drying of wood chips is relatively independent of air temperature or relative humidity. Chips (and other biomass) stored in large piles can be dried to fibre saturation by fermentation - which can raise internal pile temperature to 90C. 1 (but can lead to smoldering fires),

ƒ HHV 2 dry basis (in kJ/g) = 0.3491C + 1.1783H - 0.1034O - 0.0211A + 0.1005S - 0.0151N • Biomass and some synthetic Fuels 3 % FC

%Volatiles

WOOD Douglas Fir 17.7 Western Hemlock 15.2 Mango Wood 11.4 BARK Douglas Fir bark 25.8 ENERGY CROPS Eucalyptus Camaldulensis 17.8 Poplar 16.4 Sudan Grass 18.6 PROCESSED BIOMASS Plywood 15.8 AGRICULTURAL Corncobs 18.5 Wheat Straw 19.8 Cotton Stalk 22.4 Sugarcane Bagasse 15.0 Rice Hulls 15.8 AQUATIC BIOMASS Kelp (Brown, Giant) AVERAGE LIQUID FUELS Methanol, CH3OH 0.0 Ethanol, C2H5OH 0.0 PYROLYSIS OILS LBL Wood Oil BOM wood oil Coke-oven tar Low Temp Tar SOLID FUELS Peat, S-H3 26.9 Charcoal 89.3 Oak char (565C) 55.6 Casuarina Char (950C) 71.5 Eucalyptus char (950C) 70.3 ORGANIC CHEMICALS Cellulose; C6H10O5 Lignin (Softwood) PULP & PAPER (Weyerhaeuser) Pulper Tails 8.8 OCC Reject 9.3 Paper Sludge 19.1

%Ash

%C

%H

%O

%N

%S

HHV dry (kJ/g)

81.5 84.8 85.6

0.8 2.2 3.0

52.3 50.4 46.2

6.3 5.8 6.1

40.5 41.1 44.4

0.10 0.10 0.28

0.00 0.10

21.1 20.1 19.2

73

1.2

56.2

5.9

36.7

0.00

0.00

22.1

81.4 82.3 72.8

0.8 1.3 8.7

49.0 48.5 44.6

5.9 5.9 5.4

44.0 43.7 39.2

0.30 0.47 1.21

0.01 0.01 0.01

19.4 19.4 17.4

82.1

2.1

48.1

5.9

42.5

1.45

0.00

19.0

80.1 71.3 70.9 73.8 63.6

1.4 8.9 6.7 11.3 20.6

46.6 43.2 43.6 44.8 38.3

5.9 5.0 5.8 5.4 4.4

45.5 39.4 43.9 39.6 35.5

0.47 0.61 0.00 0.38 0.83

0.01 0.11 0.00 0.01 0.06

18.8 17.5 18.3 17.3 14.9

57.9

42.1

27.8 47.9

3.8 5.7

23.7 41.0

4.63 0.52

1.05 0.05

10.8 19.1

0.0 0.0

37.5 52.2

12.5 13.0

50.0 34.8

0.00 0.00

0.00 0.00

22.7 30.2

0.8 0.7 0.3

72.3 82.0 91.8 83

8.6 8.8 5.5 8.2

17.6 9.2 0.8 7.4

0.20 0.60 0.90 0.60

0.01 0.00 0.80 0.80

33.7 36.8 38.2 38.8

3.0 1.0 17.3 13.2 10.5

54.8 92.0 64.6 77.5 76.1

5.4 2.5 2.1 0.9 1.3

35.8 3.0 15.5 5.6 11.1

0.89 0.53 0.40 2.67 1.02

0.11 1.00 0.10 0.00 0.00

22.0 34.4 23.1 27.1 27.6

44.4 63.8

6.2 6.3

49.4 29.9

64.9 69.1 31.1

10.3 9.4 7.0

20.4 16.5 48.7

0.33 0.42 0.29

0.06 0.14 0.1

32.9 33.3 12.5

70.1 93.9 27.1 15.2 19.2

87.3 85.3 68.1

3.9 5.4 12.9

1

Opportunity study, Ligneous biomass in Lafarge Nigeria, ONF International

2

Channiwala 1992 Indian Institute of technology. Average error for biomass compared to table was +/- 1.5%.

3

S. Gaur and T. Reed, Marcel Dekker, 1998

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ALTERNATIVE FUELS – Page 17/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-2 – ALTERNATIVE FUELS

7.

Solid AF Main Burner Firing

• Also see SSW Performance Benchmark table • Experience indicates substitution rate limitation for main burner solid AF at the main burner is localized reducing conditions (impact on clinker microscopy) from high density 3D particles (e.g. foams or porous particles not issue). Also see benchmark table o max 30% solid AF (SSW+MBM+ISF+biomass) o max 25% SSW o max 20-25% SSW with high 3D content, higher end may require <6mm 3D

•

SSW Injection Main Burner – ETC Conclusions (2010)

ƒ High impulse burner; aligned on axis of kiln; 0-15 cm into kiln (cold) ƒ Lafarge Burner: Is =2.2, Sw =0.15, 70% axial, 30% swirl (volume) ƒ Unitherm Burner: Pressure MAS – 200 mBar, Swirl 4-7 ƒ Injection velocity: 30-40 m/s ƒ Injection in the centre rather than above Recommended AF Injection Point for Main Burner (Ref: TA Fuel Flexibility) Solvents

Used Oil SSW

Impregnated Solids Residues Biomass Sewage Sludge

1st choice: 2 2nd choice: 3 3rd choice: 4 4th choice: 5 1st choice: 3 1st choice: 1, 2, 3 2nd choice: 6 3nd choice 5 1st choice: 1, 2, 3 2nd choice: 6 3nd choice 5 1st choice: 1, 2, 3 2nd choice: 6 1st choice: 1, 2, 3

- The 2nd choice is from experiences, at low momentum the secondary air can push the flame from light fuels upwards to help ignite the main flame and tighten the plume. - The 4th choice is for high LHV solvents - To avoid dripping into other channels & coking - Anywhere in the center is OK - Use of easy-to-ignite fuels such as used oil can help %rate by sustaining flame stability. - Anywhere in the center is OK

- Anywhere in the center is OK - Anywhere in the center is OK

ƒ Location 5 is of the same side as the kiln load. ƒ Solvents: If high suspended solids in LWF, the driver could be particulates (treat as a solid fuel) or its properties as volatile liquid with a tendency to lifted by the SA. Momentum may be a deciding factor. If unclear do plant trials and observe flame. Conveying line 1.8-2.2 kg SSW/kg air and 22-30 m/s. A mix of 2D and 3D can ease pneumatic conveying. SSW injection velocity: 35-40 m/s, Impregnated residues: 26-33 m/s, Biomass: 22-29 m/s

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ALTERNATIVE FUELS – Page 18/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-2 – ALTERNATIVE FUELS

8.

Reference AF Documents

• RR Guidelines 1 • Waste Model Shops (Liquid, Whole tyres, SSW backend, SSW main, etc) • RR Synthesis – Tyres, SSW, ARM, Used Oil • Technical Agenda Studies o TA Fuel Flexibility o TA Build-up o TA Precalciner o TA Bypass

1 The RR Guidelines were approved by all TC Directors. However, they are an internal document and not yet approved for outside publication.

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ALTERNATIVE FUELS – Page 19/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 2-2 – ALTERNATIVE FUELS

My notes:

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ALTERNATIVE FUELS – Page 20/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-1 – KILN HEAT & MASS BALANCE

3-1. Kiln Heat & Mass Balance

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KILN HEAT & MASS BALANCE – Page 1/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-1 – KILN HEAT & MASS BALANCE

Table of Contents 1.

Kiln / Preheater Exit Gas Calculation ........................................................3 1.1

Calculation of neutral waste gas out of fuel elemental analysis (as fired basis) .............................................................................................................. 3

1.2

Calculation of CO2 and H2O from material and water spraying .................... 3

1.3

Calculation of Excess Air and Kiln Exit Gas ................................................... 4

1.4

Typical exit gas for different kiln types............................................................ 4

2.

Pyroprocessing Reactions by Zone ..........................................................5

3.

Cooler Efficiency .........................................................................................6

4.

5.

3.1

Cooler Parameters ......................................................................................... 6

3.2

Recuperation Efficiency (ρ): ........................................................................... 8

3.3

Recovery Factor (k) ........................................................................................ 8

Wall Losses .................................................................................................9 4.1

General Formula............................................................................................. 9

4.2

Radiation Losses ............................................................................................ 9

4.3

Convection Losses ....................................................................................... 11

Kiln Audit Basics.......................................................................................11 5.1

Defining the Balance Envelope .................................................................... 11

5.2

Measurements .............................................................................................. 13

6.

Kiln Heat Balance Example: .....................................................................15

7.

Kiln Audit Results – Preheater / Calciner Kilns......................................16

8.

Kiln Simulated Optimum Parameters ......................................................17

9.

References .................................................................................................19

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KILN HEAT & MASS BALANCE – Page 2/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-1 – KILN HEAT & MASS BALANCE

1.

Kiln / Preheater Exit Gas Calculation

1.1 Calculation of neutral waste gas out of fuel elemental analysis (as fired basis) Neutral Combustion Air (NCA):

%H %S %O ⎞ 22.414 Nm 3 ⎛ %C =⎜ + + − ⎟* kgfuel ⎝ 12.001 4.032 32.064 32 ⎠ %OXYair Neutral Combustion (Waste) Gas:

% H % H 2O %S % N ⎞ 22.414 %OXYair ⎞ Nm 3 ⎛ %C =⎜ + + + + + (1 − ⎟* ⎟ * N .C. A 100 ⎠ kgfuel ⎝ 12.001 2.016 18.015 32.064 28.01 ⎠ 100 Definition: o Neutral Combustion (Waste) Gas: Combustion gas of a fuel or fuel mix under stoechiometric condition (0% Oxygen in the waste gas). o Neutral Combustion Air: Air required for complete stoechiometric combustion of the fuel. Sulphur is typically not remaining as SO2 in the waste gas as calculated in the formula above. All or most of it is trapped in the kiln system and finally present in clinker as SO3. For final exit gas calculation this effect is considered in the division heat balance tool.

1.2

Calculation of CO2 and H2O from material and water spraying

CO2 from Calcination

H2O from Feed or Slurry Moisture

•

0.786 * CaO + 1.092 * MgO kg / kgdryRM 100 0.786 * CaO + 1.092 * MgO 100 = * kg / kgkk 100 100 − LOI

•

•

Typical value:

•

CO 2 =

0.53 kg/kgkk

SM kg / kgdryRM 100 − SM SM 100 * kg / kgkk 100 − SM 100 − LOI H 2O =

0.35 kg/kg RM

Typical value for wet lines: 0.865 kg/kgkk 1.08 Nm³/kg kk

0.27 Nm3/kgkk An exact calculation of the material related CO2 and H2O in exit gas requires a mass balance, crystal water analysis, CO2 analysis of kiln feed and dust(s), especially when using already decarbonated raw materials (fly ash, slag...). This calculation is done in the division heat balance tool.

H2O from Water Spray •

WS liters/kgkk = WS kg/kgkk

In calciner and preheater kilns only a part of CO2 is present in the kiln exit; most of it is released in the calciner / preheater.

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KILN HEAT & MASS BALANCE – Page 3/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-1 – KILN HEAT & MASS BALANCE

1.3

Calculation of Excess Air and Kiln Exit Gas

Excess Air

EA =

•

KEGN * OXYki ln OXYair − OXYki ln

KEGN: Neutral Kiln Exit Gas including material CO2 and H2O [Nm³/kg] OXYkiln: Oxygen reading kiln exit, wet OXYair: Oxygen content in air Definition: o

Excess Air Kiln: Amount of air in addition to neutral combustion air kiln to achieve the Oxygen at kiln inlet (for benchmark the defined analyzer position is inside kiln = kiln inlet seal false air excluded!).

o

Total Combustion Air Kiln: Neutral Combustion Air Kiln + Excess Air Kiln.

o

Excess Air Kiln Line (preheater / calciner kilns): Amount of air in addition to neutral combustion air kiln line to achieve the Oxygen at preheater exit.

o

Total Combustion Air Kiln Line (preheater / calciner kilns): Neutral Combustion Air Kiln Line + Excess Air Kiln Line.

Kiln and Preheater exit (waste) gas is the sum of neutral combustion gas from fuel, CO2 and H2O from raw material, H2O out of water spraying and the excess air. Further impacts like a gas bypass, CO in exit gas and combustibles in raw material are considered in the division heat balance tool. In case of preheater / calciner kilns the calculation is done separately for kiln exit gas and preheater exit gas.

1.4

Typical exit gas for different kiln types

KILN TYPE

Nm³/kg

%CO2

%H2O

%N2

%O2

Wet – kiln exit

3.20

16.9

35.4

45.3

2.3

Long Dry – kiln exit

1.67

27.9

5.6

63.1

3.3

Lepol – Lepol exit

2.33

19.2

16.9

57.3

6.7

4 stage preheater – PH exit

1.54

28.8

5.9

61.6

3.8

4 stage calciner – PH exit

1.47

30.2

6.1

60.8

2.8

5 stage calciner – PH exit

1.43

30.6

6.2

60.4

2.8

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KILN HEAT & MASS BALANCE – Page 4/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-1 – KILN HEAT & MASS BALANCE

Kiln exit gas for wet and long dry is considered inside kiln, without false air at settling chamber and without water injection. Values are with 100% petcoke firing under optimized conditions (see chapter kiln simulated optimum parameters)..

2.

Pyroprocessing Reactions by Zone

Example Preheater Kiln Between 100° and 400°C

•

H2O (l) → H2O (g), ΔH = - 2488 kJ/kg

Between 400ºC and 800ºC

•

Clay loses its crystal water (dehydroxylation):

2 SiO2. Al 2 O3 . 2 H 2 O → 2SiO2 . Al 2 O3 + 2 H 2 O( g ) , ΔH ~ - 5600 kJ/kg crystal water Required evaporation energy varies with type of clay.

•

Decomposition of Magnesium carbonates: MgCO3 → MgO + CO2 (g), ΔH = - 2932 kJ/kg MgO

•

Vaporization and oxidation of organic Carbon and Sulfides:

4 FeS 2 + 11 O2 → 2 Fe2 O3 + 8SO2 , ΔH = + 13120 kJ/kg S C + O2 → CO2 , ΔH = + 33830 kJ/kg C (Fly ash Carbon has a higher temperature window compared to natural TOC-Carbon in clay or marl)

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KILN HEAT & MASS BALANCE – Page 5/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-1 – KILN HEAT & MASS BALANCE

Between 750°C and 950ºC

•

Decomposition of Calcium carbonates:

CaCO3 → CaO + CO2 , ΔH = - 3175 kJ/kg CaO Between 800°C and 1250ºC

•

Free lime reacts in solid phase with oxides to intermediate phases like:

2CaO + SiO2 → 2CaO . SiO 2 , 2CaO + Al 2 O3 → 2CaO . Al 2 O3 , 2CaO + Fe 2 O3 → 2CaO . Fe 2 O3 And finally Belite (C2S), C3A and C4AF start to form. The reaction is exothermic. Between 1250°C and 1450ºC

•

C 3 A and C4 AF liquefy and constitute the flux. Belite ( C 2 S ) combines with free CaO to form Alite ( C 3 S ) in the presence of flux, forming nodules.

The reaction is exothermic. Alite and Belite are not pure, they contain impurities (Al2O3, Fe2O3, MgO, SO3, Alkali,…). Rietveld or microscopy results show higher Alite compared to Bogue C3S calculation. Evaporation of volatiles overlaps the exothermic reaction in the sintering zone and transfer heat to colder areas. The final exothermic reaction of the clinker phases is estimated on clinker Bogue results: 3CaO + SiO2

Alite (C3S) ΔH = + 494 kJ/kg C3S

2CaO + SiO2

Belite (C2S) ΔH = + 699 kJ/kg C2S

3CaO + Al2O2

Aluminate (C3A) ΔH = - 75 kJ/kg C3A

4CaO + Al2O2 + Fe2O3

Ferrite (C4AF) ΔH = + 67 kJ/kg C4AF

Alkalisulphates need to be considered as well: K2O + SO3

K2SO4

ΔH = + 9690 kJ/kg K2SO4

3.

Cooler Efficiency

3.1

Cooler Parameters

•

Basic operating principles: Maintain a constant air to clinker ratio Maintain a constant bed depth Remove all excess cooling (vent) air

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KILN HEAT & MASS BALANCE – Page 6/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-1 – KILN HEAT & MASS BALANCE

•

Design Criteria: Grate Loading < 45 tpd/m² Total specific cooling air > 2.1 Nm³/kg cl Target: clinker temperature 70°C + ambient ; k- factor > 1.6

•

Blowing Density: Expressed in Nm³/m²/s. Calculate the blowing density for every compartment using the effective area (covered by clinker) and the cooling air blown in the compartment. Take care to consider the grate area covered by horse shoe. Rule of thumb for blowing density of the static grate or first chamber: 1.6 – 1.8 Nm³/m²/s for conventional grate cooler and old Fuller cooler 1.5 for IKN fixed inlet (some plants will need up to 2) 1.3-1,4 for FLS ABC inlet Higher airflow might be required to avoid static areas of clinker that could result in snowman formation. The objective of a fixed inlet is to ensure a good distribution of clinker on the moving grate. The blowing density of the following chambers should show a constant decrease. Use the Lafarge cooling air distribution spread sheet for a first assessment.

•

Cooling Air: Expressed in Nm³/kg cl. While optimizing the air in the recuperation zone often requires an increase at the first fans, the total cooling air should be minimized to reduce power cost. Decide on a clinker target temperature required for cement quality but do not go below this temperature. An optimized cooler can achieve low clinker temperature with low total cooling air. Typical figures: 1.8 to 2.2 Nm³/kg cl, old grate coolers without fixed inlet up to 2.4 Nm³/kg cl.

•

Clinker Bed Height Maximize the bed height to increase the heat exchange. Typical limit is the fan’ maximum static pressure and the need to keep reserves to act in case of a kiln push. New conventional coolers can maintain a bed of 500 – 700 mm. Track the bed height by measuring or set marks to observe from inspection windows.

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KILN HEAT & MASS BALANCE – Page 7/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-1 – KILN HEAT & MASS BALANCE

3.2 •

Recuperation Efficiency (ρ): ρ=

heat gained by recovered gases hsa + hta = m + mta total usable heat input hck ,in + hca sa mca

Where: hsa is the enthalpy of secondary air in kJ/kg ck, including enthalpy of clinker dust in secondary air. hta is the enthalpy of tertiary air in kJ/kg ck, including enthalpy of dust in tertiary air. hca is the enthalpy of cooling air in kJ/kg ck hck in is the enthalpy of the hot clinker from the kiln in kJ/kg ck, increased in mass flow due to dust return. msa=mass of secundary air in kg/h mta=mass of tertiary air in kg/h mca=mass of cooling air in kg/h

The calculation in the division heat balance tool is considering the exact enthalpy of the cooling air in the recuperation zone, which is typically higher compared to the average enthalpy of the cooling air.

•

3.3 •

This efficiency depends highly on the quantity of secondary and tertiary air. It is higher for wet kilns (∼85%) than for dry kilns (∼70%).

Recovery Factor (k) ln (1 − ρ ) k= m sa + mta k < 0.9

⇒ bad cooler

0.9 < k < 1.1

⇒ poor cooler

1.1 < k < 1.3

⇒ mediocre cooler

1.3 < k < 1.5

⇒ good cooler

k > 1.5

⇒ excellent cooler

The k-factor is the main indicator for cooler performance benchmark. The k-factor is independent from the amount of secondary and tertiary air and therefore shows cooler performance independent from the kiln system or fuel used.

© Copyright 2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

KILN HEAT & MASS BALANCE – Page 8/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-1 – KILN HEAT & MASS BALANCE

Cooling Efficiency

•

η=

heat lost by clinker hck,in - hck,out = heat input in clinker hck,in

Cooler Loss •

Cooler loss = all heat not recovered by combustion air. Cooler loss = heat content of clinker leaving cooler ( hck ,out ) + heat content of vent air including dust + heat content of any mid air extraction including dust + cooler wall losses

4. 4.1

Wall Losses General Formula

The total heat loss from a surface is the sum of both the radiation and convection losses QTotal = Qradiation + Qconvection It is recommended to use the Division calculaltion tool to calculate Wall Losses, it can be found on the Cement Portal.

4.2

Radiation Losses

Radiation losses are given by the following equation: Qradiation= α x x σ x A x ( Tshell4 – Tsurroundings4) Qradiation is radiation loss in W α is the view factor, can be assumed =1 if the shell is a long distance from surrounding surfaces

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KILN HEAT & MASS BALANCE – Page 9/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-1 – KILN HEAT & MASS BALANCE

is the emissivity of the surface σ is the Stefan Boltzmann Constant 5.6703x10-8 (W/m2.K4) A is the surface area in (m2) Tshell is the shell temperature in (Kelvin) Tsurroundings can be assumed as the ambient temperature when the surroundings are a long distance from the shell (Kelvin) A surface in close proximity to the shell can reflect the thermal radiation back to the shell and reduce the heat transferred. This will depend upon the size, shape, emissivity and temperature of the surface. The size, shape and distance of the surface from the shell will affect the view factor. The view factor is the proportion of the surface that can be “seen” by the shell. Calculation of the view factor becomes quite complex, even for relatively simple shapes, hence assumptions have to be made to simplify the calculation (done in the division tool). The emissivity is a property of the material and its surface condition (see below). Emissivity e: Material

Emissivity ∈

Bricks

0.8

Steel

0.95

Oxidized steel

∈ =0.996-2.88*10-4.(tp-100) ∈ =0.96-5.2*10-4.(tp-100) ∈ =0.81-6.08*10-4.(tp-200)

Dusty kiln shell Silica bricks

Other data

Tp

∈

tp

∈

Iron oxide

500C

0.78

Steel oxidised

40C

0.94

Zinc galvanized sheet bright

28C

0.23

Steel oxidised

370C

0.97

Iron polished

425C

0.144

Steel polished

770C

0.52

Steel dense shiny oxide layer

25C

0.82

Steel pipe

200

0.8

It is important to take care to use the correct value since an incorrect emissivity value will create a significant error in the “measured temperature” and hence the calculated heat loss, see example. Emissivity can be checked on static surfaces by first measuring the temperature with a contact pyrometer and then pointing the infra-red pyrometer at the same point and adjusting the emissivity until the temperature reads the same as that measured by the contact thermometer.

Example: Measurement Error with Incorrect Emissivity Read temperature=65C, emissivity chosen: 1 instead of actual: 0.4 ambient temp 20°C True temperature= t = ( 273 + 65 ).4 1 / 0.4 = 425 K = 152C Loss calculated with read temperature = 322 W/m2 Loss with true temperature = 573 W/m2

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KILN HEAT & MASS BALANCE – Page 10/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-1 – KILN HEAT & MASS BALANCE

4.3

Convection Losses The individual formula for convection losses are too numerous depending on the flow type to be presented here. The general formula is : Qconvection= h x A x ( Tshell – Tambient) Tshell is the shell temperature (°C) Tambient is the ambient temperature (°C) A is the surface area (m2) h is the coefficient of heat transfer (W/m2.°C)

The convection losses are influenced by: o

The movement of air around the surfaces. The speed of the wind, kiln speed, blowing fan change the convection losses from natural to forced convection and from laminar to turbulent movement.

o

The orientation and the form of the surface: ducts, vertical or horizontal area… e

With h = hnat * (1+0.57 v) hnat is the natural convection coefficient which depend of the surface orientation, and the type of flow : laminar or turbulent For calculating hnat you need a characteristic dimension of the surface considered: for Duct = the Diameter, Vertical plane shell = the height, Horizontal plane shell = the length For example for a horizontal pipe and laminar flow: hnat =1.18* (( Tshell – Tambient)/D)0.25 v e

5.

is the speed of the air surrounding the surface (including wind, kiln speed, fans…) (m/s) is the exponent reflecting the impact of wind (varying from 0.5 to 0.8)

Kiln Audit Basics 5.1 Defining the Balance Envelope

•

A kiln heat balance is a powerful tool to evaluate the actual performance of the burning line as well as to define improvement actions. To get reliable data a kiln audit is required.

•

In a kiln audit a Mass and Heat Balance is carried out for at least 24 hours reasonable stable operation.

Σ heatin = Σ heatout Σ massin = Σ massout © Copyright 2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

KILN HEAT & MASS BALANCE – Page 11/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-1 – KILN HEAT & MASS BALANCE

•

A clear definition of the balance border around the pyro line is essential, all mass and energy flows passing this envelope need to be considered. A typical balance border and Heat In - Output Table of a calciner line is shown below:

gas analysor

A new CY07

314TC0 5

CY09

CY11

CY21

CY19

CY23

ID fan

CY13

CY25

CA3 3

CY27

CY31

oil burner

oil burner gas burner

gas burner

gas analysor

A

M

• Heat Inputs o

Kiln feed (sensible + latent)

o

Fuel main burner (sensible + latent)

o

Fuel calciner (sensible + latent)

o

Primary air and transport air main burner

o

Primary air and transport air calciner

o

Cooling air

o

False air

o

Exothermic Heat of clinkerization

• Heat Outputs o

Clinker

o

Preheater exit gas

o

Preheater exit dust

o

Cooler exhaust gas and dust

o

Endothermic Heat of clinkerization including decarbonatization

o

Heat of Water vaporization

o

Wall losses

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KILN HEAT & MASS BALANCE – Page 12/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-1 – KILN HEAT & MASS BALANCE

•

5.2

Additional to the over all heat balance of the pyro line a sub balance is carried out for the cooler and other areas of interest (conditioning tower, bypass,…).

Measurements

•

A 24 hour truck weighing is recommended for clinker.

•

To determine the preheater exit dust, truck weighing of the kiln filter dust is recommended. The raw mill needs to be stopped one hour before and during the weighing. Coal mill should be stopped in parallel or the amount of preheater exit gas and dust towards coal mill needs to be estimated. Any dust source (example gas conditioning tower) should be covered by truck weighing.

•

Further truck weighing is recommended for fuel if dosing is not reliable or cannot be calibrated properly.

•

The table below shows typical recommended process measurements and their frequency: MATERIAL / LOCATION

ANALYZE

FREQUENCY

COMMENTS

Ambient

p absolute ; T ; relative humidity

3 / day

Kiln Feed

T

2 / day

Kiln Feed Airlift

flow ; T ; p

1 / audit

Optional blower data

Preheater Gas

flow ; T ; p ; O2 ; CO ; NO ; CO2 ; SO2

2-3 / day

Parallel stack flow + O2 measurement recommended ; Dust content if no truck weighing possible

Preheater Radiation

Surface T ; wind speed ; ambient T

1 / audit

Follow how to measure wall losses

Preheater stages

T ; p ; O2 ; CO

1 / audit

Every stage exit

Primary air back end / calciner

Flow ; T ; p

1 / day

Transport air end / calciner

back

Flow ; T ; p

1 / day

Optional blower data

Cooling air Preheater

Flow ; T ; p

1 / day

Example SNCR nozzles,…

Calciner

T ; p ; gas

1 / audit

Mapping or spot at main areas

Tertiary Air

T ; p ; radiation

3 / day

T and p at both ends

Calciner Exit Gas

T ; p ; O2 ; CO ; NO ; CO2

3 / day

Kiln Exit Gas

T ; p ; O2 ; CO ; NO ; CO2

3 / day

Use water cooled lance for gas analyze

Kiln Radiation

Surface T ; wind speed ; ambient T

1 / audit

Mark operating shell cooling fans – use for crosschecking Scanner data

Hot Clinker Temperature

T

5 / day

Calorimeter

Primary burner

Flow ; T ; p

2 / day

Exhaust

Airs

main

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KILN HEAT & MASS BALANCE – Page 13/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-1 – KILN HEAT & MASS BALANCE

Transport burner

air

main

Flow ; T ; p

1 / day

Optional blower data

Cooling Air Kiln Hood

Flow ; T ; p

1 / day

Camera,…

Cooler fans

Flow ; T before and after fan ; p before and after fan

3 / day

Cross check with measurement (IP21)

Cooler Exhaust Gas

Flow ; T after cooler and on flow measurement point ; p

2 / day

T directly after cooler: mapping recommended ;

Cold Clinker

T

5 / day

Insulated basket

Cooler Take off gas

T ; p ; flow

3 / day

Cooler Radiation

Surface T ; wind speed ; ambient T

1 / day

Bypass

Flow, T , p of quench air(s) and filter exit gas ; wall losses

1 / audit

Separate balance

heat

on

and

line

mass

•

Typical sampling frequency is shown in the next table for materials and fuels. Standard analysis like XRF should be carried out on every hourly sample in the plant. The recommended additional analysis to be carried out in the TC lab like CO2, H, S2-, TOC in kiln feed, ultimate fuel analyse, fuel ash analyse, ect are described in the kiln audit analyse template (Pyro 2 / Kiln Audit training).

•

Material Sampling:

Material: Recommended sampling frequency

Sample to TC:

•

KILN FEED

HOT MEAL (dry)

HOT MEAL (wet)

CLINKER

once per hour

twice per shift

twice per shift

once per hour

1 average sample out of all hourly audit samples

1 to 3 typical sample (dry sampling, no air contact)

1 to 6 typical sample - same time as dry sampling

1 average sample out of all hourly audit samples

Filter DUST (mill stopped) 2 samples during mill stopped

averge sample

BYPASS DUST once per shift

average sample out of all audit samples

Fuel Sampling

Material: Recommended sampling frequency Sample to TC lab:

coal or coke

solid shredded waste (plastic,…)

liquid fuel

solid biomass fuel

twice per shift

twice per shift

twice per shift

twice per shift

1 average 1 average sample 1 average sample 1 average sample sample out of all out of all audit out of all audit out of all audit audit samples samples samples samples

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KILN HEAT & MASS BALANCE – Page 14/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-1 – KILN HEAT & MASS BALANCE

6.

Kiln Heat Balance Example The example below shows the kiln audit result of Volos kiln 5, a 4 stage calciner line. The division heat balance tool is used for calculation. KILN AUDIT HEAT BALANCE TOOL - COOLER BALANCE AND PERFORMANCE SHEET Cooler input kg/h 350100 127000 0 0 5684 5140

Cooling fans Hot Clinker Exhaust air water injection False air Clinker Dust return (SA) Clinker Dust return (TA)

Total Out - In

T°C 27 1445 0

Cooler output Nm3/kgck 2,14 0,00 0,00

1445 1445

487924 0

2,14 0,00

kJ/kgck 73,86 1605,06 0,00 0,00 71,84 64,96

% 4,1 88,4 0,0 0,0 4,0 3,6

1815,72 0,00

100

Secondary air Tertiary air Mill take off #1 Mill take off #2 Exhaust air Cold clinker Wall losses Vap. Heat Dust secondary air Dust tertiary air Dust exhaust air Dust Mill take off 1 Dust MIll take off 2 Air leakage Total

kg/h 73329 66303 0 0 210468 122105

T°C 999 999 0 0 245 101,5

5684 5140 4895 0 0 0 487924

999 999 245 0 0

72,65%

Cooler Load, tday/m2 Air Load, Nm3/kgck

Cooling Efficiency, η Recovery Factor, k

95,21% 1,52

Average Blowing Density, Nm3/s/m2 Cooler Loss, kJ/kgck

Secondary air

0,41 Nm3/kgck 999 °C

Tertiary air

0,00 Nm3/kgck 0 °C

0,00 Nm3/kgck 0 °C

Exhaust air 1,29 Nm3/kgck 245 °C

127000 kg/h 1445 °C

Cold Clinker

Cooling fans

37,6 2,14 0,93 526,45

1,80 1,60 1,40 1,20 1,00 0,80 0,60 0,40 0,20 0,00 0,00

10,00

20,00

30,00

40,00

50,00

60,00

70,00

80,00

90,00

Cumulative Surface Area, m2

122105 kg/h 101,5 °C

2,14 Nm3/kgck 27 °C

% 34,8 31,5 0,0 0,0 22,8 4,2 1,5 0,0 2,4 2,2 0,4 0,0 0,0 0,0 100

BLOWING DENSITY OF THE COOLER

Mill take off #1 Mill take off #2

Hot Clinker

kJ/kgck 632,58 572,21 0,00 0,00 414,13 76,92 27,39 0,00 44,36 40,11 8,01 0,00 0,00 0,00 1815,72

2,00

Blowing Density, Nm3/s/m2

0,45 Nm3/kgck 999 °C

0,00 2,14

4587

Recovery Efficiency, ρ

excellent cooler

Nm3/kgck 0,45 0,41 0,00 0,00 1,29

KILN AUDIT HEAT BALANCE TOOL - KILN SYSTEM HEAT BALANCE System Out

System In H2O

kg/h 201746 811

Sensible Heat

13379

Combustion H2O

13379

Kiln Feed Total Fuel

T°C

Nm3/kgck 62 62

13654

0,97 0,95

53

0,00

kJ/kgck 80,34 1,66

heat% 2,2 0,0

T°C 395

Nm3/kgck kJ/kgck heat % 26,1 1,58 938,47

27,75%

109218

334,43

9,3

H2O

4,88%

7861

47,56

1,3

3459,34

93,6

SO2 (ppm)

70

40

0,09

0,0

0,18

0,0

N2

63,02%

157904

519,10

14,4

O2

4,28%

12252

36,76

1,0

CO 0,06% Heat Loss CO Preheater Exit Cooler Exhaust Air Cooler Exhaust Inj. Water Vap. Cooler Mill Take Off #1 Cooler Mill Take Off #2 Clinker-Cooler Exit Clinker Dust - Tertiary Air Dedusting Clinker Dust - Exhaust Gas Clinker Dust . Cooler Mill take off 1 + 2 Clinker Formation Heat Preheater Dust By-Pass Gas By-Pass Dust By-Pass Decarbonisation Heat Water Vaporization SNCR Water Vaporization Preheater Injection Water Vaporization Feed Moisture Wall Losses Tertiary Air Duct Preheater Kiln Cooler

156 156 210468

0,52 12,43 414,13 0,00 0,00 0 76,92 0,00 8,01 0,00 1697,80 25,49 0,00 0,00 0,00 0,00 0,00 15,89 404,85 50,00 168,00 159,46 27,39

182

62

0,01

48,42

S-2 Combustion

40 44920 22759 350100 0 0

62 12 74 27

0,00 0,27 0,14 2,14 0,00 0,00

4,17 4,29 13,32 73,86 0,00 0,00

0,1 0,1 0,4 2,0 0,0 0,0

Heat Consumption (fuels only, no TOC,S2-):

3459

kJ/kgck

Heat Consumption including TOC and S2-

3512

kJ/kg

Total Heat In

kg/h 287276

0,3

1,3

20

Preheater Exit Gas Gas Composition CO2

11,52

3523,64

TOC Combustion Total False Air Total Primary Air Total Cooling Air of Cooler Total Water Injection SNCR

content

245

1,29

0 0 122105 0 4895 0

0 0 101,5 999 245

0,00 0

8250 0 0

395 0 0

0 0 811

0,00

0,0

0,3 11,5 0,0 0,0 0,0 2,1 0,0 0,2 0,0 47,2 0,7 0,0 0,0 0,0 0,0 0,0 0,4 1,4 4,7 4,4 0,8

3697 Total Heat Out Difference % Deviation

© Copyright 2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

3594 -103 -2,87%

KILN HEAT & MASS BALANCE – Page 15/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-1 – KILN HEAT & MASS BALANCE

7.

Kiln Audit Results – Preheater / Calciner Kilns

The data below are the summary results of preheater and calciner kiln audits carried out since 2006, using the division tool with integrated database input sheet. The audits had been validated by TC before entering to the database. Present number of audits entered: 14 (preheater and calciner kilns, with grate cooler) The complete and actualized database is available on the portal – pyroprocessing domain for benchmark. The overview below will be updated yearly. CALCINER KILNS

STATUS 03-2010

CALCINER AND PREHEATER KILNS

Number of kilns

14

7

KILN AUDIT DATABASE

General

Unit

Average

Min

Max

Average

Spec. Heat consumption (fuel)

kJ/kg

3416

2820

3804

3304

Spec. Heat input kiln feed TOC

kJ/kg

87

0

482

105

Production

t/d

3060

1390

4260

3450

AF firing

%

13

0

60

7

Preheater Exit Gas Flow

Nm³/kg

1.65

1.41

1.85

1.59

Preheater Exit Gas Temperature (4 stage only)

°C

385 (n=13)

333 (n=13)

434 (n=13)

398 (n=6)

Top Cyclone Efficiency

%

91.5

87.0

96.0

91.1

False Air Preheater / Calciner

%

11.1

5.5

17.8

10.2

MW/m²

4.8

3.6

5.9

4.4

kg/kg

0.85

0.79

0.90

0.83

Heat of Clinker Formation

kJ/kg (%)

1776 (47.9)

1668 (44.7)

1988 (54.4)

1789 (49.0)

Kiln / PreheaterExit Gas

kJ/kg (%)

946 (25.4)

775 (21.7)

1186 (30.1)

941 (25.7)

Cooler Exhaust Air and Mill Take Off

kJ/kg (%)

405 (11.0)

335 (8.9)

499 (13.8)

416 (11.4)

Wall Loss

kJ/kg (%)

362 (9.8)

240 (6.4)

508 (14.0)

301 (8.3)

Kiln / Preheater Exit Dust Loss

kJ/kg (%)

55 (1.5)

26 (0.7)

93 (2.6)

60 (1.6)

Clinker after Cooler

kJ/kg (%)

104 (2.8)

54 (1.5)

143 (3.9)

106 (2.9)

Thermal Load CO2 (total) Heat Loss Distribution

Cooler

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KILN HEAT & MASS BALANCE – Page 16/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-1 – KILN HEAT & MASS BALANCE

Secondary Air + Tertiary Air Volume

Nm³/ kg

0.91

0.75

1.09

0.87

°C

923

827

1110

964

Nm³/kg

0.45 (n=7)

0.20 (n=7)

0.58 (n=7)

0.45

Tertiary Air Temperature

°C

930 (n=7)

832 (n=7)

999 (n=7)

930

Cold Clinker Temperature

°C

133

70

178

102

Hot Clinker Temperature

°C

1427

1390

1468

1429

Nm³/kg

2.1

1.6

2.5

2.1

%

70.5

66.0

77.1

70.4

1.37

1.22

1.60

1.42

Secondary Air Temperature Tertiary Air Volume (calciner only)

Cooling Air Recovery Efficiency K Factor

8.

Kiln Simulated Optimum Parameters

The values below are with 100% medium sulphur coke firing and typical raw mix burnability. Operation conditions are optimized (low false air, Oxygen on target, etc.). The cooler is a modern conventional cooler with k factor 1.5 and tertiary air take off from kiln hood. Specific heat consumption is not considering additional heat input at the raw mill shop (example Lepol kilns). PROCESS TYPE

WET

LONG DRY

LEPOL

4 STAGE PREHEATER

4 STAGE CALCINER

5 STAGE CALCINER

General

Unit

Spec. Heat consumption

kJ/kg

5400

3900

3400

3300

3300

3200

t/d

1000

1000

1000

3000

3000

3000

Kiln Exit Gas Flow

Nm³/k g

3.2

1.67

1.35

1.26

0.49

0.49

Kiln Exit Gas Temperature

°C

200

475 (before water spray)

1000

1000

1100

1100

Lepol / Preheater Exit Gas Flow

Nm³/k g

-

-

2.33

1.54

1.47

1.43

Lepol / Preheater Exit Gas Temperature

°C

-

-

110

350

360

310

37

33

15

16

15

14

rpm

1

1.4

1.4

2.5

3

3.5

%

35

0.5

14

0.5

0.5

0.5

Output

Kiln Length / Diameter Kiln Speed Feed Moisture

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KILN HEAT & MASS BALANCE – Page 17/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-1 – KILN HEAT & MASS BALANCE

Heat Loss Distribution Heat of Clinker Formation

kJ/kg (%)

1800 (32)

1800 (44)

1800 (51)

1800 (51)

1800 (51)

1800 (54)

Kiln / PreheaterExit Gas

kJ/kg (%)

940 (17)

1220 (30)

360 (10)

810 (23)

800 (23)

675 (21)

Cooler Exhaust Air

kJ/kg (%)

110 (2)

240 (6)

316 (9)

295 (9)

350 (10)

370 (11)

Wall Loss

kJ/kg (%)

700 (12)

470 (12)

300 (9)

340 (10)

250 (7)

275 (8)

Vaporization Feed Moisture

kJ/kg (%)

2050 (36)

20 (0.5)

630 (18)

20 (0.6)

20 (0.6)

20 (0.6)

Kiln / Preheater Exit Dust Loss

kJ/kg (%)

20 (0.4)

250 (6.2)

20 (0.6)

35 (1.0)

35 (1.0)

25 (0.8)

Clinker after Cooler

kJ/kg (%)

70 (1.1)

80 (1.9)

70 (2.0)

90 (2.7)

90 (2.7)

90 (2.7)

Secondary Air Volume

Nm³/k g

1.49

1.13

0.99

0.99

0.38

0.38

Secondary Air Temperature

°C

716

832

913

916

965

980

Nm³/k g

-

-

-

-

0.53

0.50

°C

-

-

-

-

965

980

Nm³/k g

0.61

0.97

1.11

1.11

1.17

1.21

Exhaust Air Temperature

°C

141

188

217

204

224

233

Cold Clinker Temperature

°C

90

100

90

120

120

120

Hot Clinker Temperature

°C

1390

1400

1435

1435

1450

1450

Nm³/k g

2.1

2.1

2.1

2.1

2.1

2.1

%

89

82

77

77

75

73

1.5

1.5

1.5

1.5

1.5

1.5

Cooler

Tertiary Air Volume Tertiary Air Temperature Exhaust Air Volume

Cooling Air Recovery Efficiency K Factor

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KILN HEAT & MASS BALANCE – Page 18/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-1 – KILN HEAT & MASS BALANCE

The next graphic shows the impact of different fuel, bypass and kiln size. Baseline is the optimized 3000 tpd 5 stage calciner line shown above – last column.

3600

kJ / kg clinker

Influcence on specific heat consumption

3500

3400

3300

3.000 t/d 5 stage calciner 100% medium S coke modern cooler

3200

3320

100% SSW

3080

100% coal

3430

1.500 t/d

3380

5% bypass

3380

3.000 t/d

3320

no bypass

3330

5.000 t/d

3200

3100

3000

9.

Baseline 1

2 Fuel Impact

3 Bypass

Kiln 4Size

+ 120 kJ / kg - 120 kJ / kg

+ 60 kJ / kg

+ 50 kJ / kg - 50 kJ / kg

References

Cement Portal

•

How to Perform a Kiln Audit

•

How to Optimise a Clinker Cooler

•

Lafarge Cooler Air Distribution Calculation Tool

•

Calciner / Preheater Heat Balance Tool

•

Wet and Lond Dry Heat Balance Tool

•

Pyro-Process I & II Division Training

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KILN HEAT & MASS BALANCE – Page 19/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-1 – KILN HEAT & MASS BALANCE

My notes:

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KILN HEAT & MASS BALANCE – Page 20/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-2 – VOLATILE CYCLES & CONTROL

3-2. Volatile Cycles & Control

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VOLATILE CYCLES & CONTROL – Page 1/19 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-2 – VOLATILE CYCLES & CONTROL

Table of Contents 1.

2.

3.

4.

5.

Properties of Volatiles Elements ...............................................................3 1.1

Basic Volatile Properties................................................................................. 3

1.2

Eutectic ........................................................................................................... 3

1.3

Vapor Pressure............................................................................................... 4

1.4

Parameters Influencing the Volatilisation Process ......................................... 4

Volatilization Process .................................................................................5 2.1

Volatile Recirculation Model ........................................................................... 5

2.2

Salts formation:............................................................................................... 6

2.3

Evolution of Volatiles During Transitions........................................................ 6

2.4

Volatile Cycle Time ......................................................................................... 7

Sulfur & Build Ups.......................................................................................7 3.1

Sulfur Volatilisation ......................................................................................... 7

3.2

Build-up and Rings ......................................................................................... 9

Modifications to Reduce Build-up ...........................................................11 4.1

Dirty back end:.............................................................................................. 11

4.2

Meal curtain .................................................................................................. 11

Kiln Bypass................................................................................................11 5.1

When is a Bypass Required? ....................................................................... 11

5.2

Bypass sizing................................................................................................ 11

5.3

Probe location............................................................................................... 12

5.4

One Step or Two Step Cooling..................................................................... 12

5.5

Control of Chloride Concentration ................................................................ 13

5.6

Bypass Dust Handling .................................................................................. 13

5.7

Bypass Gas Treatment................................................................................. 13

5.8

Impact Upon Operating Parameters............................................................. 13

6.

Lafarge bypass data (part 1) ....................................................................14

7.

Lafarge bypass data (part 2) ....................................................................15

8.

Volatile Balance Example .........................................................................16

9.

References:................................................................................................18

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VOLATILE CYCLES & CONTROL – Page 2/19 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-2 – VOLATILE CYCLES & CONTROL

1.

Properties of Volatiles Elements

1.1

Basic Volatile Properties

•

The raw mix and the fuels come with some minor elements (potassium, sodium, sulphur and chlorides) called volatiles.

Element

Na

Compound

Weight

Melting Point °C

Boiling

Heat of Formation

Point °C

- ∆H°f kJ/mol

Na2O

62.0

820

d

416

Hydroxide

NaOH

40.0

322

1390

427

Carbonate

Na2CO3

106.0

851

d

1131

142.0

884

—

1385

58.4

801

1465

411

Chloride

Na2SO4 NaCl

Oxide

K2O

94.2

887

d

362

Hydroxide

KOH

56.1

410

1327

426

Carbonate

K2CO3

138.2

891

d

1146

147.3

1069

1689

1434

74.6

776

1410

1436

Sulphate Chloride

Ca

Molecular

Oxide

Sulphate

K

Formula

K2SO4 KCl

Oxide

CaO

56.1

2580

2850

636

Hydroxide

Ca (OH)2

74.1

d

—

987

Carbonate

CaCO3

100.1

d

—

288

—

1430

1600

795

—

—

Sulphate Chloride

CaSO4

Fluoride

CaC12

136.1 111.0 78.1

CaF2

d≈ 1280 (1450) 772 1380

d=Decomposes, s=Sublimates

1.2 •

Eutectic In a multi-component-system the melt formation is governed by eutectics. Eutectic is a mixture of two or more substances that have a melting point lower than any of the substances of the mixture. System

Concentration

Melting point

(% mole)

(°C)

Na2SO4 — CaSO4

52 — 48

900

K2SO4 — CaSO4

58 — 42

867

K2SO4 — Na2SO4

23 — 77

823

K2CO3 — CaCO3

60 — 40

750

K2CO3 — Na2CO3

42 — 58

710

K2SO4 — KCl

40 — 60

690

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VOLATILE CYCLES & CONTROL – Page 3/19 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-2 – VOLATILE CYCLES & CONTROL

1.3 a)

KCl — CaSO4

68 — 32

688

KCl — NaCl

50 — 50

640

NaCl — Na2SO4

65 — 35

630

KCl — CaCl2

25 — 75

600

NaCl — CaCl2

50 — 50

500

Vapor Pressure Vapor Pressure for Volatile Compounds at Different Temperatures

mm Hg 760 700

NaOH

KCl

KOH

600

NaCl 500 Na 2CO3

400

Caution: This graphic is for trend indication only. We have no indication of the precision of the curves. Do not use for calculation.

Na 2SO4

300 200

K SO

K2 CO3

2

4

Thus, for instance, K is more volatile than Na.

100

700

800

900

1000 1100 1200 1300 1400 1500 °C

b) Typical Chemical Reaction Me n (SO4 )m ↔ n MeO + m SO 2 +

• •

where: Men can be: Ca, K2,Na2

The equilibrium constant of that reaction has this formula:

1.4 a)

m O2 2

n m m/2 [ MeO] [SO2 ] [O2 ] K= Men (SO4 )m

Parameters Influencing the Volatilisation Process Influence of kiln gases on the volatility of the circulating elements

Kiln atmosphere

Sodium

Potassium

Sulphur

Chloride

vapor pressure

v

v

v

v

CO2 ⇑

⇓

⇓

⇑

H 2O ⇑

⇑

⇑

⇑

O2 ⇓

⇑

⇑⇑

SO2 ⇑

⇓

⇑

The sulphur over alkali ratio (SAR) has also a major impact on the sulphur volatilization when SAR>1, the higher the SAR, the higher is the SO3 volatilisation.

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VOLATILE CYCLES & CONTROL – Page 4/19 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-2 – VOLATILE CYCLES & CONTROL

2.

Volatilization Process

•

Volatiles will start to volatilize (evaporate) from the liquid phase as soon as the temperature increases. A fraction of those elements (or compounds) will be vaporized in the burning zone and get entrained with the gases toward the back of the kiln. The vapors will cool down together with the gas stream and recondense before leaving the kiln or in the dust collector. The condensation takes place on any cool surface, mostly on the dust carried by the gas. - Fi : flux of volatile component i brought by fuel (g/kg ck) - Mi : flux of volatile component i brought by raw mix (g/kg ck) - Ci : flux of volatile component i going out with the clinker (g/kg ck) - Li : flux of volatile component i lost with gas and dust (g/kg ck) ( loss) - Ki : flux of volatile component i in the kiln load (g/kg ck) - Gi : flux of volatile component i in the gas stream (g/kg ck)

•

2.1

Volatile Recirculation Model

Exit gas & dust

Gas & dust

Trapping Raw mix

• Clinker: C =

Volatilization Kiln load

tF +M 1 − vt

• Kiln load: K =

Fuel

1− v (tF + M ) 1 − vt

Clinker

• Gas stream: G = • Losses: L =

a)

vM +F 1 − vt

1−t (vM + F ) 1 − vt

Example of volatilization and trapping coefficients

Type of kiln

SO3

K2O

Na2O

Cl-

T

v

t

v

t

v

t

Wet kiln without dust wasting

v 0.59

0.76

0.45

0.81

0.12

-

0.99

-

Wet kiln with dust wasting

0.72

0.63

0.53

0.51

0.24

0.68

0.99

-

Long dry kiln

0.65

0.87

0.65

0.81

0.21

0.45

0.99

-

Preheater kiln

0.80

0.90

0.69

0.96

0.26

0.79

0.99

0.99

Precalciner kiln

0.55

0.96

0.49

0.98

0.55

0.60

0.98

0.99

(Prepared from average volatile balances made within Lafarge)

b)

Typical concentration factors of volatiles in the kiln load (kiln load / raw mix ratio)

Na2O and K2O

2 to 10

SO3

4 to 20

Cl-

20 to 100

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VOLATILE CYCLES & CONTROL – Page 5/19 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-2 – VOLATILE CYCLES & CONTROL

2.2

Salts formation

The empirical relation is used to calculated the priority order of appearance of salts in the kiln load : Order of appearance / consumption KCl K

Cl

K2SO4 K

S

Na2SO4 S

CaSO4

NaCl

K2O r

Cl

Na

CaCl2

Na

Na2SO4

Na

Na2O r

Na2O r

S

CaSO4

From this priority order of formation of compounds, the volatilisation coefficient can be calculated for each salt.

2.3 •

Evolution of Volatiles During Transitions If M(θ) is a step at θ = 1 then:

K ( θ ) = K1 + (K0 − K1 )(vt )θ / T where: - K0 : previous kiln load composition - K1 : new kiln load composition - θ : time (to avoid confusion with t, the trapping coefficient) - T : the time required by a given mass of volatile to complete a cycle - M(θ) : flux of volatile from the raw mix at time θ - F(θ) : flux of volatile from the fuel at time θ - K(θ) : flux of volatile in the kiln load at time θ •

Circulating kiln load: 1.7 to 2.1 kgload/kg clinker. K =(100/(100-HotMLoi))*(1+(KD/1000)) where: - K : kiln load composition in kgload/kg clinker - HotMLoi : Hot meal LOI in % - KD: Kiln dust at the kiln back end in gdust/kg clinker

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VOLATILE CYCLES & CONTROL – Page 6/19 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-2 – VOLATILE CYCLES & CONTROL

Rules of thumb • LD kilns generated dust Lafarge NA average: 0.6, (from 0.2 to 1.34). • Preheater Kilns generated dust:: 200 - 400 g/kgck • Calciner AS Kilns generated dust:: 100 - 200 g/kgck • Lepol Kilns generated dust: 20 - 40 g/kgck Also note that figures greatly depend on kiln inlet geometry, gas velocity, clinker granulometry… Bypass dust weighing can give some indication of kiln inlet dust load.

2.4

Volatile Cycle Time C=

•

t 1−v

t is the time between the trapping and the burning zone v is the volatilization coefficient C is the cycling time

-

3.

Sulfur & Build Ups

3.1

Sulfur Volatilisation

•

Chlorine:

v = .99

5-6 days

SO3 :

v = .6

5-7 hours

Sulfur is found in: - Clinker raw material (combined form of sulfur or sulphate). - Combustibles (S in the form of organic components).

a)

Sulfur Behaviour

Sulfur Input Locations to Precalciner

30-40% capture

Feed: as SO4 , 90-95% capture as FeS 2 , 35-60% capture Fuel

RM

Fuel: as SO 4 or S, 90-95% capt

100

Formation in the Burning zone The following is the thermodynamic equilibrium of sulfur species in a 10% excess air flue gas. The principal product formed in the burning zone will be SO2 .

% of total sulphur

•

80

H2SO4

SO2

SO3

60 40 20 0 400

600

800

1000

1200

Temperature (ºK)

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VOLATILE CYCLES & CONTROL – Page 7/19 Version September 2010

1400

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-2 – VOLATILE CYCLES & CONTROL

b) What Affects the SO2 Generation in the Burning Zone? The composition of the kiln load •

Sulfur is preferably linked with alkalies which have a higher stability and a greater chance of being found as alkali sulphate in the clinker ( K 2 SO4 , Na2 SO4 ) themselves being part of bigger So if the kiln load composition has a molar excess of K 2O − Na2O available (not

compounds.

combined with chlorine) vs SO3 , the SO2 generated from the load will be lower (sulfur, alkali, molar ratio < 1.2). The burning zone temperature •

At lower temperature, less CaSO4 or alkali sulphates will decompose to form SO2 and the SO3 level in the clinker will be higher.

The O2 level 2000

v

SO 3

1.0

S 1500 O2 pp m 1000

1400°C

0.8 0.6

500

0.4

0

0.2

0.0

0.5

1.0

1.5 2.0 Oxygen %

2.5

3.0

0 0

1.0

2.5

1200°C 1000°C %O2 5.0

The residence time in the burning zone •

The longer the time the material stays in the burning zone, the higher the chance for SO2 to volatilize.

Back-end •

If the raw mix contains sulfur compounds (i.e. FeS2 = pyrite), the combustion of these compounds generates SO2 .

SO3 Volatilization due to the Calciner efficiency SO3 volatilization (%)

90 80 70 60 50 40 90

91

92

93

94

95

96

97

98

99 100

Combustion efficiency (%)

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VOLATILE CYCLES & CONTROL – Page 8/19 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-2 – VOLATILE CYCLES & CONTROL

c) Trapping

SO2 is stable above 900ºC but starts to be trapped by CaCO3 and CaO at lower

Lab experience (H. Ritzmann, Neubeckum).

temperatures. There is a large excess of CaCO3 in the preheater, which explains a high trapping coefficient (95% "dry" scrubbing).

80

SO2 trapped (% of total)

•

60

40

20

0 400

500

600

700

800

900

1000

Temperature (ºC)

•

CaCO3 + SO 2 + 1 / 2 O 2 → CaSO4 + CO 2 .

•

In a precalciner kiln, the decarbonated limestone captures SO2 more actively, especially with a high level of Oxygen and the following equilibrium is shifted to the left: CaSO4 ↔ CaO + SO2 + 1 / 2 O2 .

•

For this reason, precalciner kilns are able to absorb rather high concentrations of SO2 in the gas coming from the kiln.

3.2 Build-up and Rings a)

Limits of volatile components:

Total input, clinker basis, without Cl bypass AS Calciner - ILC

SP kiln

Usual limits

Maximum limits*

Usual limits

Maximum limits*

Sulphur (as SO3)

1.25%

1.9%

1.5%

2.25%

Chlorine (as Cl)*

0.025%

0.035%

0.025%

0.035%

* The maximum limit is possible with reasonable clinker burnability and favourable SAR

b) Sulphur/alkali ratio (SAR) The sulphur combines in priority with alkali as K2SO4 and Na2SO4. The excess sulphur forms CaSO4 that is much more volatile. Thus, volatilisation and build-up will be affected by both the overall quantity of volatile and by the sulphur in excess of alkali (SAR>1.2). SAR= (SO3/80) / (K2O/94+Na2O/62)* *Be careful, FLS formula is significantly different. In case of significant SO3 (>0.5%on clinker), the impact of SAR on the kiln operation is the following: SAR<1.5 1.5<SAR<2 SAR >2

Comfort zone Difficult zone Challenging zone

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VOLATILE CYCLES & CONTROL – Page 9/19 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-2 – VOLATILE CYCLES & CONTROL

* SAR<1 will create some quality problem. Refer to the Quality section. In case of high chlorine, an additional parameter can be monitored: The SAR –Cl on hot meal formula should be considered as the alkali will first react with Cl. For this reason, an increase of Cl in the system deteriorates the Sulphur volatilisation: SAR-Cl= (SO3/80) / (K2O/94+Na2O/62-Cl/71)

c)

Hot meal (bottom stage) follow-up

In case of high volatile input and/or high SAR, hot meal should be regularly tested (SO3 and Cl) and plotted with reference curve (plant specific) to assess the level of build-ups and act accordingly (for instance reduce Cl if hot meal very close from the cyclone blockages plant specific level) 8 7

Blue - plant w ith by-pass Black - plants w ithout by-pass RED/GREEN LINE original curves for build up limits.

Cl [%]

6 5

• Retznei Ø2009(2 strings)

Cizkovice

4 3

Malogoszcz - K2

2

Kujawy

Manner sdor f - K9 Hoghiz

1

Malogoszcz - K1

Medgidia - K10

Trbovlje

Wössingen

0 0.0

2.0

4.0

6.0

8.0

10.0

12.0

SO3 [%]

d) • •

• •

Build-ups mechanisms and locations After condensation and before solidification of the volatiles, the dust particles will be sticky and tend to agglomerate on solid objects: kiln walls, chains or lower cyclones of preheater tower. The sulphur build-up usually occurs where the temperature is between 800°C and 1100°C: kiln walls and chains for a long kiln, smoke chamber and lower cyclone for a preheater kiln. In those build-ups, the following sulphates are most commonly found: Arcanite (K2SO4), Anhydrite (CaSO4), Glaserite (K3Na (SO4)2), Ca-Langbeinite (K2Ca2 (SO4)3) and sulphate spurrite (Ca2 (SiO4)3 CaSO4). In a long kiln, the build-ups are formed below the internal exchanger. This takes place in the kiln load so the build-ups formed this way are naturally destroyed in the majority of the cases. In small diameter kiln, however, a sulphate ring can appear. Chlorine will condense in the 600°C to 700°C range, which is in the chains for a long kiln.

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VOLATILE CYCLES & CONTROL – Page 10/19 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-2 – VOLATILE CYCLES & CONTROL

4.

Modifications to Reduce Build-up

The following levers are used to reduce build-up for a given volatilisation: these solutions do not necessarily reduce volatilisation but only reduce the build up.

4.1

Dirty back end

The purpose of “dirty” backend is to promote the dust generation at the kiln back end. The good dust-to gas contact will reduce temperature and decrease the concentration of volatile in the kiln load. The limerich dust will trap gaseous sulphur and chlorides. Dirty back end can be achieved by chain, sluice gate or lifter in the kiln inlet.

4.2

Meal curtain

The purpose of meal curtain is quite similar to dirty back end, but uses stage 3 material (for a 4 stage preheater). This material is splashed into the riser in the lowest possible location, but ensuring that all the meal is taken by the gas (no meal bypass directly to the kiln) For more details refer to the “Build-up Control TA study”.

5. 5.1

Kiln Bypass When is a Bypass Required?

• When the total chloride input (fuel + raw mix), actual or future, is in the range of 250 - 350 g/t clinker a chloride bypass may be necessary to avoid operational issues with build up.

• In plants with higher levels of chloride input, a bypass may also be necessary to avoid excessive chlorine in the clinker

• A volatile balance should be conducted to help determine the need and sizing for a bypass. In

addition, the hot meal sulfate vs chlorine graph and build up tendency will give additional sizing information by determination the maximum Chloride/SO3 level for controlled kiln operation.(see Hot Meal ) This graph is unique to every plant.

5.2

Bypass sizing

• Quantity of Kiln gases assumed for sizing: • Precalciner kiln 0.5 – 0.6 nm3/kg clinker • Preheater kiln 1.2 – 1.3 nm3/kg clinker

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VOLATILE CYCLES & CONTROL – Page 11/19 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-2 – VOLATILE CYCLES & CONTROL

As a guide the size of bypass is given by: Precalciner Kiln Chloride Input g/t clk

Bypass Size %

<250

Not required

<700

5

<1300

10

<1800

15

Suspension Preheater Kiln Chloride Input g/t clk

Bypass Size %

<250

Not required

<1400

5

<2600

10

<3700

15

The assumptions used in the table are listed below, but these need to be adjusted according to the plant requirements: 1) Target chloride concentration in clinker 250 g/t 2) Chloride volatilisation factor for preheater kiln 99%, for precalciner kiln 98% 3) Bypass gas dust concentration 200 g/Nm3 Actual dust extraction from a bypass varies significantly from plant to plant and is normally in the range of 150 – 300 g dust /Nm3 gas. For a new bypass it is recommended that the dust transport capacity is sized for an extraction of 450 g dust /Nm3 gas extracted, except when a cyclone is used. The targeted maximum chloride input level is limited by the capabilities/costs for by-pass dust treatment (adding to cement/disposal). In correspondence the designed by-pass size shall provide sufficient low chloride levels in the hot meal to guarantee a controlled operation. To optimize this level the mentioned chloride vs. SO3 and build up tendency graph shall be set up, follow up period at least half a year.

5.3

Probe location

On top of smoke box on kiln side, distant from second lowest meal feed point and meal curtain to avoid any dust mixing. In the case of the presence of a reduction zone for NOx take care to avoid possible quench air leakage back into riser. Low velocity take-off is less sensitive to build up, but not so flexible for retro-fitting or re-location. Viceversa for the high velocity take-off design. In case of back end AF firing high velocity take-off have the risk of sucking in unburned fuel particles.

5.4

One Step or Two Step Cooling

One step cooling to below 200°C reduces the risk of dioxin and furan formation and is recommended by Lafarge. Two step offers potential to reduce SO2 emissions, if diluted by-pass gas is leaving the kiln line through or after the raw mill.

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

VOLATILE CYCLES & CONTROL – Page 12/19 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-2 – VOLATILE CYCLES & CONTROL

5.5

Control of Chloride Concentration

The quantity of dust collected in the bypass filter can by adjusted by use of a cyclone with an adjustable short circuit gasflow, or adjustable collection efficiency (either by variable inlet area or adjustable vortex finder length). The change in dust carry over also allows some control over the chlorine since it is predominant in the finer fraction. Normally the hot meal chloride has to be kept below 1.5% to avoid build ups.

5.6

Bypass Dust Handling

Dust is normally proportioned back into the cement mills. A global Chlorine balance is required to estimate the maximum possible dust addition to cement, taking into account seasonality and product portfolio. However, this solution is becoming more limited as chloride limits in cement and concrete are becoming lower. An alternative solution that avoids addition to cement is dust washing as practiced in Japan. Lean phase, pneumatic conveying can be used for dust transport, for chloride content below 10%. A simple rotary valve and feeding shoe with a well designed pipeline has been successful. A proprietary solution using a horizontal rotary valve has also been used effectively. Keep dust transport systems as short as possible, transport air needs to be dry (using a cooler and dryer). Use of mechanical transport if chloride >10% Assuming standard dust extraction the chloride concentration in the by-pass dust after filter will be typically below 10%. Installations with limited capabilities to treat the extracted by-pass dust might install a de-dusting cyclone before the filter unit and send back the dust to the kiln, increasing the chloride concentration, > 15%, in the remaining fine dust. The other possibility achieving a too high chloride concentration is a too low dust extraction caused by the real dust distribution in the kiln back end. In such a case dilution with kiln feed dust improves the behaviour in the transport line, dilution till the chloride concentration is < 10%.

5.7

Bypass Gas Treatment

Avoid a separate bypass stack. Solutions used in Lafarge:

• Raw mill inlet, plus lime hydrate addition to lower SO2, risk of dioxins and furans • Cooler front end, to avoid SO2 and D&F, but risk of cooler plate blockages Use bag filter for dust collection with approach velocity 0.9 m/min. Bag design for 240 °C,, operation at 180-200 °C.

5.8

Impact Upon Operating Parameters

Fuel consumption increase

• Precalciner kilns : 10 -14 kJ/kg clinker per 1% bypass • Preheater kilns : 20 - 28 kJ/kg clinker per 1% bypass Power consumption increase

• 1.5 kWh/t clinker approx.

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

VOLATILE CYCLES & CONTROL – Page 13/19 Version September 2010

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

[m³/h] [°C] 2 [m ]

[Nm³/h] [°C] [-] [Nm³/h] [%] [%] [%] [%]

[Nm³/h] [°C]

[t/h] [m³] [t/h] [t]

40

[Nm³/h] [mbar]

Dust amount(Mix) Dust storage size Dust amount(calc.) Storage capacity

22000 (18744) 230 (208)

[Nm³/h] [°C]

[t/h] [Y/N] [-]

~4,4 (3.51) 1

[m/s] [-]

(kiln feed) 500 0,555 (pure)

N not included

pneumatic

n.a n.a n.a n.a n.a n.a inlet wet scrubber 25 700 (5% mix 25%KF) 9% 4.25% 0.53% separate bag filter 50 000

(67900) 3700 (2818) 5 (4.15) 150 (163)

[Nm³/h] [Nm³/h] [%] [g/Nm³]

[tpd] [kJ/kg KK]

Retznei KSPH 1400 3400 ATEC / PMT

n.a.(0.5) n.a. n.a.(1) n.a.

N not included

n.a n.a n.a n.a n.a n.a before RM 40 000 3 - 7 %(4.03) 3.6 7.04% 0.57% separate bag filter 40 000 220 840 0.95

20000 (18744) 220(208)

(42900) 2400 (2200) 5 (5.1) < 400 (175)

MBM (idem PMT)

Mannersdorf KPAS 2500

(0.075) Yes (0.075) 30m3

N -

0.52 (0.17) Yes 0.52 50.17) 25 + 10

by tankers 2.5 N -

separate bag filter

separate bag filter

by tankers

397.9 350 (<350) Probe Fan 33540 20 n.a n.a n.a n.a Yes 82500 150 After p/hFan 42766 15 (15-30)

1

137500 6876 (4126) 5 (3) 200 (41)

Okke Line 4 KPAS 5500 3268 Taiheiyo

3784 (3660) 350 (<350) Probe Fan 3784 (3784) 15 Cold Air (10080) (130) Air bleed n.a n.a n.a Coal mill Stack 14948 (14948) (20)

1

Tagawa KPAS 4200 3268 Taiheyo 1996 (80500) (1200) (1.5)

(7.25)

Mech to truck

EP

(6-11%)

(140) main stack

(28)

FLS 2002 (101000) (23700) (23.5) (306)

Alexandria KPAS 4840

(10.3)

Mech to truck

EP

(10%)

Own BP stack

(4 - 7 now 20 - 22)

Beni Suef KPAS 4080 4100 Kobe (FLS type) 1993 (119000) (47600) (40) (216)

2,5 probe 0,25 cyc (0.35 then 1)

pneumatic

Bag Filter

15 - 20% (15%)

150° (dioxin)

350

24.8

Le Havre KSPH 3600 3430 (Taiheyo / CLE) 2001 165000 8250 5 300

6.

Extraction speed Quenching Step 1 Quenching air Temperature(Gas exit) Quench air fan size(1) max. flow max. press Step 2 Cooling air Temperature(Gas exit) Cooling air fan size(2) Heat Exchanger(Air2Gas) Cooling air Temperature(Gas exit) Gas Reintroduction Fan Flow Bypass Dust ClBypass Dust SO3 Bypass Dust K2O Bypass Dust Na2O Dedusting (sep./comb.) Type Size Temperature Filter Area Specific area load Dust transport type Transport capacity Dust mixing Dust type(Mix)

By-p ass Design (Operation ) Plant Name Kiln type Production Heat consumption Supplier(Engineering/Quenching) Year commissioned Kiln exit gas Extracted kiln gases % of kiln exit gases Dust amount

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-2 – VOLATILE CYCLES & CONTROL

Lafarge bypass data (part 1)

VOLATILE CYCLES & CONTROL – Page 14/19 Version September 2010

By-pass Design (Operation) Plant Name Kiln type Production Heat consumption Supplier(Engineering/Quenching) Year commissioned Kiln exit gas Extracted kiln gases % of kiln exit gases Dust amount Extraction speed Quenching Step 1 Quenching air Temperature(Gas exit) Quench air fan size(1) max. flow max. press Step 2 Cooling air Temperature(Gas exit) Cooling air fan size(2) Heat Exchanger(Air2Gas) Cooling air Temperature(Gas exit) Gas Reintroduction Fan Flow Bypass Dust Cl Bypass Dust SO3 Bypass Dust K2O Bypass Dust Na2O Dedusting (sep./comb.) Type Size Temperature Filter Area Specific area load Dust transport type Transport capacity Dust mixing Dust type(Mix) Dust amount(Mix) Dust storage size Dust amount(calc.) Storage capacity

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

[t/h] [Y/N] [-] [t/h] [m³] [t/h] [t]

[m³/h] [°C] 2 [m ]

[%] [%] [%] [%]

[Nm³/h] [°C] [-] [Nm³/h]

[Nm³/h] [°C]

[Nm³/h] [mbar]

[Nm³/h] [°C]

(0.53)

Bag Filter

10% (2%)

180 (180) before raw mill

180 (180)

(0.48)

N

(4.2) 0.63% 2.16% 0.13% comb cyclone

before ID Fan

(6880) (338)

Kirchdorf KSPH 974.2 3330 KHD 1962 (48710) (1650) (3.4) (290)

N not included n.a. n.a. (1) n.a.

n.a n.a n.a n.a n.a n.a before raw mill 78 000 7.4 (4) 3.6% 7.0% 0.6% separate bag filter 40 000 220 840 0.95

39 700 200

5300 5.00 < 300 < 3 [m/s]

IMMB(Polish)

Malogosczc KSPH 2200

N (0.25° Yes (0.25) 30m3 => 6t

by tankers

252

separate bag filter

Yes 29400 (19800) 180 Separate stack 9000 (6000) (15-20)

n.a Unknown

5400 (3600) (<400) Probe Cooling Fan 5400 10

(166667) (1380) (1.0) 300 1

Kanda KSPH 3200 3427 Home Made

0,73%KK

7.3%

before ID fan

30

5000 5.00

KHD modified

Karsdorf

3.55

1.9% eq Na2O

1% 11%

41667 0,08 Nm3/kgKK 20.00 160

39472 0,2 Nm3/kgKK 60.00 150

3.3

0.95 to 1.3

150 separate stack

Exshaw PCAS 2500 3884 FLS / 1981

Davenport PCAS 2842 3330 FLS / 1981

7.

[Nm³/h] [Nm³/h] [%] [g/Nm³] [m/s] [-]

[tpd] [kJ/kg KK]

Sugar Creek KPAS 2812 3344 (ATEC) 2005 52725 5325 (2500) 10% (4.3%) 200 (200)

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-2 – VOLATILE CYCLES & CONTROL

Lafarge bypass data (part 2)

VOLATILE CYCLES & CONTROL – Page 15/19 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-2 – VOLATILE CYCLES & CONTROL

8.

Volatile Balance Example

Volatile Balance Example : Davenport 1997 Flow t/h 168.500 105.075 22.000 0.000 3.810

Loss of ign % * 35.410 0.000 5.210 5.000 0.000 5.200

Moisture % 0.000 0.000 0.000 0.000 0.000 0.000

SO3 % 0.897 0.610 2.450 1.440 0.000 11.230

Coal Coke

Flow t/h 8.680 3.720

Ash (as rec) % 10.460 0.510

Moisture (as rec) % 5.570 4.590

S (as rec) % 1.020 3.040

K2O (ash) Na2O (ash) Cl % % (as rec) % 2.100 0.290 0.000 1.100 2.780 0.000

Stack

Flow SO2 kg/h 908.18

Dust (dry) kg/h 0.00

Dust SO3 % 0.00

Dust K2O % 0.00

Dust Na2O % 0.00

Flow dry t/h 168.5 22.0 8.2 3.55 0.00 105.08 22.00 3.81 1.14 -

CO2 % 35.4 5.0 0.00 0.00 5.00 5.20 0.00 -

Flow CO2=0 t/h 108.83 20.90 1.13 0.30 0.00 131.17 105.08 20.90 3.61 1.135 130.72

Flow t/h 168.2 22.0 8.7 3.7 .0 105.3 22.0 3.8 1.1 -

Flow dry kg/kgkk 1.60 0.21 0.08 0.03 0.00 1.00 0.21 0.04 0.01 -

Raw mix Clinker Kiln load Recirculated dust Injected prod Waste dust

K2O % 0.500 0.710 1.099 0.580 0.000 2.073

Na2O % 0.090 0.130 0.760 0.100 0.000 0.493

Dust Cl % 0.00

Cl % 0.001 0.010 0.101 0.001 0.000 0.255

Loss of ign % * 0.00

Mass Balance

Raw mix Recirculated dust Coal Coke Injected prod Total inlet Clinker Recirculated dust Waste dust Stack Total outlet

Flow Rate Adjustment Weighting Raw mix Recirculated dust Coal Coke Injected prod Total inlet Clinker Recirculated dust Waste dust Stack Total outlet *Ignition loss at:

0.50 0.00 0.00 0.00 0.00 0.50 0.00 0.00 0.00 1.0 %CO2 °C

««| (Coal; Flow CO2=0: Ash + S converted to SO3 + Cl) ««| (LWF; Flow CO2=0: Ash + S converted to SO3 + Cl)

(Stack; Flow CO2=0: Dust + SO2 converted to SO3 + Cl) ¯Inlet-outlet: 0.44 (st/h LOI=0) Flow CO2=0 Flow CO2=0 t/h kg/kg kk 108.61 1.03 20.90 0.20 1.13 0.01 0.30 0.00 0.00 .000 130.94 1.24 105.30 1.00 20.90 0.20 3.61 0.03 1.14 0.011 130.94 1.24

note - data entry • Enter weighting factors in boldface • total must equal 1.0 • all positive values 0-1

note - data entry on "Ignition loss" • Concerns LOI determination; impacts the CO2=0 mass balance • if %CO2; LOI is only CO2 loss • if 1050; LOI is CO2 & moisture loss • if 1400; LOI is CO2 & moisture & volatile loss

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VOLATILE CYCLES & CONTROL – Page 16/19 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-2 – VOLATILE CYCLES & CONTROL

Kiln Audit November 1997 Volatile Balance kiln load hypothesis

Waste Dust 4.063 = Stack = 10.231

=

17.304

31.362

Return Dust = 3.009

Raw Mix = 14.783

1.30

SO3

kg/kg clinker

Combustible =

Volatilization = 26.208

Trapping = 14.058

Clinker = 5.642

Kiln Load =31.850

17.792

Volatile Coefficient =

Total Trapping Coefficient 0.544 =

5.154

0.823

K2O Waste Dust =

0.750

1.962

Combustible =

7.202

0.173

Stack = 0.000 Return Dust = 1.212

Raw Mix = 7.831

Volatile Coefficient =

Total Trapping Coefficient 0.896 =

=

kiln load hypothesis

1.30

Na2O

0.387

8.615

Return Dust = 0.209

Raw Mix = 1.444

Clinker = 7.254

Kiln Load =14.283

9.043

Waste Dust 0.178 = Stack = 0.000

Volatilization = 7.029

Trapping = 5.240

0.492

kg/kg clinker

Combustible =

Volatilization = 8.586

Trapping = 8.228

Clinker = 1.294

Kiln Load =9.880

1.652

Volatile Coefficient =

Total Trapping Coefficient 0.979 =

0.028

0.869

Chlorine Waste Dust 0.057 = Stack = 0.000

0.059

Return Dust = 0.002

Raw Mix = 0.095

1.275

Total Trapping Coefficient 0.955 =

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

0.018

Volatilization = 1.257

Trapping = 1.216

0.097

Combustible =

Clinker = 0.056

Kiln Load =1.313 Volatile Coefficient =

0.957

VOLATILE CYCLES & CONTROL – Page 17/19 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-2 – VOLATILE CYCLES & CONTROL

9.

References

Please refer to the following reference documents on the Cement Portal for more detailed information:

• How to Burn Petcoke • How to Control Hot Meal • Combustion Manual (post Sevilla 1997) • Technical Agenda Study build-up control • Technical Agenda Study Pre-calciner • Technical Agenda Study Gas Bypass

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VOLATILE CYCLES & CONTROL – Page 18/19 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-2 – VOLATILE CYCLES & CONTROL

My notes:

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VOLATILE CYCLES & CONTROL – Page 19/19 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-3 – KILN SYSTEMS

3-3. Kiln Systems

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

KILN SYSTEMS – Page 1/18 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-3 – KILN SYSTEMS

Table of Contents 1. Kilns General .................................................................................... 3 1.1 Kiln Residence Time and Material Load ........................................................... 3 1.2 Kiln Thermal Load ............................................................................................. 4

2. Suspension Preheater & Precalciner Kilns.................................... 5 2.1 2.2 2.3 2.4 2.5

Pressure Drop and Temperature Profile ........................................................... 5 Splash Box ........................................................................................................ 6 Trapping Efficiency............................................................................................ 6 False Air ............................................................................................................ 7 Calciners ........................................................................................................... 8

3. Wet & Long Dry Kilns .................................................................... 11 3.1 Chain Design Guidelines................................................................................. 11 3.2 Lafarge Chain System Data ............................................................................ 14

4. References...................................................................................... 17

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KILN SYSTEMS – Page 2/18 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-3 – KILN SYSTEMS

1. 1.1

Kilns General Kiln Residence Time and Material Load

Kiln Residence Time (Peray) Residence Time

•

T=

0.19 ∗ L N ∗d ∗S

with:

ƒ ƒ ƒ ƒ

L Kiln length (m) N Kiln speed (rpm) d kiln diameter inside refractory (m) S Kiln slope (m/m)

Rules of thumb:

•

Calciner kilns: 30 min ; 3 – 5 rpm

•

Preheater kilns: 45 min ; 2 - 3 rpm

•

Lepol kilns: 60 min ; 1.25 – 1.5 rpm

•

Long kilns: 2 - 4 hour, 1 – 1.5 rpm

Kiln Material Load (in sintering zone, without coating, with Peray retention time)

ϕ=

T *P *100% 1440 * A * L * ρ

ϕ– Kiln material Loading [%] T – Kiln residence time (Peray) [min] L – Kiln length [m] P – Production [t/d] A – Kiln area inside refractory [m2] ρ – Clinker density – preset to 1.4 [t/m3]

Rules of thumb:

•

Calciner kilns: 4 - 6 %

•

Preheater kilns: 3 - 5 %

Be careful, results from other formulas (FLS, etc.) can differ significantly. Other formula can be based on “as raw mix”, with or without coating or with different retention time.

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KILN SYSTEMS – Page 3/18 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-3 – KILN SYSTEMS

1.2

Kiln Thermal Load

•

Defined as main burner heat rate divided by kiln cross-sectional area (inside brick diameter).

•

High heat rate can lead to premature brick failure.

•

Suggested maximum limits (for short and long dry kilns):

ƒ

Recommended < 5 MW/m2

ƒ

Max 6 MW/m2

Some kilns (wet process) can operate above this limit but requires a much longer BZ or stretched out flame. Care required in such cases – any effort to shorten the flame when operating above this limit will lead to rapid brick failure. Secondary air temperature also influences the total thermal loading to the front of the kiln. This is why some exceptional wet kilns can operate >6 MW/m2 and some AS kilns may be highly sensitive even at values <5MW/m2.

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KILN SYSTEMS – Page 4/18 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-3 – KILN SYSTEMS

2.

Suspension Preheater & Precalciner Kilns

2.1 •

Pressure Drop and Temperature Profile The Dp through a cyclone for a family of similar cyclones with identical dust load:

Dp = cst ∗ r ∗

Q2 D4

where:

ƒ ƒ ƒ ƒ

Dp is the pressure drop through the cyclone r is the fluid density Q is the gas flow D is the diameter of the cyclone

- 52 mbar 310°C

•

The pressure drop of a cyclone is considered from cyclone gas entry (gas inlet just before the cyclone) until the cyclone outlet (gas outlet just above the cyclone roof).

•

Typical pressure loss of a modern top cyclone is 7 to 9 mbar and of a modern intermediate cyclone 5 to 6 mbar.

•

The pressure drop of a preheater stage is the total pressure loss cyclone + corresponding riser duct measured just below the splash box.

•

Typical pressure loss of a modern top stage including riser duct loss is 12 mbar and of a modern intermediate stage 7 mbar.

•

A typical pressure and temperature profile of a modern 5 stage preheater after calciner is shown opposite

-40 mbar 480°C

- 33 mbar 630°C

- 26 mbar 750°C

- 19 mbar 860°C

The actual values for a plant can differ significantly due to higher amount of specific exit gas, false air, ongoing combustion (example kiln feed TOC and S2- or CO calciner exit) and poor preheater efficiency (gas or material bypass, poor meal splashing, poor dedusting efficiency,…). Rule of thumb: An increase in specific exit gas amount (example change of fuel, etc.) by 0,1 Nm³/kg increases the preheater exit gas temperature of the preheater by 17°C.

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KILN SYSTEMS – Page 5/18 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-3 – KILN SYSTEMS

2.2

2.3 •

Splash Box ƒ

A proper splash box ensures that the meal coming from the stage above is properly dispersed in the riser duct to the cyclone. A good dispersion guarantees the best possible heat exchange – the heat exchange should be finished before entering the cyclone.

ƒ

Design Criteria: + Meal pipe above splash box oriented 60 to 70° to the horizontal plane + Free distance in meal chute of 2,5m to the flap + Flat bottom

Trapping Efficiency ht =

Di − Do Di

Where:

ƒ

Di is the dust load of gas at cyclone inlet

ƒ

Do is the dust load of gas at cyclone outlet

•

Top cyclones are designed to have high efficiency (and higher pressure loss) while intermediate cyclones and especially bottom cyclones have typical lower efficiency (75-85%) – depending on cyclone design and condition of the dip tube. Exact measurement or simulation of trapping efficiency of intermediate cyclones is complex and often impossible. Nevertheless the impact can be high – efficiency drop of the bottom stage from 75% to 60% (for example dip tube damage) increases the preheater exit gas by 10°C. Efficiency of stage 2 has strong impact on the top cyclone efficiency.

•

Recommendations for dip tube length: Æ Cyclone 1: > 100 % of gas inlet height Æ Intermediate Cyclones: 75% of gas inlet height Æ Bottom Cyclone: 50% of gas inlet height

•

To allow benchmark the top cyclone efficiency is directly calculated out of kiln feed, not considering the dust coming from stage 2:

Top Cyclone Efficiency

• •

Etc =

Kf − Do Kf

Where:

ƒ ƒ

Kf is the kiln feed Do is the dust load of gas at cyclone outlet

The target value for the trapping efficiency of the top cyclone is 95%. A poor top cyclone efficiency has not only negative impact on heat consumption, it impacts in addition kiln feed uniformity and power cost.

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

KILN SYSTEMS – Page 6/18 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-3 – KILN SYSTEMS

•

Most accurate measurement of the preheater exit dust is truck weighing of the kiln filter dust (and GCT dust) during raw mill and coal mill off.

2.4

False Air

Some excess air is required for proper combustion. The Oxygen target on kiln or calciner depends mainly on the fuel used (see fuel / burner chapter). False air is all unwanted air entry increasing the excess air above target or reducing the secondary/tertiary air used from the cooler.

The main sources: •

Kiln hood and kiln outlet seal false air. Typically 3-6% of the combustion air kiln. This false air directly reduces the amount of secondary air.

•

Kiln inlet seal false air: Typical 2-4% of kiln exit gas. For calciner kilns it directly reduces tertiary air, for other kiln types it increases the Oxygen content.

•

False air preheater / calciner. Is given in % of preheater exit gas. A well sealed preheater can reach 3%.

False air is a major cost factor: o

False air is limiting production. For sold out plants 1% less false air could result in 1% more production.

o

False air increases the power cost (5% preheater false air Æ + 0.5kWh/t)

o

False air increases the heat consumption, false air entry at bottom cyclone is more critical compared to the top cyclone (see graphic below).

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

KILN SYSTEMS – Page 7/18 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-3 – KILN SYSTEMS

False Air vs Fuel Consumption 3200 3180

Stage 5 Stage 4 Stage 3 Stage 2 Stage 1

Fuel Consumption MJ/t clinker

3160 3140 3120 3100 3080 3060 3040 3020 3000 0

1

2

3

4

5

6

7

8

9

10

False Air % Preheater Exit Flow

The simple formula below gives a first assessment for preheater false air or false air between cyclone stages. A more accurate and complex assessment taking into account further effects (example combustion of kiln feed Carbon and Sulfur, CO, kiln feed airlift,…) is done in the division heat balance tool. The result of this assessment can differ significantly from the simple Oxygen approach.

V

FalseAir

2.5 a.

= V Po int 2 *

(%O2 (%O2

Po int 2 Air

− %O2Po int 1)

− %O2Po int 1)

Calciners Calciner Types and Terminology

AT

Air Through: Calciner without tertiary air duct (older design, limitation due to high excess air in kiln)

AS

Air Separate: Calciner with tertiary air duct (all modern calciner)

ILC

In Line Calciner: Kiln exit gas is introduced into the calciner (main calciner type, simple and robust)

SLC Separate Line Calciner: Kiln exit gas is not introduced to the calciner, fuel is burnt in tertiary air only (can be built smaller, advantage of combustion in high Oxygen, operation disadvantage due to risk of meal or fuel drop out into tertiary air duct). A Separate Line Calciner can have a complete separate preheater string and ID fan or can be combined after the calciner with the kiln exit gas to a common preheater.

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KILN SYSTEMS – Page 8/18 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-3 – KILN SYSTEMS

Combustion Chamber (also called hot spot calciner): a part of the calciner is built as downdraft SLC with tangential introduction of tertiary air and meal, providing a hot core for combustion. The combustion chamber is then transferred into an In Line Calciner part. Gives advantage for petcoke but not necessarily for coarse alternative fuel. Vessel Type Calciner: calciner with low gas speed in the main section, around 5m/s. Promotes longer residence time for coarse fuel, recommended type for difficult AF. Riser or Gooseneck Type Calciner: Calciner with gas speed 10 to 16 m/s. Orifice: high gas speed zone at the calciner bottom to prevent material and fuel fall through, 20 – 35 m/s for ILC and 35 – 50 m/s for SLC.

b.

Calciner Combustion Efficiency

Definition: Percent of total heat input which is used in the calciner. Heat Input: Calciner Fuels, CO from kiln exit gas. Heat Loss: CO calciner exit, unburnt Carbon in hot meal. Target: > 95% The combustion efficiency is calculated in the division heat balance tool. Unburnt Carbon in hot meal is critical for volatilization and should be below 0,1%.

c.

Calciner Residence Time

The true residence time of fuel is significantly higher than the gas residence time, especially in case of vessel type calciner. However, fuel residence time is difficult to calculate so gas residence time is used to benchmark calciner size. Calciner residence time is expressed as gas residence time between orifice and bottom cyclone inlet. Calculation is based at calciner exit gas condition. Residence time [s] = Calciner volume inside refractory [m³] / Calciner exit gas flow [actual m³/s]. Typical recommended residence time: Coal, gas: >2sec Coke and AF < 5mm: >3sec AF> 5mm: >>3sec (typical design is 6 sec) Additional residence time of 1 to 2 sec is required in case of staged combustion and / or SNCR for NOx reduction < 400 mg/Nm³. For combustion chambers the residence time should be reported separately to the ILC part, for example 1,5sec combustion chamber + 4sec gooseneck. Many existing calciners show residence times significantly below these recommendations, although operation is still possible without excessive CO and hot meal Carbon (volatilization risk) by optimizing calciner parameters such as fuel fineness, tertiary air temperature, etc.

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KILN SYSTEMS – Page 9/18 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-3 – KILN SYSTEMS

d.

Calcination Degree

Definition: % of kiln feed CO2 which is already calcined in the hot meal.

CO 2kf − CO 2hm ⎤ ⎡ 100 * ⎢ ⎥ CO 2kf CD % = 100 * ⎢ ⎥ 100 − CO 2hm ⎢ ⎥ ⎢⎣ ⎥⎦ CO2kf:

CO2 of kiln feed

CO2hm:

CO2 of hot meal at bottom stage

The result is not the real calcination degree since the measurement is impacted by the amount of kiln and preheater dust, volatile cycles,… The target is plant specific, typical 90 - 92 %. Alternative methods like LOI instead of CO2 or calcination via hot meal Rietveld can be used for regular process follow up. The calcination degree should be regularly monitored and optimised; operation control of the calciner should remain on calciner exit temperature.

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KILN SYSTEMS – Page 10/18 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-3 – KILN SYSTEMS

3. 3.1

Wet & Long Dry Kilns Chain Design Guidelines Kiln Chain System design tool kit V-3.8 by S. Fujimoto 2009

Z = zone length (ratio of zone length to kiln diameter) 2 3 A = m /m C = chain length (as percent of kiln diameter) Wet Kiln

Zone Free Dust curtain

Dry Kiln

Plastic

Z A C Z

1 to 11 to 80% to 85% 1 to 4

Preheat

A C Z

5 to 8 55% to 70% 0.5 to

(lower section) Preheat (upper section) Radiation

1.5 15 < 75% n/a n/a n/a 2.5

A C Z A C Z A

to 10 70% 0.5 to 2.5 6 to 8.5 70% to 80% 1 8.5 to 11

C

70% to 80%

Total Length of Chain system As no. of kiln diameters As % kiln length

7

Wet Kiln

Dry Kiln

6 to 10 18% to 25%

5 to 8 17% to 22%

Total Surface and Total Weight

Wet Kiln

Dry Kiln

Global m2/mtpd Global kg/mtpd

2.5 to 2.8 110 to 130

2.3 105

to 2.6 to 110

How far down the kiln should chain be used? Vb = [(1.0807*P)^1.5]/35.315 Where Vb = Kiln effective volume below the chain system i.e. (m3) P = Standard kiln clinker production + 20% t/d (metric t)

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KILN SYSTEMS – Page 11/18 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-3 – KILN SYSTEMS

Example: Calculation of Chained Volume of Kiln Calculate the chained volume for a kiln 4m diameter x 150m long with a nominal capacity of 814 tpd, assume 200mm thick refractory lining:

Step 1: Calculate kiln volume =150*P*(4-2*0.2)^2/4 = 1527 m3 Step 2: Calculate Vb= [(1.0807*P)^1.5]/35.315 =[(1.0807*814*1.2)^1.5]/35.315 = 971 m3 Step 3: Calculate chained volume of kiln = 1527-971 =556 m3 (36%) The capacity of the kiln drive would also need to be checked

Rules of Thumb

•

Chain surface: 19m2/t for oval chains vs. 22-25 m2/t for round chains.

•

For small kilns, ratios are always lower than for larger kilns.

•

Ratios are higher for dry kiln compared to wet kiln.

•

Void sections are applied along chain zone aiming to:

ƒ ƒ ƒ ƒ

equalize gas temperatures serve as a buffer area to equalize varying rates of material transportation precipitate kiln dust allow for installation of thermocouples

•

1500 m of installed chains reduces the exit chain gas temperature by 100oC.

•

A properly designed chain system can lower the SHC by 300 kcal/kg ck.

•

Heat exchange rate: 8.75 kcal/h/m2/C.

•

Pressure per one meter of chain10 to 20 Pa for curtain chain and 20 to 30 Pa for Gartand chain (note: Garland chains are abandoned due to practical considerations in maintaining hanging pattern).

•

For Gartand chain, the thermal effect is 1.5 time higher than curtain chain.

•

Wear rate: Wet Kilns average 84 g/t ck- range is typically 80-120 g/t ck Dry Kilns average 66 g/mt ck with a range as low as 17 g/t ck to a high of 133 g/t ck

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KILN SYSTEMS – Page 12/18 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-3 – KILN SYSTEMS

Other LNA Preferences Garland pattern not recommended Spiral curtain recommended for wet Kilns (promotes plastic zone movement) Zig-Zag dust curtain common for all wet Kilns Straight curtain style (offset in Alternating Rows) - in all zones – best for long dry Kilns One Chain length common in long dry Kilns Wet Kiln Chain Length is variable to allow material movement – See database 19 mm thickness X 76 mm diameter rings most common Plastic zone must be 25 mm to 38 mm thickness x 76 mm diameter or double chains per hanger Econoliners preferred instead of refractory for much longer service life

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KILN SYSTEMS – Page 13/18 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-3 – KILN SYSTEMS

3.2

Lafarge Chain System Data

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KILN SYSTEMS – Page 14/18 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-3 – KILN SYSTEMS

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KILN SYSTEMS – Page 15/18 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-3 – KILN SYSTEMS

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KILN SYSTEMS – Page 16/18 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-3 – KILN SYSTEMS

4.

References •

Preheater and Precalciner Priority Study

•

Precalciner Technical Agenda Study

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KILN SYSTEMS – Page 17/18 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 3-3 – KILN SYSTEMS

My notes:

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KILN SYSTEMS – Page 18/18 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 4 – PRODUCT QUALITY AND DEVELOPMENT

4. Product Quality & Development

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PRODUCT QUALITY & DEVELOPMENT – Page 1/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 4 – PRODUCT QUALITY AND DEVELOPMENT

Table of Contents 1. Chemical Characterization ................................................................ 3 1.1. 1.2. 1.3. 1.4. 1.5. 1.6. 1.7. 1.8. 1.9.

Ignition Loss .................................................................................................... 3 Silica Ratio ...................................................................................................... 3 Alumina-Iron Ratio........................................................................................... 3 Lime Saturation ............................................................................................... 3 Total Alkalies as Na2O .................................................................................... 3 Percent Liquid ................................................................................................. 4 Bogue Formulas .............................................................................................. 4 K 1450 Burnability Index ................................................................................. 4 Other Indicators............................................................................................... 6

2. Particle Size Distribution ................................................................... 7 2.1. 2.2. 2.3.

Rosin-Rammler Number ................................................................................. 7 Specific Surface Area...................................................................................... 7 Blaine Surface Area ........................................................................................ 8

3. Sulfate ................................................................................................. 9 3.1. 3.2.

Clinker Sulfates ............................................................................................... 9 Sulfate Addition ............................................................................................... 9

4. Cement characteristics.................................................................... 11 4.1. 4.2. 4.3.

Standards requirements................................................................................ 11 Cement Strength ........................................................................................... 11 Color.............................................................................................................. 12

5. 10 Basic Facts on Clinker................................................................ 13 6. Advance Indicators .......................................................................... 14 6.1. 6.2.

Raw mix and clinker ...................................................................................... 14 Finished products .......................................................................................... 15

7. Cement Standards............................................................................ 16 8. References........................................................................................ 19 8.1. 8.2. 8.3.

Lafarge Quality Technical Standards (LQTS) ............................................... 19 Knowledge..................................................................................................... 19 Tools.............................................................................................................. 19

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PRODUCT QUALITY & DEVELOPMENT – Page 2/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 4 – PRODUCT QUALITY AND DEVELOPMENT

1. Chemical Characterization •

KSt I ( Kühl ) =

•

In the following formulas: where:

S = SiO2, M = MgO, A =Al2O3, K = K2O,

ƒ

F = Fe2O3, N = Na2O3, C = CaO

•

when not specified: % is in weight in the raw mix. Refer to the “LQTS XRF analysis” and “LQTS Free lime by complexometry method”.

A includes ( TiO 2 + P2 O 5 )

KSt III =

•

ƒ

100 * ( C + 0.75 M ) 2.8 S + 1.18 A + 0.65 F

It takes MgO into account (when MgO < 2%).

1.1. Ignition Loss

•

Ignition loss = 0.786 * C + 1.092M + combined H2O+ organic matter.

120

CaCO3 → CaO + CO2

100

ƒ

% CO2 =

44 × %CaO 56

SR =

ƒ

ƒ

90

60

S (2.3 to 3.1) A+ F

0

If SR high, hard to burn, thin coating , poor clinker reactivity, higher specific heat consumption. If SR low easy burning but lower clinker reactivity and may cause unstable process conditions

30 25 20 15 10 5 0 -5 0 -10 -15 -20

A (1.3 to 2.0 ) F

20

40

60 80 C3S

100 120

Δbc vs C3S y = -0.2734x + 21.552 2 R = 0.9606

Δbc Δ

AR =

R2 = 0.9485

70

1.3. Alumina-Iron Ratio •

y = 0.3367x + 71.6

80

1.2. Silica Ratio •

LSF vs C3S

110 LSF

•

100C 2.8S + 1.1A + 0.7 F

If AR high with low F then lower liquid phase, high viscosity.

1.4. Lime Saturation

20

40

60

80

100 120

C3S

(On Raw Mix analyses, except C3S) •

C 3 S = 4.07 C − (7.6 Ssol + 6.72 A + 1.43 F )

ƒ

It is the potential C3S content of clinker when the free lime is zero and calculation LOI=0.

•

100C LSF = 2.8 S + 1.18 A + 0.65 F

•

Δbc = ƒ

1.5. Total Alkalies as Na2O •

Total as Na 2 O eq = Na 2 O + 0.658 K 2 O

Rule of thumb •

+ 0.1% Total Alkali in clinker : -0.5 to -1MPa at 28days

100 * ( 2.8 S + 1.65 A + 0.3 F − C ) S + A+ F +C

It should range between –4 and +4 depending on fuel ash and quality target.

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PRODUCT QUALITY & DEVELOPMENT – Page 3/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 4 – PRODUCT QUALITY AND DEVELOPMENT

1.6. Percent Liquid

1.7. Bogue Formulas

a) Calculation (Lea & Parker)

(On clinker bases, ref. Les Cahiers Techniques).

@ 1338ºC •

% liquid = 8.2 A − 5.22 F + M + N + K

a) Formulas • C 3 S = 4.07 C − (7.6 Ssol + 6.72 A + 1.43 F )

A/F>1.38 :

•

C 2 S = 8.6 Ssol 5.07 A + 1.08 F − 3.07C1

% liquid = 6.1 F + M + N + K

•

C 3 A = 2.65 A − 1.69 F

Liquid at 1338C influences the clinker granulation.

•

C 4 AF = 3.04 F

A/F<1.38:

• •

The formulas considered in BRS are:

with: ƒ C1 = Total CaO for raw mixes,

@ 1400ºC

% liquid = 2.95 A + 2.25 F + M + N + K

•

ƒ ƒ

@ 1450ºC •

% liquid = 3 A + 2.25 F + M + N + K

•

1450 C is most frequently used within Lafarge.

•

Optimum at 1450C: 25%.

% liquid = 1.13 C 3 A + 1.35 C 4 AF + M + N + K

b) Liquid phase impact If liquid phase too high:

ƒ ƒ ƒ •

Grindability ↓ (harder) 1-day strength ↓

6

modified

as:

K 2O < 1.176 not all SO3 combined as SO3 K 2 SO4 then SO3 in K 2 SO4 = 0.85 K 2 O

If

•

Remaining SO3 = SO3 − SO3 in K 2 SO4

•

ƒ

C3S formation speed ↓

ƒ

Clinker granulation ↓

SO3 in Na 2 SO4 = 1.292 Na 2 O

% free CAO 14

8

be

Na 2 O < 0.775 not all SO3 SO3 ( remaining ) combined as Na 2 SO4 :

Liquid Phase Constituent Impact

10

may

Step #2:

Clinker porosity ↓

If liquid phase too low:

12

F

F = Fe2 O3 − Mn2 O3

Step #1: •

•

And

b) SO3 combination

@ 1470 ºC •

ƒ ƒ

C1 = Total CaO - Free CaO for clinkers C1 = Total CaO - Free CaO - 0.7 SO3 for cements (CEMI) Ssol= soluble silica (silicate form only)

C3A C4AF K2O 18 % 5 %

1%

18 % 5 %

0%

5 % 18 % 1 % 5 % 18 % 0 %

4 2 0 1250 1300 1350 1400 1450 1500 1550 temperature °C

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

If

Step #3: •

CaO combined with excess SO3

= 0.7 * (SO3 − (SO3 in K 2 SO4 + SO3 in Na 2 SO4 ))

1.8. K 1450 Burnability Index a) Calculation This index is representative of the ability of the raw material to combine. The sample is heated (1000ºC/h) in a lab furnace at 1450 ºC for 30 minutes. After burning, the remaining free lime is measured. The ability to combine is determined by the reaction time of the following reaction: C 2 S + C → C 3 S

PRODUCT QUALITY & DEVELOPMENT – Page 4/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 4 – PRODUCT QUALITY AND DEVELOPMENT

Heat consumption difference (%)

If we accept that this reaction can occur only after all C 2 S is formed:

(ref. Cahiers techniques)

8 6 4

K1450 change 40

2 0 -2

0 -40

-4 -6 -8

-80

20

•

40

60

d[C ] = k [C 2 S ] • [C ] dt Rules of thumb

ƒ

[C2S] is the C 2 S concentration at t

ƒ ƒ

[C] is the lime concentration at t

[C o ]− [C ] = [C 2 S o ]− [C 2 S ] 56

ƒ

•

K 2 SO4 improves the burnability;

•

+1% SO3 lowers the combination temperature by 60C;

•

+1% K2O increases the combination temperature by 35C;

•

increase from 2 to 3% of silica reject at 63 microns lowers the K1450 by 30 points (cf graph);

•

+ 0.3% CaF2 addition in the raw mix (or 0.23F in the clinker) improves the K1450 by 10 to 60 points, lowering the burning temp by 30 to 130C. Unfortunately, it lengthens the setting time by 20 - 60min (for +0.1%F in the clinker in normal burning conditions).

k is a constant (function of temp).

172

with: ƒ [C°] is the concentration of lime at tº

•

+0.1 % +0.4 % +1 % +1.3 % +0.2 % +3 % fluor sol. Na2O Ex.SO3 Fe2O3 P2O5 quartz equiv. > 63 µ

80 100 120 140 160 180 200 Lafarge K

with:

•

b) Parameters influencing the Burnability

[C2S°] is the concentration of C2S at tº

[C ] + Δc = [C2 S ] 56

172

with: Δ

c

is the

Δ bc

relative at 100%

clinker: •

⎛S + A+ F +C ⎞ Δc = Δ bc.⎜ ⎟ ⎝ 100 − LOI ⎠

•

⎛ [C ] + Δc C o ⎞ 1 ⎜ ⎟ K= ln . 3.07 Δc ⎜⎝ C o + Δc [C ] ⎟⎠

Impact of fineness •

[ ]

[C] = The remaining free lime in a lab test in which the raw material is burned for 30 minutes at 1450ºC

Rule of thumb K < 30: 30 < K < 45: 45 < K < 70: 70 < K < 100: 100 < K < 140: 140 < K:

2.84 (SR − 1.8 ) + 0.27 Q45 + 0.12C125 + 0.12 Aq 45

where:

with: o ƒ [C ] = CaO - 1.87 SiO2

ƒ

Free Lime = [C ] − 1.89 + 0.48(LSF − 100 ) +

ƒ

Q45 = % quartz >45 μm

ƒ

C125 = % calcite >125 μm

ƒ

Aq45 = % non quartz, acid insoluble >45 μm (excluding dolomite)

Rules of thumb: Very bad burnability Bad burnability Medium burnability Good burnability Very good burnability Excellent burnability

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

•

%(quartz>63μm) < 2%,

•

%(quartz>45μm) < 2.5%

PRODUCT QUALITY & DEVELOPMENT – Page 5/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 4 – PRODUCT QUALITY AND DEVELOPMENT

Effects of % 100 µm rejects Quartz type raw mix

% free CaO 6 5

% free CaO 6

Effects of % 100 µm rejects Marl type raw mix

5

25 %

4

4

3

3 10 %

2

2

1

25 %

1

0 1350

5% 1400

1450

1500 1550 temperature °C

10 % 0 1350 1400

1450

1500 1550 temperature °C

1.9. Other Indicators Burnability Factor •

BF = ƒ ƒ

C3 S C 4 AF + C 3 A

Higher BF, harder to burn Generally BF increases with SR

Burning Factor •

= LSF + 10 SR -3*(MgO + Na2O + K2O) if >120 ´ harder to burn

ƒ

Hydraulic Modulus •

HM =

S + A+ F C+M

Cementation Index •

Cl =

2.8 S + 1.1 A + 0.7 F C + 1 .4 M

Coating Index •

CT = C3A + C4AF + 0.2 C2S + 2*Fe2O3 ƒ Optimum value between 28 to 30, ƒ if <28: light coating, ƒ if >30: heavy unstable coating, rings, snowmen

Alkali saturation

ƒ

Clinker basis calculation ´ Also refer to the “Volatilisation“ chapter (incrustation limits ´ effect of sulphur alkali ratio and chlorine upon build up)

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PRODUCT QUALITY & DEVELOPMENT – Page 6/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 4 – PRODUCT QUALITY AND DEVELOPMENT

2. Particle Size Distribution 2.1. Rosin-Rammler Number •

The Rosin-Rammler curve mathematically approximates most powder particle size distributions: ⎡d ⎤ −⎢ ⎥ d R = 100e ⎣ o ⎦

ƒ ƒ ƒ ƒ •

n

⎛ ⎛ 100 ⎞ ⎞ ln⎜⎜ ln⎜ ⎟ ⎟⎟ = n (In( d ) − In( d o )) ⎝ ⎝ R ⎠⎠

or

d R

= =

particle size (μm) % retained at d

do n

= =

particle size (μm) @ R = 100/e, approx. 36.8% Rosin-Rammler number

The formula allows PSD data to be represented as a straight line by plotting: (In (In 100 )) vs. In (d)

R ƒ ƒ

n can be calculated by the slope of the least squares line. The higher the RR number, the steeper the PSD as more particles are found into a narrow size range.

Rules of thumb •

RR# for high efficiency separator cement: 1.1 - 1.2

ƒ ƒ

RR# for Sturtevant circuit (raw or cement): 0.9 - 1.0 RR# for open circuit cement: 0.8 - 0.9,

•

dO = 12-36 μm

•

+ 0.15 point #RR increases the water demand by 2-3% (ref. Les Cahiers Techniques)

2.2. Specific Surface Area •

The following can be used calculate the Specific Surface Area (SSA), assuming spherical particles:

•

S i = 4πri2

•

4 M i = πri3 p 3

ƒ

Si

=

the particle surface area

ƒ

Mi

=

the particle weight

ƒ

ri

=

the particle radius

ƒ

ρ

=

the specific density of particles

For a size distribution with n particles

4 3 πri ρ Str = ni * Si = ni * 4πri2 Mtr = ni * 3

Str =

3 ∗ M tr ri ∗ ρ

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PRODUCT QUALITY & DEVELOPMENT – Page 7/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 4 – PRODUCT QUALITY AND DEVELOPMENT

•

•

6f

SSA =

ρ

R j − R j +1

16

∑d j =0

j

+ d j +1

ƒ

F = Form factor (close to 1)

ƒ

ρ

ƒ ƒ

do = 0.1 μm

d6 = 4 μm

d12= 48 μm

d1 = 0.3 μm

d7 = 6 μm

d13 = 64 μm

Ri = % retained at di

d2 = 1 μm

d8 = 8 μm

d14 = 96 μm

di = Particle size (μm)

d3 = 1.5 μm

d9 = 12 μm

d15 = 128 μm

d4 = 2 μm

d10 = 16 μm

d16 = 196 μm

d5 = 3 μm

d11 = 24 μm

= Specific density of cement (g/cm3)

The 0-3 μm fraction of normal Portland cement accounts for 60% of total surface.

2.3. Blaine Surface Area •

SSB = Blaine Surface Area (in cm2/g). It’s a permeability test. SSB is inversely proportional to the ability to pass air through a bed of particles. The correlation between calculated SSA and SSB is: SSA = 807 + 1.2 * SSB

•

For cements with n=1 Anselm found:

SSA =

36.8 * 10

where: -

4

do * n * ρ

-

do, n Rosin-Rammler distribution

ρ = specific density = 3.2 x103 kg/m3

Rules of thumb (Les Cahiers Techniques) •

The Blaine specific surface correlates well (r2 = 0.92) with the % passing 10 µm (same for 8 µm):

•

+ 1 % passing 10 µm = + 10.8 m2/kg + 100 m2/kg SSB Î Range +4 to + 15 MPa , (Averages 2-7 days +8MPa, 1 & 28 days +6 MPa pure cements). Warning: Cement sulphate addition must be increased with SSB: +100 m2/kg Î + 0.5 to +0.6% SO3. 2% gypsum results in +10m2/kg at 370m2/kg SSB.

Warning: The use of “weathered clinker” for cement production may significantly impact the measurement of Blaine Surface Area. In such case the ”Blaine” result looks very fine but 45µ residues are also high. In such case, when using weathered clinker, double checked with 45µ residue method Graph 1

Graph 2 18

15

15 12 45m R

12 9

9 6

6

3 3 3200

3400

3600

3800

4000

4200

4400

Blaine

4600

0 2500

3000

3500

4000

4500

Blaine

The graph1 displays an abnormal correlation between Blaine and 45µ residue. After investigation, the cause has been identified: use of a significant amount of “weathered clinker”. Graph 2 shows a normal correlation.

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

PRODUCT QUALITY & DEVELOPMENT – Page 8/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 4 – PRODUCT QUALITY AND DEVELOPMENT

3. Sulfate 3.1. Clinker Sulfates •

Possible forms of sulfates and alkalies:

ƒ ƒ

as alkali sulfates (small crystals of a few µm) inserted between the clinker phases as S and alkalies inserted in the crystal structures of silicate and aluminate phases Clinker rich in alkalies and… … poor in sulfates

… rich in sulfates

•

Little alkali sulfate

•

Much alkali sulfate

•

Uncombined alkali: N and K in orthorhombic C3A K in C2S

•

Little uncombined alkali: Little K and N in cubic C3A Little K in C2S

•

Inversed monoclinic C3S

•

Rhomboedric C3S

•

Some sulfur in the uncombined alkali S in silicates and aluminates

N and K in orthorhombic C3A Workability problems, plastic shrinkage

•

alkali sulfates Cubic C3A

orthorhombic C3A

alkali sulfates Cubic C3A

alkali sulfates Cubic C3 A

Clinker sulfate content Increase of early-age strengths

Clinker harder to grind

On the basis of the content of sulfur with respect to alkalies, and the relative proportions of sodium and potassium, alkali sulfates may be found under different forms:

ƒ

Thenardite : Na 2 SO4 . This sodium sulfate is rarely seen in clinker.

ƒ

Aphthitalite : Na 2 SO4 3 K 2 SO4 . Its composition may vary to (3 Na 2 SO4 K 2 SO4 ) .

ƒ

Arcanite : K 2 SO4 . It is observed when the SO3 / K 2 O molar ratio ranges between 1 and 2.

ƒ

Calcium langbeinite: 2 CaSO4 K 2 SO4 . This phase is encountered when the SO3 / sodium equivalent* molar ratio is greater than 2 and the sodium percentage low vis-à-vis potassium.

ƒ

Anhydrite: CaSO4 . It shows up only when the SO3 / sodium equivalent* molar ratio is greater than 3. Note: Calcium langbeinite form can be also found in sintered clogging/coating after falling from the pre-heater or kiln wall.

3.2. Sulfate Addition •

Gypsum and/or anhydrite - sulfates are added to control the setting process of the cement, primarily the rapid setting of the C3A component.

a) False set •

Early development of stiffness without the evolution of much heat. It can be dispelled and plasticity regained by further mixing without the addition of water [also called "grap set", "premature stiffening", "hesitation set", "rubber set"].

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

PRODUCT QUALITY & DEVELOPMENT – Page 9/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 4 – PRODUCT QUALITY AND DEVELOPMENT

b) Flash set •

Early development of stiffness usually with considerable evolution of heat. It cannot be dispelled nor plasticity regained by further mixing without adding water [also called "quick set"]. Reaction is: C 3 A + nH 2 O + C → C 4 A(H 2 O )n .

c) The Chemistry of False and Flash Set Components •

•

Hemihydrate and the anhydrites are the dehydrated forms of gypsum.

ƒ

Gypsum

ƒ

β -hemihydrate (plaster of Paris)

ƒ

Soluble anhydrite ( CaSO4 .III)

CaSO4 .( 0.001 _ 0.5 ) H 2 O

ƒ

Insoluble (natural) anhydrite

CaSO4

CaSO4 . 2 H 2 O CaSO4 .0.5 H 2 O

They react differently than gypsum when added to cement.

Reactions 4.5 4

Sulfate solubility

3.5

2.5 2

80 % Dehydr.

SO3 solution (g/l)

100

Gypsum Hemihydrate Soluble Anhydrite Natural Anhydrite

3

1.5 1 0. 0 1 2. 6 1 2 3 Time - Minutes

60 40 20 0 60

80

100

120 140 Temp. °C

160

180

•

Dehydration in the milling process can be thought as beginning at about 80 °C. However, gypsum dehydration is also a function of the time and % humidity of the surrounding atmosphere. Hemihydrate reacts differently than gypsum or anhydrite when water is added to cement, due to the differences in solubility. In the case of too much hemihydrate, which dissolves very quickly and in substantial quantities in the mix water, false set will occur. While too much hemihydrate will cause false set, not having enough SO3 available in solution will cause much more serious flash set.

•

How to determine the % of gypsum dehydration? Do refer to the National standards. Example of calculation % dehydration = 172.17 * LOI 250/ 36.04 (based on the molecular weights) LOI at 250 degree Celcius

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

PRODUCT QUALITY & DEVELOPMENT – Page 10/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 4 – PRODUCT QUALITY AND DEVELOPMENT

The following table gives schematic diagrams of the structure development of cement. The lattice work represents the ettringite crystallization, the platelets - tabular monosulphate and the rectangles - secondary gypsum.

Available sulphate in solution Low C3A

Hydration time 10 min

Normal set set Accelerated set set

set

Low SO3

Flash set set

Low C3A

workable

High SO3 workable

High C3A

3 hours

Low SO3 workable

High C3A

1 hour

Type of set

set

set

High SO3

False set set

set

set

Optimum sulfate •

S = 1.2(% sol Na 2 O equiv .) + 0.2 (% Al 2 O3 ) + 6.2 10 −3 (BSS ) − 0.7 .

•

The sulfate content roughly corresponds to the optimum for 3-day strengths.

•

How to conduct “Optimum sulfate trial?”? ´ Refer to the procedure, job aids and experience sharing

Use of grinding aid •

The Technical Agenda on “Grinding aid” provides key solutions / levers for optimizing the setting process when relevant

4. Cement characteristics 4.1. Standards requirements •

In each country, there are National Standards that shall be strictly applied according to the National Certification rules. Standards requirements are not negotiable!

•

Some Lafarge BUs due to Export markets shall comply with several Certification systems. For example, Langkawi plant in Malaysia shall comply to Malaysian, Indonesian, Nepalese and European standards. All those standards requirements are mandatory and not negotiable!

There are at least 2 worldwide “product” standards systems: ASTM and ISO-EN., see extracts - section 8

4.2. Cement Strength •

Theoretical water required to totally hydrate the cement: 35% weight of cement.

•

How to perform Compressive strength measurement? Refer to the corresponding LQTS (Lafarge quality technical standard).

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

PRODUCT QUALITY & DEVELOPMENT – Page 11/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 4 – PRODUCT QUALITY AND DEVELOPMENT

Parameters influencing the cement strength : A variation of X MPa StrengthÎ is produced by an increase of 1 point of: Sol Na2Eq (%)

1 day (MPa)

2 days (MPa)

10

10

7 days (MPa)

28days (MPa)

Compressive strength (MPa) 80

Tot Na2Eq (%)

-10

C3S

70

C3S (%)

0.1

0.3

0.4

0.6 60

C2S(%)

C2S

0.5 50

C3A (%)

0.5

0.3

0.7 40

C4AF (%)

Hydration of pure phases according to Boque and Lerch

-0.5 30

MgO (%)

-1.1

-1.0

SO3/totAlk Excess

1.1

1.3

FCaO (%)

1.1

-0.8

-0.6 20

D75Belite (μm)

-0.2

1.5

0

-0.2

-0.3

-0.3

C12A7 C3A

10

C4AF 7 28

90

180

360 days

4.3. Colour If % Fe 2 O3 is combined with Blaine specific surface (m2/kg), it is possible to explain 97% of the observed color variations. MgO content will also impact cement color as well as the reducing condition during the burning will give lighter color of the cement

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

PRODUCT QUALITY & DEVELOPMENT – Page 12/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 4 – PRODUCT QUALITY AND DEVELOPMENT

5. Ten Basic Facts on Clinker Warning: Here, MPa is European standard (1.45 EN MPa= 1 US/Can MPa)

1) Raw mix rejects

The reduction of raw mix rejects reduces the burning temperature and the cement grinding energy: 100 µm R in raw mix: 20% Ô 10% ´ - 4 kWh/t on both raw mix & cement grinding. This is particularly the case for siliceous rejects. This action is also rather favorable to strengths.

2) Heat profile

A short profile helps grindability and strength development. Slow cooling adversely affects strengths and workability. Clinkering level: 30 min. Ò 60 min. ´ - 3 to - 10 MPa in the laboratory.

3) Burning atmosphere

Production uniformity requires an oxidizing atmosphere because a reducing atmosphere promotes volatilization ´ "cyclic" operation, sulfate and alkali fluctuations, thus a non uniform clinker: SO3 variation in clinker from 1 to 4 % ´ variation in % alkali sulfates ´ possibility of large strength variations at 1 day.

4) Free lime content

An increase in clinker free lime content reduces both initial and final setting times + 1 % free CaO (up to 1.5%) ´ - 50 min on average (- 10 à - 100 min depending on clinker). Similarly, the addition of lime shortens both initial and final setting time.

5) Clinker

C 3 S content An increase in clinker C 3 S content (to the detriment of C 2 S ) improves strengths at 1, 2, 3 and 7 days:

+ 10% C 3 S ´ + 2 to + 5 MPa At 28 days, the increase is less noticeable since there is also a contribution from C2 S . 6) Clinker

C 2 S content At constant Blaine specific surface, grinding energy increases with C 2 S content. Inversely it reduces with an increase in C 3 S : + 10 % C2S ´ + 5 kWh/t for 350 m2/kg SSB

7) Clinker alkali content

Alkali always works against 28-day strengths no matter what form they are: + 0.1 % Na2O equiv. ´ - 1 MPa

8) Clinker alkali and sulfates

At optimum sulfate content for early ages, soluble alkalies, in particular in the form of sulfates, improve early strengths: + 0.1 % Na2O equiv. ´ + 0.5 - 1.5 MPa Strengths improve with an increase in the

9) Alkali saturation

Alkali molar saturation by clinker

SO3

C3 A

content.

facilitates control over workability:

Alkali saturation ´ Ô water demand and Ò fluidity and early-age fc. 10) Excess Sulfate / alkali

If clinker

SO3

is increased beyond alkali molar saturation, increased clinker fineness

and higher grinding energy can be observed. + 1 % excess

SO3 ´ + 4 to 5 kWh/t.

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

PRODUCT QUALITY & DEVELOPMENT – Page 13/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 4 – PRODUCT QUALITY AND DEVELOPMENT

6. Advance Indicators 6.1. Raw Mix and Clinker ADVANCE

1 N

KFUI =

KFUI =

KSUI =

E

D

C

B

A

>30

20-30

14-20

10-14

<10

>30

20-30

12-20

8-12

<8

>2

1.52.0

1.21.5

1.01.2

<1.0

N

∑ (C 3 S i − C 3 ST )2

or

i =1

5 N

N

2 ∑ (LSFi − LSFT )

i =1

σ SO3 × 100

1 + x SO3

fCaO.UI =

σ fCaO 0.1 + 0.2 × x fCaO3

Others

CUI .(clkC 3S ) =

1 N

N

∑ (C 3 S i − C 3 S average )2

< 16

i =1

Focusing on Uniformity Do also study the fluctuation of other key parameters such as Silica modulus, Alkalies, MgO and kiln feed fineness. Experience sharing ´ in 2007, a bad performance on kiln reliability was closely related to …K2O fluctuations! The cause was linked to the use of several clay sources. KFUI was “B/C”!

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PRODUCT QUALITY & DEVELOPMENT – Page 14/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 4 – PRODUCT QUALITY AND DEVELOPMENT

6.2. Finished products ADVANCE Strength uniformity 28 days

Addition Saturation Index ASX

EN basis standard deviation ASTM basis and others Standard deviation

E

D

C

B

A

>3.0

3.02.5

2.52.0

2.01.6

< 1.6

>2.5

2.52.0

2.01.7

1.71.4

< 1.4

Calculation

Interpretation

For each product:

Range of variation is fully independent from product type and product mix; Variation from 0 to100% for any product type.

ASX ( P ) =

Addition % Pr oduct − MIN addition %of s tan dard ×100 MAX addition % − MIN addition % of s tan dard

<0%: not reaching the standard lower limit requirement 0%: no benefit is drawn from this product type

Products mix of the entity (production site, BU, Region) Weighed average with the corresponding volumes for the global portfolio

100%: full benefit is taken from the product type >100%: means over passing the standard limit requirement

Potential Free Clinker PFK Maximum Potential C/K MPCK(E)

For each product:

PFK ( P ) = (% Clin ker present − % Clin ker MINimum in the s tan dard ) × Volume of Pr esently produced binder (t / y ) Add up directly the values of PFK(P) in the entity for all products to get the PFK for a given entity Results reported in tons/year Interpret result as the quantity of clinker that can potentially be saved for the same binder volume or used to produce additional cement

Total present volume of Binder produced (t / y ) MPCK ( E ) = × 100 Total present volume of clin ker used (t / y ) − PFK ( E )

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

For each product compute the PFK as described above but with ASX=100% then compute the PFK at entity level then compute MPCK(E) by entity Result reported without unit

PRODUCT QUALITY & DEVELOPMENT – Page 15/20 Version September 2010

Updated October, 2009

3.0

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY 5 - 15 (b)

3.0

4.5

4.5

12.0 (1740) 22.0 (3190)

7-day, min (p)

28-day, min (p) 28-day, C.V., max, % (p)

8.0

7.0 (1020)

3-day, min (p)

8.0

51.0

8.0

51.0

8.0

60.0

51.0

40.0

28-day, max (d)

40.0

40.0

7-day, max (d)

38.0 (d) 36.0

8.0

26.5

13.5 24.0

43.0

32.5

26.5

20.0

32.5

32.5

26.5

20.0

3-day, max (d)

28.0 (4060) (d) 28.0 (4060) (d)

20.0

250

45

(g)

(g)

0-5

1.5

3.0 (e)

1-day, max (d)

8.0

26.5

17.0 (2470)

26.5

91-day, min (d)

17.0 (2470)

28.0 (4060) (d)

14.5

60 600

28-day, min

14.5

45 375

12.0 (1740) 14.5

45 375

24.0 (3480)

20.0

10.0 (1450)

45 375

20.0

10.0 (1450)

60 600

45 375

5.0 (v) 1.0 (w)

12.0 (1740)

14.5

60 600

45 375

(g) (g)

0.0 - 5.0 (a)

19.0 (2760)

14.5

45 375

(g)

(g)

0-5

7-day, min

Maximum, minutes Compressive Strength, MPa (psi) (q)

45 375

(g)

(g)

0-5

0.60

3-day, min

60

600

Minimum, minutes

45

375

5.0 (v) 1.0 (w)

0.0 - 5.0 (a)

0.60

15 (c)

0.75

1-day, min

45

375

(g)

(g)

Maximum, minutes Setting Time, Gillmore Test (d)

(g)

(g)

5.0 (v) 1.0 (w) 5.0 (v) 1.0 (w)

0.0 - 5.0 (a)

0-5

0.0 - 5.0 (a)

Minimum, minutes

Setting Time, Vicat Test

PHYSICAL REQUIREMENTS

Inorganic Processing Addition, max, % Organic Processing Addition, max, %

Limestone, min-max, %

0.60

0.60

100

8

3.0 10.0

3.5

5.0

HE

5 - 15 (b)

10.0

3.0

3.0

HEL

0.75

2.5

2.3

6.0

6.5

IV

8.0

24.0

13.5

250

45

(g)

(g)

17.0 (2470)

7.0 (1020)

600

60

375

45

5.0 (v) 1.0 (w)

0.0 - 5.0 (a)

0.60

7 (h)

Heat Index, C3S+4.75(C3A) (s) C4AF+2(C3A)) or solid solution (C4AF+C2F), as applicable, max, % NaEq(Na2O+0.658K2O), max, % (d)

8

3.0 0.75

3.5

6.0

III

8.0

33.0 (d)

25.0

8.5

375

45

(g)

(g)

0-5

6

0.75

3.0

2.5

5.0

LH

LOW HEAT ASTM / AASHTO

40 (h) 8

3.0 0.75

3.0

MHL

CSA

C3A, max, % 8

3.0 0.75

3.0

5.0

MH

HIGH EARLY ASTM / AASHTO

C2S, max, %

0.75

3.0

5.0

MS

CSA

35 (h)

5 - 15 (b)

3.0 10.0

3.5

1.5

3.0 (e)

3.0

6.0

6.0 (h,k)

6.0

II (MH)

MODERATE

C3S, max, %

3.0

Insoluble Residue, max, %

3.5

0.75

Loss on Ignition, max, %

3.0

3.0

3.0

6.0

C3A > 8%

6.0 (k)

3

6.0

2

SO3, max,%,(j) when 3.0

II

MgO, max, %

5.0

GUL

ASTM/AASHTO

Fe O , max, %

C3A < 8%

CSA 6.0

I

GU

NORMAL

ASTM / AASHTO

Al2O3, max, %

CHEMICAL REQUIREMENTS

COMPARISON OF PORTLAND CEMENT SPECIFICATIONS ASTM C 150-09, AASHTO M 85-09 & CSA A3001-08

10.0

3.0

3.0

LHL

8.0

25.0

8.5

375

45

(g)

(g)

5 - 15 (b)

CSA

21.0 (3050)

15.0 (2180)

8.0 (1160)

600

60

375

45

5.0 (v) 1.0 (w)

0.0 - 5.0 (a)

0.60

25 (k)

5 (k)

0.75

3.0

2.3

6.0

V

8.0

51.0

40.0

32.5

26.5

20.0

14.5

375

45

(g)

(g)

0-5

5

0.75

3.0

2.5

5.0

HS

CSA

SULFATE RESISTANT ASTM / AASHTO

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 4 – PRODUCT QUALITY AND DEVELOPMENT

7. Cement Standards

*The data contained in the following tables is intended for information purposes; please consult the current version of the applicable Standards for the full and accurate reference.

PRODUCT QUALITY & DEVELOPMENT – Page 16/20 Version September 2010

LH

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY GU

HE

MS

45

45

28.0 (s)

20 (2900)

28 (4060)

7-day, min

28-day, C.V., max, % (m)

91-days, min

28-day, min

18 (2610)

17 (2470)

13 (1890)

3-day, min

11 (1600)

(r)

420

10 (1450)

(r)

420

1-day, min

Compressive Strength, MPa (psi)

(r)

Maximum, minutes

Air content (mortar), volume, max, %

45

420

Minimum, minutes

Setting time, Vicat test

PHYSICAL REQUIREMENTS HS

MH

LH

45

45

11 (1600) 22.0 (s)

25 (3620)

5 (725)

(r)

420

18 (2610)

11 (1600)

(r)

420

45

21 (3050)

11 (1600)

(r)

420

45

45

(f)

12 (f)

420

45

(f)

12 (f)

420

5.0 (720)

(f)

12 (f)

420

45

IT (≥70)

ASTM

IS (≥ 70)

AASHTO

ASTM /

(f)

12 (f)

420

45

MS

IT (P>S)

ASTM

IP

(f)

12 (f)

420

45

HS

ASTM / AASHTO

5.0

4.0 (c)

6.0

(b)

(b)

(b)

IT (P>S)

ASTM

IP (a)

ASTM / AASHTO

5.0 (w)

<95 ± 5.0 <40 ± 5.0

IT

ASTM

(f)

12 (f)

420

45

LH (k)

20.0 (2900) 18.0 (2610) 18.0 (2610) 11.0 (1600)

13.0 (1890) 11.0 (1600) 11.0 (1600)

(f)

12 (f)

420

45

GU

5.0 (w)

<40 ± 5.0

IP

ASTM / AASHTO

25.0 (3620) 25.0 (3620) 25.0 (3620) 11.0 (1600) 25.0 (3620) 25.0 (3620) 25.0 (3620) 21.0 (3050)

20.0 (2900) 18.0 (2610) 18.0 (2610)

13.0 (1890) 11.0 (1600) 11.0 (1600)

(f)

12 (f)

420

MS

IT (P<S<70)

ASTM

IS (< 70)

ASTM / AASHTO

1.0 4.0

3.0

2.0

2.0 1.0

4.0 (c)

3.0 (c)

(b)

(b)

Insoluble Residue, max, %

GU HS

IT (≥70)

IT (P<S<70) (b)

ASTM

ASTM

IS (≥ 70) (a)

AASHTO

ASTM /

5.0 (w)

IS (≥ 70) 70-95 ± 5.0

AASHTO

ASTM /

ASTM C 595-09 and AASHTO M 240-09

Loss on Ignition, max, %

Sulfide S, max, %

SO3 (CSA) - Sulfate as SO3 (ASTM), max, %

MgO, max, %

The chemical composition for the cement is not specified. However, the cement shall be analyzed for informational purposes.

LH

(b)

MH

CaO, max, %

HS

(b)

MS

Al2O3, max, %

HE

IS (< 70)(a)

ASTM / AASHTO

5.0 (w)

<70 ± 5.0

IS (< 70)

ASTM / AASHTO

(b)

GU

This performance specification covers hydraulic cements for both general and special applications, There are no restrictions on the composition of the cement or its constituents.

MH

SiO2, min, %

CHEMICAL REQUIREMENTS

Limestone, max, %

Fly ash content / content variation, % (q)

Silica fume content / content variation, % (q)

Pozzolan content / content variation, % (q)

Slag content / content variation, % (q)

MS

HS

ASTM C1157-08a

HE

BLENDED CEMENT PROPORTIONS

GU

Updated December, 2009

COMPARISON OF BLENDED HYDRAULIC CEMENT SPECIFICATIONS ASTM C 1157-08a and C 595-09, AASHTO M 240-09, and CSA A3001- 08

8.0

26.5

20.0

14.5

480

45

GUb

10.0

3.0 (n)

N

8.0

26.5

20.0

14.5

(l)

480

60

MSb

6.0

3.0 (n)

8.0

26.5

20.0

14.5

(l)

480

60

MHb

FA (F, CI, CH)

5 (w)

max. 70% ±5 max. 40% ± 2.5 max. 15% ± 1.5 max. 50% ± 2.5

8.0

38.0 (s)

24.0

13.5

250

45

HEb

3.0

1.0

2.0 (p)

3.0 (n.o)

S

CSA A3001-08 Binary

8.0

33.0 (s)

25.0

8.5

480

90

LHb

3.5

3.0 (n)

SF (SF, SFI)

8.0

26.5

20.0

14.5

(l)

480

60

HSb

6.0

3.0 (n)

Ternary

max. 60% *

max. 60% *

max. 60% *

max. 60% *

Ternary Quaternary

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 4 – PRODUCT QUALITY AND DEVELOPMENT

PRODUCT QUALITY & DEVELOPMENT – Page 17/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 4 – PRODUCT QUALITY AND DEVELOPMENT

EN 197-1 (2000) ´ Tables are extracted from BS EN 197-1

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

PRODUCT QUALITY & DEVELOPMENT – Page 18/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 4 – PRODUCT QUALITY AND DEVELOPMENT

8. References 8.1. Lafarge Quality Technical Standards (LQTS) •

XRF Analysis for In-coming materials, In-process materials and finished products

•

Free lime analysis by Complexometry method

•

Fineness by Blaine

•

Monitoring the quality of laboratory measurements

•

Effective quality control plan

•

Compressive strength measurement

8.2. Knowledge •

Lafarge product platform (problem analysis)

•

Technical Memento

•

Minor Elements Database

•

Cementitious Database

•

Grinding Aids Technical Agenda Study

•

Les Cahiers Techniques

8.3. Tools •

Concrete Predictive Model Database

•

EN conformity evaluation tool

•

Standards

•

Micro-concrete

•

Model for balancing trace elements in a plant

•

TYTP toolkit

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PRODUCT QUALITY & DEVELOPMENT – Page 19/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 4 – PRODUCT QUALITY AND DEVELOPMENT

My notes:

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PRODUCT QUALITY & DEVELOPMENT – Page 20/20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 5 – ENVIRONMENT

5. Environment

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ENVIRONMENT 1 /20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 5 – ENVIRONMENT

Table of Contents 1.

2.

3.

4.

5.

NOx ...............................................................................................................3 1.1

NOx generalities ............................................................................................. 3

1.2

NOx formation in the kiln ................................................................................ 3

1.3

NOx Formation in the Precalciner .................................................................. 5

1.4

NOx Abatement Methods ................................................................................ 5

SO2 ...............................................................................................................7 2.1

SO2 from combustion ..................................................................................... 7

2.2

SO2 from raw material.................................................................................... 7

2.3

Best Available Control Technologies (BACT) for SO2 emissions .................. 7

Dust ..............................................................................................................8 3.1

ESP................................................................................................................. 8

3.2

Baghouse...................................................................................................... 10

3.3

Hybrid filters.................................................................................................. 11

3.4

Gas Conditioning & Cooling ......................................................................... 11

Mercury ......................................................................................................12 4.1

Hg Generalities ............................................................................................. 12

4.2

Fate of Mercury in the Cement Process ....................................................... 13

4.3

Mercury Abatement Methods ....................................................................... 13

4.4

Regulation..................................................................................................... 13

Dioxins & Furans.......................................................................................13 5.1

Dioxins & Furans Formation ......................................................................... 13

5.2

Influencing factors of stack PCDD/Fs levels in cement kilns ....................... 14

5.3

Primary measures and process optimization to reduce PCDD/Fs............... 14

5.4

Regulations................................................................................................... 15

6.

Carbon Dioxide..........................................................................................15

7.

Others.........................................................................................................16

8.

7.1

Molar ratio calculation (DeNox Example)...................................................... 16

7.2

Correction to Standard Oxygen Conditions.................................................. 16

7.3

Continuous Emission Monitoring (CEMS) .................................................... 17

7.4

Emission Ranges for European Cement Kilns ............................................. 17

7.5

European AF Kiln Emission Limits ............................................................... 18

References .................................................................................................19 8.1

Lafarge Documents ...................................................................................... 19

8.2

External Documents ..................................................................................... 19

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ENVIRONMENT 2 /20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 5 – ENVIRONMENT

1.

NOx

1.1 NOx generalities •

Gross NOx emissions are typically in the range of 500 to 1,500 ppm being closely related to kiln combustion conditions.

•

In the cement industry normally, 95% of NOx formed is nitric oxide (NO). This gas is colourless and is readily transformed into NO2 in air.

•

Nitrogen dioxide (NO2) is a reddish-brown gas and is the principal component of smog. The toxic effects of NO2 are not completely known, but an exposure to 15 ppm NO2 causes eye and nose irritations and 25 ppm causes pulmonary discomfort.

•

Nitrous Oxide (N2O) represents <1% (typically 10 - 20 ppm) of NOx produced in a cement kiln. It is very stable and is considered to play a role in the destruction of ozone.

1.2 NOx formation in the kiln a) Thermal NOx formation mechanisms •

Thermal NOx is defined as that portion of the oxides of nitrogen that originate from fixation of atmospheric nitrogen. The principal reactions for the fixation of atmospheric nitrogen are generally recognised as follows (Zeldovich mechanism):

O + N 2 → NO + N N + O2 → NO + O

N 2 + O2 → 2 NO •

In an oxidising atmosphere NO is formed. ALL steps listed above are reversible in a reducing atmosphere, depending on exact temperature and partial pressure conditions at a given point in the flame.

•

Thermal NO formation kinetics are slow compared with fuel oxidation reactions and may be disassociated from the combustion process. Thus final NO concentrations never reach levels predicted by thermodynamic equilibrium at temperatures used.

•

Some studies (Fenimore, Bowman,...1971) found that the rates of thermal NOx formation in the primary flame zone were considerably higher than those in the post flame zone. This “fast NO” formation occurred at rates greatly exceeding the rate predicted by the O, N atom equilibrium mechanism. Some NO is formed before the O atom has had chance to form O2 (second hypothesis).

b) Prompt NOx formation mechanisms

•

Prompt NO is formed by the breaking of N2 bonds by “CH” hydrocarbonaceous radicals released primarily by the fuel instead of O2 radicals in practical terms the amounts are negligible (less than 100ppm).

c) Fuel NOx

•

The “fuel NOx” is due to the nitrogen conversion in the flame during the combustion. Nitrogen is mainly contained in aromatic compounds.

•

Rule of thumb : 0.2 to 2% N in fuel may yield 60 to 2100 ppm NO

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ENVIRONMENT 3 /20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 5 – ENVIRONMENT

•

Many fuels contain significant quantities of chemically bound nitrogen. Some oils can have nitrogen in excess of 2-4% and many liquid hazardous wastes can contain even higher levels. The following table shows the potential NO formation from different fuels, expressed in ppm of neutral combustion gas: FUEL

Nitrogen %

Potential NO ppm @ 0% O2

0

0

Fuel Oil

0.3 – 0.5

500 – 800

Fuel Oil

0.5 – 1.0

800 - 1600

0.5 – 2

1200 – 4900

1-2

1800 - 3600

Natural Gas

Coal Petcoke

d) What Affects the NOx Formation in the Kiln? 1

•

O2 level affects the formation of both fuel and 0.8 thermal NOx which is explained by the fact that NOx formation requires a free oxygen 0.6 atom. 0.4

•

Even if NO is formed, reducing conditions 0.2 (even local) and high temperature can produce NO separation into N2 and O2 – 0 lowering total NO produced.

Nox reduction in natural gas flame NA combustion book, p164

Nox/Nox ambient air

The Oxygen Level

Oxidant oxygen level (%)

21

20

19

18

Combustion air temperature 600

400 300

NO thermal

500 NO, ppm

NO (ppm)

Air Ar/O2

200 NO combustible 100

Air

400

Thermal NOx

300

Ar/O2

200 Fuel NOx

100

0 0

10

20 Excess air

30

NO formation with ambient air

40

0

0

10

20 30 Excess air

40

NO formation with preheated air - 275 °C

•

This shows that the preheated air increases thermal NOx but not fuel NOx.

•

Formation of thermal NOx is strongly dependent on the flame temperature and a few factors can affect it.

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ENVIRONMENT 4 /20 Version September 2010

50

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 5 – ENVIRONMENT

Flame Shape

•

The hotter the flame, the higher the NOx emission so the burner pipe settings affecting the flame shape also have an impact on the NOx emission: i.e. primary air, combustible fineness, volatiles content...

1.3 NOx Formation in the Precalciner •

NOx generated in the calciner is mainly fuel related. Thus we’d rather use low N content fuel.

•

About 60% of the fuel nitrogen is converted into NOx in a PH/PC tower (cf. Davenport Kiln audit 1997, 64%).

a) What Affects the NOx Generation in the Precalciner? CO Level

•

The CO presence (even ppm level) indicates reducing atmospheres which affects NO formation. Low-NOx precalciners create local reducing atmospheres to reverse NO formation. However, large amounts of CO are produced and thus require a low temperature post burn to control the quantity of CO emitted. Rule of thumb: 3 sec. residence time (Richmond FLS – ILC). Some FLS designed ILC in South America also employ 3 circuit burners, which are claimed to contribute to lower NO formation. It is possible to create reducing atmospheres in a calciner by relocating the fuel injection point.

Oxygen Level

•

The fuel nitrogen needs oxygen to be transformed into NOx so that the NOx level will increase with the oxygen level. This is true for conventional precalciner designs. This is not true for Low-NOx precalciners, since O2 levels include the excess air required for post burn.

Temperature

•

Some tests were performed by FLS. An increase of the precalciner flame temperature seems to reduce the NOx emission but this phenomenon is not yet well understood.

1.4 NOx Abatement Methods a) Methods For further details, see Technical Agenda: “NOx reduction techniques study”. Process Mastery 1)

Improve KFUI: permits the operator to burn consistently at a lower temperature.

2)

Improve mix burnability: lower clinkerization temperature (not always applicable).

3)

Improve clinker cooler stability: Minimize secondary air temperature fluctuations that can affect flame temperatures. For air separate precalciners, it stabilizes the tertiary air temperature.

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ENVIRONMENT 5 /20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 5 – ENVIRONMENT

4)

Avoid over burning: Points 1, 2. also consider burning practices and the employment of LUCIE.

5)

Reduce excess air

6)

Reduce Primary air – lower limit depends upon fuel burned

7)

Optimise burner settings

Modifications 8)

Lower Fuel Nitrogen

9)

Install a Low-NOx burner – high momentum with low primary air

10)

Inject water - limited application due to higher fuel consumption

11)

Whole tire injection (preheater kiln): Creates reducing atmospheres,

12)

Injecting fuel into lower part of kiln riser to create a reduction zone. Consider mid-kiln fuel injection on long kilns and above calciner in Lepol grates

13)

Staged Fuel Combustion (SFC): to create a long enough reducing atmosphere zone (NOx -> N2): <800mg/Nm3 with low reactive fuels and <500mg/Nm3 with high reactive fuels.

Post-combustion control technologies 14)

Selective Non-Catalytic Reduction (SNCR) with ammonia or Urea Injection. Optimum temperature ranges (850 to 950°C for urea and 900 to 1000°C for NH3). Ammonia emission (ammonia slip) can become an issue at the lowest NOx levels.

15)

Selective Catalytic Reduction (SCR) using NH3 in presence of a catalyst with potential for low NOx emission (pilot plants with 90% NOx reduction) without ammonia slip. However, it is still a developing technology for cement industry and experience is limited. Optimum temperature window for SCR is 350 – 400°C. Two main configurations are proposed – high dust design at preheater exit, requiring frequent cleaning of catalyst and resulting in reduced catalyst lifetime and a low dust design after the waste gas de-dusting requiring reheating of the gases to the temperature window.

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ENVIRONMENT 6 /20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 5 – ENVIRONMENT

2.

SO2

2.1 SO2 from combustion See also chapter Volatile in section pyroprocessing

•

1% sulphur in heavy fuel oil yields 700 ppm SO2 in the dry stoichiometric products of combustion.

2.2 SO2 from raw material A large part of the S content in raw material (sulphates and sulphides) forms SO2 in the upper stages of the preheater and is the main source of stack emissions of SO2 for a preheater / precalciner kiln system. The ability of different process to trap the SO2 is described in the following table: 2-

Online operation of raw mill

Trapping by process

Low

-

Medium

High

Low

High

Medium

Medium

Medium

-

Medium

Low

High

High

High

Kiln type

Process Mastery

Long wet

High

Long dry LEPOL Pre-heater/PreCalciner

S /total SO Mastery

3

A special case is the kiln line equipped with a Chlorine by-pass: the amount of SO2 (in some cases up to 10000ppm) in the by-passed stream can require the addition of some form of SO2 trapping equipment.

2.3 Best Available Control Technologies (BACT) for SO2 emissions (see Cembureau BAT reference document 2000/03) Max. SO2 [mg/Nm³] (10%O2, dry)

SO2 reduction [%]

CAPEX (M€)

Kiln systems applicability

Slaked lime – Ca(OH)2

< 1200

< 60 - 80

0.2 – 0.3

[1]

Slaked lime(slurry) Ca(OH)2 [2]

?

~90

-

Dry

Micromist and others [3] None in operation in cement industry

Circulating fluidized bed Absorber (CFBA)

Wet Scrubber

> 1200 (1500)

<90

~11

Dry

> 1200

75 - ~95

10 – 14

All

> 1200

~95

15

Dry

Activated carbon

Comments

Adsorbs other pollutants from gases

Efficiencies are given for optimum process conditions and cannot be guaranteed for all installations. [1] Dry addition to kiln feed or gas flow after preheater. [2] Slurry addition in conditioning tower, with special solution of “Micromist/ENVIROCARE”. [3] Limited practical experiences in Lafarge and reported unreliable operation (blockage and wear of nozzles). Reported high efficiencies only achieved for a very short time.

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ENVIRONMENT 7 /20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 5 – ENVIRONMENT

Wet scrubber and slaked lime addition are the only ones believed applicable and reliable. NB: there is an draft updated version of BAT (chapters 19, 20) published in 2009, less exhaustive than the previous one, that only refers to absorbent addition and wet scrubber; it also mentions an optimisation of raw milling process (for dry lines) to reduce SO2.

⇒ See Technical Agenda study Gas Scrubber for more details.

3.

Dust

3.1 ESP a) Collection efficiency

•

Gas velocity impacts treatment time and power density (range from 0.6 – 1.5 m/s).

•

Specific collecting area (SCA) in ranges from 60 - 180 m2/Am3/s

•

Migration velocity W (Lafarge NA cement kilns): 30 to 110 cm/s.

•

For a four field ESP with 80% collection efficiency, you will get an overall efficiency of 99.8%. Cumulative Entering Collected Collection Field # (kg) (kg) Efficiency 1 100.0 80.0 80.0 %

•

2

20.0

16.0

96.0 %

3

4.0

3.2

99.2 %

4

0.8

0.6

99.8 %

Modified Deutsch Equation: Efficiency= 1 – (exp – {(A/Q)*W}0.5), where

Q is the gas flow through precipitator, A is the Collection area and SCA (A/Q) is usually calculated to reach the efficiency problem to compute the migration velocity W, 0.5 is an empirical factor. Range of migration velocity (cm/s)

Range of SCA m2/(m3/s)

Wet Kilns

30 – 80

60 - 110

Long Dry Kilns

30 – 60

80 - 180

PH/PC Kilns

45 – 110

65 - 115

Process

Data for ESPs on PC kilns with 400 mm plate spacing and dust emission < 50 mg/Nm3: SCA m2/(m3/s) Main ESP – Direct Operation

70 - 90

Main ESP – Compound Operation

50 – 70

Cooler Exhaust

90 - 120

•

Operating voltage: 30 to 70 kV (in some cases up to 100kV), depending on design factors.

•

Operating current density: 5 to 50 mA/ m2.

•

Dust layer thickness: 0.75 to 1.5cm.

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ENVIRONMENT 8 /20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 5 – ENVIRONMENT

b) Load and particle size Higher voltage gives increased collection efficiency. Usually, the first field will collect the biggest particles and consequently, the finest will be found in the last field. Finer particles are more difficult to capture as shown in the following typical curve: Efficiency % 99.99

99.8

98

90 0.1

1

.

10

50

Particle Size µm

Volatile compounds such as salts of alkali metals and chlorine have a tendency to be attached to the finer dust. Hence separation of dust from the outlet field(s) can be an effective way of bleeding volatile compounds from the process.

c) Gas moisture impact

•

Gas moisture controls the ability to maintain power input.

•

Power increases with moisture at elevated temperatures up to an optimum one.

•

Moisture allows conductance of electrons through dust layer allowing surface voltage to decrease (i.e., higher effective kV) and suppresses space charge effects of fine particles (i.e. reduces sparking). Impact of Moisture & Temperature upon Dust Resistivity

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ENVIRONMENT 9 /20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 5 – ENVIRONMENT

•

Volume of moisture required is not constant and changes with temperature, particle size chemistry, loading and ESP design (i.e., site specific)

3.2 Baghouse a) Filter media

•

There are two types of filter media:

ƒ ƒ

•

Woven Felt

Cloth type and weight are selected, based on temperature, moisture (because of hydrolysis) and resistance (acid, alkali, oxidation and abrasion). Mostly used in cement industries are: Generic name type

Trade name type

Max. temp. on continuous op. (ºC)

Application

Lifetime guarantee (years)

Polypropylene

Herculon

125

General

2

Polyester

Dacron

130

General, mills

2

Glass

Fiberglass

260

Kiln, cooler

3

Polytetrafluorethylene (PTFE)

Teflon

250

Kiln, cement

4

Expanded PTFE

Rastex, Gore-tex

250

Kiln

3–4

Expanded PTFE/Glass

Superflex

250

Kiln

5–6

Aromatic Aramid

Nomex

190

Kiln, cooler

2–3

Polymide

P 84

240

Kiln

2–3

b) Air/Cloth (A/C) ratio (or filtration velocity) Recommended Net A/C m3/s/m2/min

Pressure drop ΔP

Configuration Styles

De-dusting

Mills

Kiln

Coolers

mm Hg

Shaker type

0.6 – 0.8

0.6

–

–

7.5 – 11

Reverse air

0.6 – 0.8 1.2 – 1.8

0.6

0.45 – 0.55

0.5 – 0.6

1.2

0.9 – 1.1

1.0 – 1.3

7.5 – 11 9 – 19

Pulse-jet

c) Bag length

•

For an optimised cleaning effect and longer bag lifetime, the maximum acceptable bag length for a high pressure system is 4m and 7m for the low pressure ones.

• d) Cleaning of Pulse-jet Filters

•

Cleaning can be either online or offline, however, online cleaning is generally preferred due to a lower capital cost. Also online cleaning will lead to more consisted dust flow from the filter, compared to the offline mode

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ENVIRONMENT 10 /20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 5 – ENVIRONMENT

•

Filter designs are available with high pressure (6.5 bar) or low pressure (2.5 bar) cleaning. The advantage of the latter is the increase in bag lifetime to 4-6 years compared with 3-4 years with the high pressure design. Longer bags can also be used with the low pressure design.

3.3 Hybrid filters •

There is a mix -solution for process filters: those that are formed by an electrostatic field in the first part and a bags section in the second.

•

This is a common solution when upgrading a ESP (higher line capacity, adaptation to new regulations, etc.) that can save money (assuming good conditions for casing, electrical part and dust evacuation, the cost of a hybrid filter in an existing ESP casing can be less expensive than a new filter).

•

This solution guarantees the emissions in case of a short-time electrical part malfunctioning while reducing the total pressure loss, air consumption, and increasing the lifetime of bags. A separation of CKD from different uses is also possible.

3.4 Gas Conditioning & Cooling •

In older plants using electrostatic precipitators for the kiln, gas conditioning towers (GCTs) were fitted for gas conditioning to ensure efficient dust collection

•

Modern plants using bag filters are normally fitted with downcomer sprays to reduce gas temperature to a temperature that can be safely handled by the filter bags, normally 200 – 220°C.

•

GCT’s and duct cooling are benchmarked using evaporation rate:

Evaporation _ Rate(kg / hr / m 3 ) =

waterflow(kg / hr ) Effective _ tower _ volume(m 3 )

The effective tower (or duct) volume is defined as the volume available in the straight vertical part starting from the spray entry level.

•

Typical GCT proportions: Length (effective) to Diameter ratio 3 to 4

Spillback systems:

ƒ

High pressure (40 Bar) pumps provided atomization at the nozzles, with flow control fitted on a water return line.

ƒ

Relatively large droplet size 380 – 450 µm : low evaporation rates 15 – 18 kg/hr water / m3 tower volume

ƒ

Variability of droplet size with flow often meant difficult transitions switching from raw mill on to raw mill off condition and vice versa.

ƒ

Difficulty to maintain 150°C outlet temperature

•

Air Atomised systems:

ƒ

Improved atomization with compressed air overcame most of the problems with spillback systems

ƒ

Smaller droplet size 125 – 250 µm depending upon the nozzle design and quantity of compressed air used.

ƒ ƒ

Potential to uprate existing plants and still maintain ESP performance

ƒ

Increase in power consumption due to compressed air 1 – 2 kWh/t clinker

Possibility to use air atomised nozzles for gas cooling in the downcomer (assuming a straight vertical duct) to 200°C when using a bag filter for main dust collector, i.e. no need for a GCT to be installed

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ENVIRONMENT 11 /20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 5 – ENVIRONMENT

ƒ

•

4.

Typical design evaporation rates are up to 30 kg/hr/m3 for GCT’s and up to 50 kg/hr/m3 for cooling in the downcomer. However, “wet bottoms” have been experienced when operating near these upper values.

Multi-Nozzle Lances:

ƒ

Recognising the negative impact upon power consumption, one supplier, Lechler, has developed Multi-Nozzle lances as a solution to improve old spillback systems without having to go to an Air Atomised system.

ƒ ƒ

The design provides smaller droplet sizes than older spillback systems at around 350 µm Operating evaporation rates with these nozzles have been reported up to 24 kg/hr/m3 maximum from installations in Lafarge.

Mercury

4.1 Hg Generalities •

Mercury enters the kiln system with the raw materials and fuels.

•

Raw materials contribute the majority (60-95%) of Hg input into the cement manufacturing process.

•

While raw materials typically have lower mercury concentrations than coal, raw material contribution is larger due to greater mass flow. Limestone influence is the greatest. The range for Limestone is from 0.004 ppm up to 0.81 ppm. High levels have been seen in the layer in contact with clay and shale.

• Variability of mercury concentrations in raw materials is significant maximum ppb

minimum ppb

A verage ppb

100000 10000 1000 100 10 1

Mercury Concentrations in Kiln Feed Materials (Lafarge data 2005-2008).

•

Significant contribution to total mercury has been noted for plants with elevated mercury content in fly ash due to mercury capture in power plants.

•

Hg is highly concentrated in the CKD. The range for CKD is from 0.06ppm up to 40ppm.

•

Hg concentration in the clinker is very low. Hg removal by clinker is negligible.

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ENVIRONMENT 12 /20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 5 – ENVIRONMENT

4.2 Fate of Mercury in the Cement Process •

The mercury vaporizes from the raw material at temperatures between 200°C and 700°C, while mercury in the fuel vaporizes in the flame.

•

The mercury is adsorbed by the solids in the cold end of the kiln, which are captured in the ESP or bag-house.

•

The mercury captured by the ESP or bag-house can be recycled to the pyro-process with the dust. If so, a recirculation loop is established that builds up the mercury levels in the gas and entrained solids until a steady state is established.

•

If the ESP or Fabric Filter temperature is reduced or if kiln gas is passed through the raw mill (when the mill is on line), the mercury emissions in the stack will be reduced due to the higher absorption by the solids. As the solids are recycled to the kiln, the levels of emissions will gradually return to the original values, in the absence of dust removal. However, if dust is removed, the amount of mercury removed with the dust will increase with decreases of ESP or bag-house temperature, so that the net emissions of mercury will be reduced.

4.3 Mercury Abatement Methods a) Primary Measures

•

The primary measures to stop an Hg enrichment cycle must be applied individually or by combination:

⇒ A reduction of the Hg inputs by selecting raw materials and/or fuels with a low Hg content. ⇒ CKD removal, which is the most efficient factor, added to the cement milling stage. ⇒ Hg removal can be improved by a temperature reduction at the inlet of the de-dusting system via an improved Hg trapping on the particles (raw meal, CKD, reagent …).

•

These measures are detailed in the TA Mercury Fate & Control.

b) Secondary Measures

•

Secondary Abatement Measures are proposed in the TA Mercury Fate & Control.

4.4 Regulation •

The regulations are changing with moves to lower emissions of mercury, therefore up to date national regulations need to be consulted.

•

As an example national regulations in European countries range from 30 – 200 µg/Nm3 (dry gas 10% Oxygen, 101.325 kPa and 273 K) for half hourly averages. (Jan 2010).

5.

Dioxins & Furans

5.1 Dioxins & Furans Formation PCDD/Fs can derive from volatile organics in the raw meal and Cl-donors from fuel or raw mix.

•

Organics partially combust hence producing benzene-type compounds or precursors (most likely precursors in cement kilns are: polychlorophenols, polychlorobenzene, phenol, benzene, dibenzofuran).

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•

Precursors react in:

ƒ ƒ

Gaseous phase (mainly 400-700°C): combination of 2 benzene compounds to form PCDD/Fs, Heterogeneous phase i.e. on dust surface (mainly 300-500°C) where they react with Cl2 and HCl + O2 with a metal catalyst (eg: Cu, Fe, Ni, Al, Zn) to form PCDD/Fs.

5.2 Influencing factors of stack PCDD/Fs levels in cement kilns The formation of PCDD/Fs needs several factors at the right level (Temp.; residence time; Cl; precursors; catalyst) otherwise the formation of PCDD/Fs is not possible. Most of the time emissions levels of most of the cement kilns are extremely low. The main factors influencing PCDD/Fs are:

•

Temperature: 400°C is the optimum temperature for PCDD/Fs formation by catalysis on dust. No formation below 180-220°C.

•

Residence time: positive correlation if within temp. window / kiln type (long or short, with gas quenching or not at filter inlet).

•

Presence of catalyst: Cu, Fe, Ni, Al, Zn.

•

Presence of Cl (but no correlation Cl/HCl vs PCDD/Fs)

•

Presence of hydrocarbons from raw materials (but no correlation THCs vs PCDD/Fs)

•

Rate of adsorption desorption on dust: gases through raw mill on or not, bypass or not, baghouse – filter cake acts as adsorbent – or ESP, accumulation of dust in the ducts.

•

SO2 emissions: SO2 react with Cu Æ inhibits the catalyst reaction.

5.3 Primary measures and process optimization to reduce PCDD/Fs By experience, the 6 first primary measures have shown to be sufficient to operate below the emissions limits.

•

Continuous and regular supply of fuels and alternative fuels.

•

Pre-treatment / preparation of waste (waste specific) with the objective to provide a more homogeneous feed and more stable combustion conditions.

•

Feeding of alternative fuels through the main burner or the secondary burner at precalciner-preheater kilns at temperature > 900°C.

•

No alternative material feed as part of raw-mix if it includes organics.

•

Stabilisation of process parameters.

•

No alternative fuels feed during start-up and shut-down.

•

Check the rates of adsorption desorption on dust: gases through raw mill on or not, bypass or not, baghouse – filter cake acts as adsorbent – or ESP, accumulation of dust in the ducts.

•

Check the presence of catalyst.

•

Compare SO2 emissions from the past with present situation. SO2 react with Cu Æ inhibits the catalyst reaction.

•

Quick cooling of kiln and by-pass exhaust gases lower than 200°C – target 180°C.

•

Reduce the retention time of the exit gas in the temperature window of 450°C-200°C at least below 5-10 seconds.

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5.4 Regulations References

EU reference

US reference

Temp. : 0°C

Temp. : 20°C

Pressure : 101,3 kPa

Pressure : 101,3 kPa

O2%vol : 10%

O2%vol : 7%

Limits

Basis : dry EU regulation

0.1 ng TEQ/Nm

Basis : dry 3

0.119 ng TEQ/Nm3

US Regulation (EPA) PMCD* inlet ≥ 204°C

0.169 ng TEQ/Nm3

0.2 ng TEQ/Nm

3

PMCD* inlet < 204°C

0.337 ng TEQ/Nm3

0.4 ng TEQ/Nm

3

* Particulate matter control Device Table from TA DIOXINS & FURANS STUDY - May2004 - version n°1

Regulations expressed as TEQ – Toxic Equivalent Additional information is available in the Technical Agenda DIOXINS & FURANS STUDY – May 2004 – version 1.

6.

Carbon Dioxide

•

The cement industry contributes around 5% of global industrial CO2 emissions and is therefore considered as a major emitter

•

Direct sources of CO2 emissions are the carbonates in the raw feed and from the combustion of fuels. Typical direct emission for a modern preheater/precalciner plant are 850 – 900 kg CO2/t clinker, with around 60% from the calcination of raw materials and the rest from fuel combustion.

•

Indirect emissions are from electric power consumed by the plant. Our main concern is to reduce power consumption. Indirect emissions per MWh vary widely dependant upon the method of electricity production.

•

Main short term options for reduction of direct emissions:

ƒ ƒ ƒ ƒ

•

Increased use of additives in cement to reduce clinker usage Improve fuel consumption of process Increased use of biomass fuels, considered as carbon neutral Use of fuels with lower CO2 intensity (e.g petcoke 95 kg CO2/GJ)

Potential options for the future

ƒ ƒ ƒ

New clinkers / cements requiring less calcium carbonates in raw materials More energy efficient processes CO2 capture and storage

© Copyright 1990 - 2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

ENVIRONMENT 15 /20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 5 – ENVIRONMENT

7.

Others

7.1 Molar ratio calculation (DeNox Example) This part explains how to calculate the molar ratio for a DeNOx system using ammonia solution at 25% of NH3 in mass. The same principle can be used for another component (HCl; SO2…) and another reagent.

•

These definitions have been addressed in the TA Study on NOx reduction techniques – Appendix 14 – page 18.

ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ ƒ

Stack gasflow: 200 000 Nm3/h dry at 10% O2.

ƒ ƒ

Actual NH3 injected: 453.7 x 25/100 = 113.41 kg/hr

ƒ ƒ ƒ ƒ

SCNR Process Efficiency:

ƒ ƒ

Initial NOx (eqNO2 ) emission, without reagent: 1 500 mg/Nm3 dry at 10% O2. NOx flow: 200 000 x (1500 / 1000) = 300 000 g/hr. NOx molar rate : 300 000 / 45.9995 = 6522 mole/hr. Final NOx (eqNO2 ) emission, with reagent

: 500 mg/Nm3 dry at 10% O2.

NOx flow: 200 000 x (500 / 1000) = 100 000 g/hr. NOx molar rate: 100 000 / 45.9995 = 2174 mole/hr. (45.9995 g/mole for NO2) NOx molar rate reduction: 6522 – 2174 = 4348 mole/hr. SNCR reagent: 500 l/hr (453.7 kg/hr) of ammonia solution of 25% in mass of NH3, with a density of 0.9073 kg/litre at 20°C. NH3 molar rate : (113.41 x 1000) / 17.0306 = 6660 mole/hr

Net Molar Ratio: NH3 molar rate / NOx molar rate reduction = 6660 / 4348 = 1.53. NOx reduction rate : NOx molar rate reduction / Initial NOx molar rate = 4348 / 6522 = 66.7% The specific consumption of 25%NH3 solution kg / kg NOx reduced is: 453.7 kg/hr / (200,000 g/hr NOx reduced / 1000) = 2.27 Gross Molar Ratio is: NH3 molar rate / Initial NOx molar rate = 6660 / 6522 = 1.02 NH3 yield = NOx molar rate reduction /nb mole NH3injected = 0.65.

7.2 Correction to Standard Oxygen Conditions How to transform a process measurement to references conditions?

•

Measurement:

ƒ ƒ

•

450ppm NO 8%O2

If reference conditions are 10%O2

⎛ 0.21 − [O2 ]reference ⎞ ⎟ × [NO ]measured ⎟ ⎝ 0.21 − [O2 ]measured ⎠

ƒ

[NO]reference = ⎜⎜

ƒ

[NO]reference = ⎛⎜ 0.21 − 0.10 ⎞⎟ × 450 = 519 ppm ⎝ 0.21 − 0.08 ⎠

© Copyright 1990 - 2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

ENVIRONMENT 16 /20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 5 – ENVIRONMENT

7.3 Continuous Emission Monitoring (CEMS) •

CEMS are required by most national regulations often with online reporting direct to the authorities.

•

In addition to dust emission measurement, the minimum gases to be measured (to be checked with local regulations) are O2, NOx, SO2, CO and TOC (Total Organic Carbons).

•

Use of alternative fuels will increase the requirement for measurement of other gases, both continuous and periodic.

•

Also, due to local regulations, the CEMS must have a proper maintenance as their reliability can influence on the process conditions (AF and ARM use).

7.4 Emission Ranges for European Cement Kilns •

For further details and actual values and reference conditions, please contact your TC.

(based on IPPC Feb. 2009)

© Copyright 1990 - 2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

ENVIRONMENT 17 /20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 5 – ENVIRONMENT

7.5 European AF Kiln Emission Limits Parameter

EC-directive 76/2000 (waste inc.at cem. ind.) Up to 100% non-haz & > 40% haz. 2) < 40% haz. Waste 1) waste DA DA

France 03/05/93

GER: New TA-Luft 24.7.02

GER: 17. BImSchV (Draft 17.3.03)

No waste (case no longer exists)

valid end of 2007

< 60% / > 60% waste

DA

NO + NO2

30

10

50+exempt.

50

500/ 800

5)

200/ 400

NH3

-

-

C org CO HCl HF

10+exempt. 10 1

10 50 10 1

50

DA

5)

11)

20 / 10

30 (50)

3)

350

(200) / 200 (50) / 50

50 (350)

1200/1500/1800

4)

500

1000 /400 500/200

500 (800)

20

(30) -

7)

(30) -

40 / 30

-

-

(20) (100) 60 4

(10) (50) 10 1

12) 13)

to be defined, when using SNCR/SCR

10 (120) 10 0.7

14)

av 0,5-8hrs.

av 0,5-8hrs.

av 0,5-8hrs.

0.05 0.05

0.2 1

0.05 0.05

0.05

0.05 0.05

0.5

5

0.5

av 6-8hrs. 2,3,7,8-TCDDEquivalent

HHA

500/1200/1800

av 0,5-8hrs.

Cd + Tl Hg Sb + As + Pb + Cr + Co + Cu + Mn + Ni + V

DA

[mg/Nm³, dry, 10%O2] [mg/Nm³, dry, 11%O2] [mg/Nm³, dry, 10%O2]

[mg/Nm³, dry, 10%O2]

Dust SO2 + SO3

HHA

AUT: Incineration of 6) waste valid 01/03 (new plants) valid 01/06 (exist. Plants)

0.1 [ng/Nm³]

© Copyright 1990 - 2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

-

0.05

0.03 0.5

0.5

av 6-8hrs.

av 6-8hrs.

0.1 [ng/Nm³]

0.1 [ng/Nm³]

ENVIRONMENT 18 /20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 5 – ENVIRONMENT

8.

References

8.1 Lafarge Documents •

Technical Agenda Study NOx

•

Technical Agenda Study Gas Scrubber

•

Priority Study Bag Filters

•

TA Study Dioxins and Furans

•

TA Study Mercury Fate & Control

•

TA Study On Line Gas Analyser

8.2 External Documents •

IPPC BREF – Dec 2001

•

IPPC Draft Reference Document on BAT – May 2009

© Copyright 1990 - 2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

ENVIRONMENT 19 /20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 5 – ENVIRONMENT

My notes:

© Copyright 1990 - 2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

ENVIRONMENT 20 /20 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 06 – FLUID FLOW

6. Fluid Flow

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

FLUID FLOW 1/14 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 06 – FLUID FLOW

Table of Contents 1.

General Formulas - Definition..................................................... 3 1.1 1.2

2.

Pitot Measurement....................................................................... 6 2.1 2.2 2.3

3.

Fan Power / Efficiency ............................................................................... 9 Fan Laws.................................................................................................... 9 Comparison of Efficiency of Different Fan Control Methods.................... 11

Others ......................................................................................... 11 4.1 4.2

5.

Formula ...................................................................................................... 6 Density Correction ..................................................................................... 6 Measurement Locations............................................................................. 7

Fans .............................................................................................. 9 3.1 3.2 3.3

4.

Basics......................................................................................................... 3 Piping Pressure Losses ............................................................................. 3

Airflow Measurement by Venturi .............................................................. 11 Estimating False Air ................................................................................. 12

Reference Documents ............................................................... 13 5.1 5.2

Cement Portal .......................................................................................... 13 International Standards............................................................................ 13

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

FLUID FLOW 2/14 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 06 – FLUID FLOW

1. General Formulas - Definition 1.1

Basics

Avogadro Law •

Equal volumes of different gases at the same pressure and temperature contain the same number of molecules.

•

Avogadro’s number N: The number of molecules in one gram-mole of a gas, N = 6.022 x 1023.

Ideal Gas Law

- P Absolute pressure

( )

PV = nRT

- V Volume m

(Pa )

- T Absolute Temperature (K ) - n Number of moles (gmole)

3

- R Universal Gas Constant =8.31434 J/gmole.ºK •

1 gmole of ideal gas at normal conditions (0ºC, 101325 Pa) occupies a volume of 22.414 litres.

Bernoulli •

For a steady, one-dimensional incompressible flow without losses:

P + ρgz + ρ

v2 = Cst 2

Where: - P static pressure in N/m2 (=Pa) ρ density in kg/m3 g acceleration due gravity 9.81m/s2 z: elevation in m v fluid velocity in m/s

-

1.2

Piping Pressure Losses

a. Formulae Pressure Drop Formula •

Circular pipe, constant area. The pressure drop is:

ΔP = f

L v2 ρ D 2

Where: -

ΔP f D

ρ v L

Pressure drop (Pa) Friction factor (Darcy) Pipe diameter (m) Fluid density (kg/m3) Average fluid velocity (m/s) Pipe length (m)

Friction Factor

f =

Laminar flow (Re < 2000)

64 Re

- Re Reynolds Number Transition Zone (Re > 3000) - f dependant upon Re and absolute roughness e

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

⎛e 2.51 = −2 log⎜⎜ D + ⎜ 3.7 Re f f ⎝

1 D

⎞ ⎟ ⎟⎟ ⎠

FLUID FLOW 3/14 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 06 – FLUID FLOW

f =

Turbulent Zone - Re dependant upon absolute roughness - f independent of Re

Reynolds Number (Dimensionless)

Re =

1 ⎞ ⎛ ⎜ 2 log 3.7 ⎟ ⎜⎜ e ⎟⎟ D⎠ ⎝

2

where: - k kinematic viscosity (m2/s)

v ∗ D ρ *v* D = k μ

-

-

Average fluid velocity (m/s) Diameter of the pipe (m) (for a rectangular duct equivalent diameter = 2* a* b ) a+b μ the absolute viscosity (Pa.s)

v D

Roughness • Roughness (e): the mean distance between high and low points of the surface.

•

Typical values e (m)

•

Commercial steel

0.00005

•

Drawn tubing

0.0000015

•

Concrete pipe

0.0009

Example Pressure Drop Calculation

Calculate the pressure drop of 60,000 m3/hr of air (20° C and 101325 Pa) flowing through a horizontal steel pipe of 100m long and 1 m internal diameter. The gas density is 1.2 kg/m3 and viscosity is 1.72 x 10 -5 Pa.s

(

)=

60000 = 21.22 Π * 12 4

•

Gas velocity v m.s

−1

•

Reynolds Number

Re =

•

Absolute roughness e

•

Look up Darcy friction factor from Moody chart (see below) or solve

D

1.2 * 1 * 21.22 = 1.486 * 10 6 −5 1.72 *10 =

0.00005 = 0.00005 1

⎛e 2.51 = −2 log⎜⎜ D + ⎜ 3.7 Re f f ⎝

⎞ ⎟ by iterative calculation f = 0.0121 ⎟⎟ ⎠ 100 1.2 * 21.22 2 Calculate Pressure Loss ΔP ( Pa ) = 0.0121 * * = 329 1 2 1

•

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

FLUID FLOW 4/14 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 06 – FLUID FLOW

Average velocity in industrial design Cold air (higher for larger size) Hot air Dusty Gases Natural Gas Water general services Viscous oil Slurries

10 to 15 m/s 20 to 25 m/s 25 to 30 m/s 10 (20 mm pipe) to 30 m/s (100mm pipe) 1 to 3 m/s 0.3 to 0.6 on pump suction and 1 to 2 m/s on discharge 1.5 to 2 m/s for 20 to 200 micron particles

b. Pressure Losses for Fittings etc Restriction, elbow... Length of straight pipe (of same size) that would produce the same pressure drop as the fitting, elbow… expressed in L/D Nominal pipe size (D mm) 90 elbow r/D=8

12 1.24

25 2.10

50 4.13

75 10.1

Nominal pipe size (D mm) 90 elbow r/D=1 Mitred 45 elbow Pipe exit Pipe entrance Enlargement 0.5 Contraction 0.5

25 2.1 1.4 3.8 3.04 2.13 1.33

150 10.1 7.58 33.7 27 18.9 11.8

350 22.5 16.9 86.5 69.2 48.5 30.3

750 49 36.7 213 170 119 74.5

r= pipe radius, D=inside pipe diameter Examples of other Pressure Loss Relationships • Pressure loss through filter bag: Δp = hv , v is the velocity

•

Pressure loss through a grain bin: Δp = hv

1.5

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

FLUID FLOW 5/14 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 06 – FLUID FLOW

2. Pitot Measurement 2.1

V =k

2.2

Formula 2.Δp

ρ

where: V = Gas velocity in m/s - k = Pitot tube correction factor (eg. “S” tube = 0.85) Δp = Average velocity (dynamic) pressure in Pa ρ = density in kg/m3 -

Density Correction

Temperature and Pressure

•

ρ = ρo .

(Pb + Ps ) 273.15 . o 273.15 + T ( C ) ) 101325

-

Pb = Barometric pressure (Pa) Ps = Static pressure (Pa ) ro= density (kg/m3 )

Water and Chemistry: example

•

Gas: CO 2 = 20% , H 2 O = 10% , O2 = 15% , N 2 = 100 − (20 + 10 + 15 ) = 55%

•

ρ =⎜

⎞ ⎞ ⎛ 28 ⎞ ⎛ 32 ⎞ ⎛ 18 ⎛ 44 x 0.2 ⎟ + ⎜ x 0.55 ⎟ + ⎜ x 0.15 ⎟ + ⎜ x 0.55 ⎟ = 1.375kg.Nm −3 ⎠ ⎠ ⎝ 22.4 ⎠ ⎝ 22.4 ⎠ ⎝ 22.4 ⎝ 22.4 Warning: Dry or Wet Basis? Be careful to take account of the basis for the measurement of gas composition, usually it is measured on a dry basis

Dust

•

The pitot formula is correct only for clean gas, so whenever possible measure airflow in clean in a gas. In cases where there is no option but to measure a dusty gas flow an approximation can be made by adding the dust loading to the gas density:

ρ = ρ gas + dust concentration (kg/m3)

ρ =1.375+0.07=1.445

•

In the previous example with a dust concentration of 70 g/Nm3, then (assuming dust does not take up room in the gas stream).

kg/m3

•

In case of dusty gas, an Straucheib (S type) tube is used instead of L-Tube (see coefficient correction below).

Standard Pressure Conditions

•

•

Standard day sea level pressure : - 760mm Hg 29.92 in. Hg 10332 mm WG 2 - 101325 Pa 14.696 psi (lb/in ) 406.8 in. WG Normal Conditions: Standard sea level pressure 0oC.

Effect of Elevation on Atmospheric Pressure

•

(

P ( Pa) = P0 1 − 2.2558 * 10 −5 * h

)

5.255

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

where: h = elevation (m)

FLUID FLOW 6/14 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 06 – FLUID FLOW

Averaging the dynamic pressure:

•

⎛ ∑ ( pv ) ⎞ ⎟ ⎜ Δp = ⎜ N ⎟ N ⎟ ⎜ ⎠ ⎝

2

where p v = traverse readings

Pitot Correction coefficient

•

2.3

If any, the corrective coefficient for the pitot tube (for instance k=0.84) is applied directly on the velocity as calculated.

Measurement Locations

The idea is to have the same surface area for each measurement. Methods include Centroid and LogTchebychef (Centroid method) Total traverse points per diameter # point #1 #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 #12 #13 #14 #15 #16 #17 #18 #19 #20 #21 #22

4 .062 .250 .750 .938

6 .044 .147 .295 .705 .853 .956

8 .033 .105 .194 .323 .677 .806 .895 .967

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

10 .025 .082 .146 .226 .342 .658 .774 .854 .918 .975

12 .021 .067 .118 .177 .250 .355 .645 .750 .823 .882 .933 .979

14 .018 .057 .099 .146 .201 .269 .366 .634 .731 .799 .854 .901 .943 .982

20 .013 .039 .067 .097 .129 .165 .204 .250 .306 .388 .612 .694 .750 .796 .835 .871 .903 .933 .961 .987

22 .011 .035 .060 .087 .116 .146 .180 .218 .261 .315 .393 .607 .685 .739 .782 .820 .854 .884 .913 .940 .965 .989

FLUID FLOW 7/14 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 06 – FLUID FLOW

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

FLUID FLOW 8/14 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 06 – FLUID FLOW

3. Fans 3.1 •

Fan Power / Efficiency Useful Power (Theoretical Air Power):

20

Wu (Watts) = Pt * Q

18

-

•

• •

P: Total fan pressure (Pa) Q: Volume flow (m3/s)

12

Usually the supplier gives fan shaft power vs flow

6

Fan total efficiency at any point is given by :

2

Wu Pt * Q η = = t Ws Ws

0

120 100

Wu

14

Difference between the useful power and the fan shaft power is due to skin friction, fluid turbulence….

‘V’ Belt drive Flat Belt

Power

16

80

10

Pressure Efficiency

8

60 40

4 20

0

5000

10000

15000

20000

25000

30000

0 35000

Flow Rate Q

• •

Drive Efficiency

• •

140

Reducer Direct Drive

95 - 96% 99.5%

90 – 95% 99%

a. Typical Efficiencies for Different Blade Types (Test Conditions supplier figures) • •

Straight radial: 60-75% efficiency (fan shaft) Backward inclined : 75 – 80%

• •

Backward curved radial: 78 - 85 % (for dusty gas). Airfoil: 84 - 91% (clean gas).

b. Efficiency Losses due to Faults • • •

3.2

Cone condition: 3-4% Missing Inlet duct flow guide: 2-5%. Build up on impellor: 4-6 %

Fan Laws

a. Fan Law Summary Change in Parameter Density

Total Effect All Changes

ρ

Speed N

Width L*

Diameter D*

Flow Q

0

N

L

D3

N. L. D3

Pressure P

ρ

N2

0

D2

Power W

ρ

N3

L

D5

ρ .N2. D2 ρ .N3. L. D5

Impact on Fan

*A change in dimensions applies to fans of identical geometry; although these two laws can be used to give approximate effects for small changes in size e.g. fan impellor tipping.

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

FLUID FLOW 9/14 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 06 – FLUID FLOW

b. Gas Density Influence (Fans are constant volume machines) • Pressure: proportional to gas density

P1 ρ1 = P0 ρ 0

•

•

18

Power: proportional to gas density

W1 ρ1 = W0 ρ 0

100

12 10

80

8

60

6

System curve : proportional to gas density

H 1 ρ1 = H 0 ρ0

40

4

20

2 0 0

5000

10000

15000

20000

25000

30000

0 35000

Flow Rate Q

•

25

density) Volume: directly proportional to fan speed

Q1 N 1 = Q0 N 0

250

200

20 150

Pressure: proportional to square of speed 2 P1 ⎛⎜ N1 ⎞ ⎟ = P0 ⎜ N 0 ⎟⎠ ⎝

Power: proportional to cube of speed

W1 ⎛⎜ N 1 = W0 ⎜ N 0 ⎝

120

14

30

•

140

16

c. Fan Speed Influence (same circuit & gas

•

160

20

⎞ ⎟⎟ ⎠

3

15 100 10 50

5

0 0

5000

10000

15000

20000

25000

30000

35000

0 40000

Flow Rate Q

Warning:Common Traps with Fan Curve Conventions A) Be sure to know the pressure basis used for drawing the fan curve, suppliers have 3 main conventions;1) Total pressure; 2) Fan static pressure ; 3) Static pressure rise. B) Usually the fan curve refers to inlet volume but some suppliers use average volume between inlet and outlet of the fan. C) For dusty gases suppliers usually adjust the power curve by adjusting the gas density, some suppliers use 100% of the dust content whlist others use 50% of the dust content. This will impact the D) You can also find curves drawn with specific energy and fan efficiency against fan flow, where you will need to calculate the power and pressure curves.

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

FLUID FLOW 10/14 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 06 – FLUID FLOW

3.3

Comparison of Efficiency of Different Fan Control Methods 100 90 80

% Power

70

Inle t d a m p e r

O utle t damper

60

Inle t va ne s

50 40 30

V a ria b le sp e e d

20 10 0 0

10

20

30

40

50

60

70

80

90

100

% F lo w

Louvre Damper Flow Control

Radial Vane Damper Flow Control

120 100

20% open 40% open

80

60% open

60

80% open

40

Wide open 20

100

100

90

90

80

80

70

70

60

60

50

50

40

40

30

30

20

20

10 0 0

10000

20000

30000

40000

50000

60000

70000

80000

25% open

0 0

10000

20000

30000

40000

50%

50000

75% 100%

60000

70000

10

0 80000

F low

Flow

Louvre dampers modify system resistance to Radial vane dampers modify the fan curve to adjust gas flow adjust gas flow

4. Others 4.1

Airflow Measurement by Venturi 1

2

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FLUID FLOW 11/14 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 06 – FLUID FLOW

Q = C v . A1 .

4.2

2.( P1 − P2 ) ⎛⎛ A ⎞2 ⎞ ρ .⎜ ⎜⎜ 1 ⎟⎟ − 1⎟ ⎜ ⎝ A2 ⎠ ⎟ ⎝ ⎠

Where: Q – gasflow m3/s Cv venturi coefficient (usually 0.98) A1 & A2 areas at 1 & 2 m2 P1 & P2 pressures at 1, & 2 Pa R gas density kg/m3

Estimating False Air

Velocity through an opening:

V = 0.6.

2..ΔP

ρ

Where : V – velocity m/s ΔP – pressure drop Pa r – gas density kg/m3

Note: the formula is only approximate since the discharge coefficient 0.6 can vary depending upon the shape of the opening, etc. Example False Air Estimation

Estimate the false air into a kiln inlet seal with an opening of 6mm around the periphery of the kiln, with a diameter of 4.5 m, kiln inlet pressure is -350 Pa.

(

)

4.512 2 − 4.5 2 .π 2.350 V = 0.6. = 14.8m / s : FlowArea = = 0.0849m 2 4 1.15

Flow = 14.8 x 0.0849x 3600 = 4525 m3/hr

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FLUID FLOW 12/14 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 06 – FLUID FLOW

5. Reference Documents 5.1

Cement Portal

How to Procedures How to measure airflow by Pitot tube How to measure static pressure by Pitot tube How to measure gas temperature by thermocouple How to measure moisture of gas by wet bulb temperature How to measure moisture content of gases using silica gel How to measure gas composition by gas analyser How to measure false air How to measure fan efficiency of the main fans How to improve fan efficiency by internal inspection Tools Lafarge Pitot Measurements

5.2

International Standards

ISO 3966 - Measurement of fluid flow in closed conduits — Velocity area method using Pitot static tubes ISO 5167 - Measurement of fluid flow by means of pressure differential devices inserted in circular crosssection conduits running full -- Part 4: Venturi tubes ISO 5801 - Industrial fans -- Performance testing using standardized airways

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FLUID FLOW 13/14 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 06 – FLUID FLOW

My notes:

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FLUID FLOW 14/14 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 7 – PROCESS CONTROL

7. Process Control

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Process Control – Page 1/9 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 7 – PROCESS CONTROL

Table of Contents 1.

2.

3.

Control Loops..............................................................................................3 1.1

Open Loop ...................................................................................................... 3

1.2

Feed Forward Control..................................................................................... 3

1.3

Feed Back Control .......................................................................................... 3

1.4

Cascade Control ............................................................................................. 4

Feed Back Controller, PID ..........................................................................4 2.1

General ........................................................................................................... 4

2.2

Proportional Gain:........................................................................................... 4

2.3

Integral Action (Reset time): ........................................................................... 5

2.4

Derivative Function: ........................................................................................ 5

2.5

PID controller .................................................................................................. 5

Controller Tuning ........................................................................................6 3.1

Tuning General ............................................................................................... 6

3.2

Online Trial and Error Tuning ......................................................................... 6

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Process Control – Page 2/9 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 7 – PROCESS CONTROL

1. 1.1 • •

Control Loops Open Loop Based on experience, the inputs are set to achieve the good target on output. This kind of control does not react towards the perturbations that can happen in the inputs or in the process. Example: Open Loop Control

In a mill open circuit, the quantity of feed to give the good cement fineness.

1.2 • •

Feed Forward Control A measurement of the inputs is made and changes are made on the actuators to obtain the good target of the output. It does not take into account the unmeasured perturbations.

Disturbances

Feed forward controller Manipulative variable

Process

Controlled variable

Examples: Feed Forward Control

Water injection quantity in the first compartment based on the clinker temperature. Gypsum addition based on SO3 in Gypsum and clinker.

1.3 Feed Back Control • A measurement of the variable to be controlled (output) is made and compared with a set point. If a difference exists between the measured and the setpoint value, corrections are made on the inputs to get the correct value.

Disturbances Manipulative variable

Process

Controlled variable

Feedback

Output

controller

setpoint

Examples: Feedback Controllers

Water injection controlling the mill discharge temperature. Feed rate controlling the circulating load. Fan speed controlling cooler fan Airflow Fuel federate controlling precalciner temperature

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Process Control – Page 3/9 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 7 – PROCESS CONTROL

1.4 • •

Cascade Control The primary controller (master) is used to vary the setpoint of the secondary controller (slave) It can be usefully applied with two interacting variables especially when it is required to keep the measured variable of the slave controller within a ertain range

Disturbances Manipulative variable

Output

Process

Secondary Controller

Controlled variable 1

Controlled Variable 2

setpoint

Primary Controller

Example: Cascade Control

Primary: Controlling coal mill inlet temperature setpoint by the mill outlet temperature Secondary : Coal mill hot air damper (and recycle damper) controlling coal mill inlet temperature

2.

Feed Back Controller, PID

2.1

General

Controllers automatically compare the value of the PV to the SP to determine if an error exists. If there is an error, the controller adjusts its output according to the parameters that have been set in the controller. The tuning parameters essentially determine how much correction should be made (proportional), how long should the correction be applied (integral) and the speed at which a correction is should be made (derivative). Controllers are tuned in an effort to match the characteristics of the control equipment to the process so that two goals are achieved: •

The system responds quickly to errors.

•

The system remains stable (PV does not oscillate around the SP).

2.2

Proportional Gain:

Gain of a controller is defined simply as the change in output divided by the change in input.

•

Gain =

Δ output Δ input

The adjustment of the controller output due to proportional action is given by:

Y = Y0 ± K p ( X − S ) Where: Y – New controller output Y0 – Existing controller output KP – Proportional gain

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Process Control – Page 4/9 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 7 – PROCESS CONTROL

X – measured value S – controller setpoint Since the proportional action only responds to a change in error (between setpoint and measured value) then on it’s own it will not return the measured value to setpoint. Note: Proportional Band

Proportional band is another way to represent gain. PB=100/gain.

2.3

Integral Action (Reset time):

The purpose of integral action is to return the PV to SP. This is accomplished by repeating the action of the proportional mode as long as an error exists. With the exception of some electronic controllers, the integral or reset mode is always used with the proportional mode. The setting is made in minutes or seconds. The effect of the integral time on the control output is given by:

Y = Y0 ± 2.4

Kp Ti

∫ ( X − S ) dt

Where Ti – integral action time

Derivative Function:

The purpose of the derivative action (rate action) is to try to anticipate the control action by looking at the time rate of the error change (the derivative).

Y = Y0 + Td

•

dX dt

where Td is the derivative action time (min)

In theory, the derivative action should always improve the system response. But, it is necessary to give a particular attention to this term because there is not perfect derivative action, and if the signal is very noisy, the derivative action amplifies the noise, producing fluctuation in the control.

X

S Derivative action

Yo Proportional action

Resulting action

Y

Integral action Time

2.5

PID controller

The 3 terms together form the overall PID controller:

Y = Y0 ± K p ( X − S ) ±

Kp Ti

∫ ( X − S ) dt ± K p Td

dX dt

Not every process requires a full PID control strategy.

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Process Control – Page 5/9 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 7 – PROCESS CONTROL

PI control is used where no offset can be tolerated, where noise (temporary error readings that do not reflect the true process variable condition) may be present, and where excessive dead time (time after a disturbance before control action takes place) is not a problem. In processes where no offset can be tolerated, no noise is present, and where dead time is an issue, use full PID control.

3.

Controller Tuning

3.1

Tuning General

There are several established techniques for controller tuning, Zeigler Nichols Open Loop, Zeigler Nichols Closed Loop, Internal Model Control. In addition there are online and offline automatic tuning tools that can be used to the optimum control parameters. However, for the moment the most frequently used in our plants is by online trial and error.

3.2 a)

Online Trial and Error Tuning Proportional action: -

Set integral and derivative action at 0 action (maximum Ti , minimum Td ). Set K p at a low value, for example 0.5. (use a typical value for your system if you know already, look at operator actions) Put the controller in auto. With a small change in set point, the controller reaction will be very sluggish. Double the proportional coefficient until the loop becomes oscillatory. After reaching this ultimate gain, set the K p half of the ultimate K p .

Low Gain Example - In the example below, the proportional band is high (gain is low). The loop is very stable, but an error remains between SP and PV.

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CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 7 – PROCESS CONTROL

High Gain Example - In the example, the proportional band is small resulting in high gain, which is causing instability. Notice that the process variable is still not on set point.

b) Integral action: -

With the controller in auto and the proportional band fixed, start to reduce Ti by factor 2, with small changes in set point after each step. Find the value of Ti that makes the system oscillatory, underdamped and set Ti double of that.

High Integral Time (Slow Reset) Example - In this example the loop is stable because the total loop gain is not too high at the loop critical frequency. Notice thatthe process variable does reach set point due to the reset action.

Short Integral Time (Fast Reset) Example - In the example the reset is too fast and the PV is cycling around the SP.

c)

Derivative action: -

Increase the derivative term until the system noise starts to appear on the controller output. Set the Td at THIRD of this maximum value.

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Process Control – Page 7/9 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 7 – PROCESS CONTROL

No and Slow Derivative Rate Examples –

Effect of Fast Rate – Increase of the rate setting increases controller gain much higher. As a result, both the IVP (controller output) and the PV will cycle. Increasing the rate setting will not cause the PV to settle at the SP.

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CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 7 – PROCESS CONTROL

My notes:

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Process Control – Page 9/9 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 8 – REFRACTORIES

8. Refractories

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REFRACTORIES – Page 1/12 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 8 – REFRACTORIES

Table of Contents 1.

Process Impacts on Refractories ..............................................................3

2.

Refractory Classification ............................................................................4

3.

2.1

Alumina Bricks ................................................................................................ 4

2.2

Basic Bricks .................................................................................................... 4

2.3

Monolithics (unshaped products) ................................................................... 6

Kiln Zoning ..................................................................................................6 3.1

Typical Zoning for an AS Precalciner Kiln ...................................................... 6

3.2

Refractory Layout ........................................................................................... 7

4.

Kiln Retaining Ring .....................................................................................7

5.

Installation Methods for Kiln Bricks ..........................................................8 5.1

Bricks for Rotary Kilns .................................................................................... 8

5.2

Brick Installation Methods............................................................................... 8

6.

Refractory Storage ......................................................................................9

7.

Refractory Performance Indicators ...........................................................9

8.

Kiln Heat Up Profiles.................................................................................10

9.

Division Reference Documents ...............................................................10 9.1

How to procedures ....................................................................................... 10

9.2

Tools ............................................................................................................. 11

9.3

Other important documents .......................................................................... 11

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REFRACTORIES – Page 2/12 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 8 – REFRACTORIES

1.

Process Impacts on Refractories

The nature of the clinkering process in rotary kiln necessitates that the kiln lining needs to withstand not only high temperatures, but also to resist destruction by the extremely aggressive environment. Potential Impacts are shown in the schematic below:

Impacts on the Lining Thermal •Flame / impingement •Overheating •Thermal cycling •Thermal Shock Atmosphere •Reducing •Oxidising •Cycling •Volatiles •Dust Kiln Charge •Infiltration of liquid •Condensation Volatiles •Chemical Attack •Abrasion •Chemical Variations •Stability / presence coating

Mechanical •Shell condition •Shell ovality •Kiln alignment •Tyre clearances •Shell thickness •Kiln speed

Lining Stability •Brick Quality •Brick Tolerance •Fitting to shell •Ring tightness •Alignment to shell •Expansion allowance •Retaining ring

•

Refractories are not able to withstand the extremes of all conditions – design is a compromise of properties

•

First approach to a premature failure / wear issue should be to make improvements to the process conditions and equipment to reduce the impact upon the refractories, instead of trying to change the refractory specification

•

Most important property of refractory selection is “performance in service” – hence development of Division Equivalency Chart

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CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 8 – REFRACTORIES

2.

Refractory Classification

2.1

Alumina Bricks

The main components of alumina bricks are alumina (Al2O3) and silica (SiO2). Main raw materials used are bauxite, andalusite (sillimanite group) and fireclay. There are 3 classifications: •

High alumina with alumina content of >45%

•

Firebrick with alumina content <45%

•

Insulating firebrick with > 45% porosity

TYPICAL DATASHEET PROPERTIES OF ALUMINA BRICKS High Alumina

Fireclay

Insulating

Al2O3

60

42

33

Fe2O3

0.9

1.9

1.6

35.5

54

60

2.6

2.2

0.8

13

18

68

1520

1440

1380

1.6

1.4

0.33

SiO2 Density t/m

3

Apparent Porosity % Temp Limit °C Thermal Conductivity 1000°C W/mK

2.2

Basic Bricks •

Main oxides magnesia (MgO) or lime (CaO).

•

Additional raw material or synthetic product e.g spinel to give flexural strength

•

Mainly synthetic materials, except dolomite which occurs naturally

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REFRACTORIES – Page 4/12 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 8 – REFRACTORIES

•

The classification refers to the raw material base or the elasticising system Raw Material Base

o

ƒ

magnesia (MgO)

ƒ

magnesia doloma (MgO CaO)

ƒ

magnesia zirconia (MgO ZrO2)

ƒ

forsterite (MgO SiO2)

Spinel Systems

o

ƒ

magnesia spinel (MgOAl2O3)

ƒ

magnesia hercynite (MgOFe2O3)

ƒ

magnesia galaxite (MgOMn2O3)

ƒ

magnesia chromite (MgOCr2O3).

TYPICAL DATASHEET PROPERTIES OF BASIC BRICKS Magnesia MA Spinel

Magnesia Hercynite

Magnesia Chrome

Dolomite

Dolomite Zircon

CaO

-

-

-

59

58

MgO

87

85

81.5

38

38

Fe2O3

0.5

7.4

8

0.5

0.7

Al2O3

10.5

3

2.2

1

0.5

ZrO2

-

-

-

-

1

-

-

5.8

-

-

Cr2O3 3

Density t/m

2.94

3.05

3.03

2.86

2.83

Apparent Porosity %

15

15

17.5

15

16

Refractoriness under load °C

>1700

>1600

>1600

>1400

>1400

3.0

2.4

2.3

2.6

2.4

Thermal Conductivity 1000°C W/mK

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REFRACTORIES – Page 5/12 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 8 – REFRACTORIES

2.3

Monolithics (unshaped products)

There are various methods to classify monolithics. For detailed information please refer to DIN EN 14021. The following table is one way to classify monolithics.

RC = Regular Cement Concrete MCC = Medium Cement Concrete LCC = Low Cement Concrete ULCC = Ultra Low Cement Concrete NCC = Now Cement Concrete

3. 3.1

Kiln Zoning Typical Zoning for an AS Precalciner Kiln

Outlet zone:

up to 1.2m

Lower Transition Zone (LTZ):

1–2xØ

Burning Zone (BZ):

6-8xØ

Upper Transition Zone (UTZ):

2–4xØ

Safety (Security) Zone (SZ):

2xØ

Calcining Zone (CZ):

up to kiln inlet

(Ø = kiln diameter)

Lower Transition Zone

Burning Zone

Upper Transition Zone

Safety Zone

Calcining Zone

Outlet Zone

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REFRACTORIES – Page 6/12 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 8 – REFRACTORIES

3.2

Refractory Layout

The final refractory layout of the burning line is determined by the stresses (thermal, chemical and mechanical) applied upon the refractory lining at the application area. At the above example of an AS Precalciner kiln system with grate cooler a standard refractory layout could be like: Outlet zone:

75 – 85% Alumina

Lower Transition Zone (LTZ):

magnesia spinel, magnesia doloma

Burning Zone (BZ):

magnesia spinel, magnesia hercynite, magnesia galaxite, magnesia doloma, forsterite

Upper Transition Zone (UTZ):

magnesia spinel, magnesia hercynite, magnesia galaxite

Safety (Security) Zone (SZ):

60 – 75% Alumina

Calcining Zone (CZ):

30 – 50% Alumina

4.

Kiln Retaining Ring

To reduce the lining thrust on the kiln outlet segments a metallic retaining ring is installed at distance of up to 1200mm from the discharge end. Lining thickness Kiln diameter (m) (mm)

Retaining ring (X in mm)

Kiln Diameter D (m)

Number of sections

180

Less than 3.6

60

D<3

8

200

3.6 to 4.2

70

3
12

220

4.2 to 5.2

80

D>5

16

220 or 250 (*)

> 5.2

80 or 100 (*)

(*) to be confirmed The retaining rings are made of the following steel qualities: A 42 CP or W Sc E255 or E 24-2.

Section Length

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REFRACTORIES – Page 7/12 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 8 – REFRACTORIES

5.

Installation Methods for Kiln Bricks

5.1

5.2

Bricks for Rotary Kilns •

A combination of two different tapered brick shapes is used.

•

Brick shapes are standardised according to VDZ, ISO and ASTM standards according to turning circles of whole metres e.g. 2, 3, 5, 6 and 8 metres

•

A combination of two standard brick sizes with a proper mixing ratio allows for lining any kiln diameter.

Brick Installation Methods

a) Bricking Machine The most common and safest method to install kiln bricks is the use of a bricking machine. The lower half of the kiln is bricked first and the bricking machine is used to brick the upper half. Pneumatic jacks in a rig (arch) keep the bricks in place until the ring is closed and self supporting. The kiln does not need to be rotated.

b) Bricking Template A bricking template is similar to the bricking rig but without pneumatic pressure. Wooden wedges are used to keep the bricks in place until the ring is closed and self supporting. The kiln does not need to be rotated. c) Screw Jack Method With the screw jack method the kiln needs to be rotated. The lower half of the kiln is bricked before screw jacks are installed to fix the bricks at 90° and 270°. The kiln is turned 90°. The next screw jack is installed to fix the bricks as before. The kiln is turned another 90° to close the last section.

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REFRACTORIES – Page 8/12 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 8 – REFRACTORIES

d) Glue Method With the glue method the kiln needs to be rotated. Typically a two component epoxy resin is spread in axial direction on the clean kiln shell at a width of about six bricks. In total four to six glue strips are applied per circumference, dependent on the kiln diameter, as the bricking work progresses.

e) Bolt Method With the bolt method the kiln needs to be rotated. A number of nuts are welded on the kiln shell in axial direction. Two lines of bricks are installed in parallel to the nuts. Threaded bolts and U-shaped iron pieces are fixing both brick lines. In total two to four of such stripes are applied per circumference, dependent on the kiln diameter, as the bricking work progresses. As a final step, each fixation is removed and the gap filled with bricks.

6.

7.

Refractory Storage •

Basic bricks and monolithics have a shelf life from 6 to 12 months.

•

Both products are sensitive to water or high level of humidity

•

Monolithics are additionally sensitive to high or freezing ambient temperature.

•

Basic bricks and monolithics should be stored dry and well ventilated.

•

Storage height should not exceed five (5) pallets.

•

Apply first in first out.

Refractory Performance Indicators

NSFRI: Number of Stops For Refractory Incidents <1 Benchmark of specific refractory consumption by kiln system [g refractory/t clinker] Semi Dry

300

Air Separate Precalciner

300

Long Dry

500

Air Through Precalciner

500

Long Wet

800

Suspension Preheater

500

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REFRACTORIES – Page 9/12 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 8 – REFRACTORIES

8.

Kiln Heat Up Profiles

The heating up of refractories must be done slow enough to avoid excessive thermal and mechanical stress in the lining, otherwise serious damage could result. The cooling down of refractories should also be done slowly for the same reasons.

See the procedure “How to warm up / cool down a kiln” on the Cement Portal (Refractory Domain)

9. 9.1

Division Reference Documents How to procedures

• How to select the refractory • How to perform trials • How to receive and store bricks • How to ensure safety for brick demolition and lining works • How to ensure safety for brick cutting • How to ensure safety for castable mixing • How to ensure safety for cyclone lining works • How to align kiln burner • How to align the burner pipe • How to cast low cement castables • How to place anchors for monolithic • How to start the brick work • How to line the kiln (dry method) • How to line the kiln (other tying methods) • How to line the kiln inlet

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REFRACTORIES – Page 10/12 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 8 – REFRACTORIES

• How to install and line the retainer ring • How to cast the nose ring • How to use a shell scanner • How to use the shell cooling fan • How to plan a kiln shut down • How to handle a hot spot • How to assess the refractory condition after a kiln stoppage • How to warm up / cool down the kiln • How to line the cyclones • How to line riser ducts

9.2

Tools

• Division Equivalency chart • Winbrix • Heat losses calculation

9.3

Other important documents

• Brick lining installation golden rules • Coating and lining inspection check list • Brick failure investigation check list

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REFRACTORIES – Page 11/12 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 8 – REFRACTORIES

My notes:

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REFRACTORIES – Page 12/12 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-1 – MATHEMATICS

9-1. Mathematics

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MATHEMATICS - Page 1/8 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-1 – MATHEMATICS

Table of Contents

1. Algebra ............................................................................................... 3 2. Trigonometry...................................................................................... 4 3. Plane Geometry ................................................................................. 5 4. Solid Geometry .................................................................................. 6

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CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-1 – MATHEMATICS

(

a 3 − b3 = (a − b ) a 2 + ab + b 2

1. Algebra a) Exponents am ∗ an = am+n

e) Logarithms log x + log y = log( xy ) x log x − log y = log y

( )( )

(a m )n = a mn (am )∗ (bm ) = (a ∗ b)m am an

=a

( )

x * log y = log y x 1 log n x = * log x n log10 a = 0.4343 In a In a = 2.3026 log10 a

m−n

an

⎛a⎞ =⎜ ⎟ n ⎝b⎠ b

)

n

a1 / k = k a 1 a−n = an

f) Determinants

ax + by + cz = d , ex + fy + gz = h , ix + jy + kz = l

Simultaneous equations:

n

am / n = am

If:

b) Fractions a c a±c ± = b b b a c a∗c ∗ = b d b∗d a c a∗d a d ÷ = = ∗ b d b∗c b c

a

b

c

d

b

c

D = e i

f j

g k

D1 = h l

f j

g k

a d

c

a

b

d

D2 = e

h

g

D1 = e

f

h

i

l

k

i

j

l

The solution is:

c) Radicals

x=

D1 dfk + bgl + cjh − ( cfl + gjd + khb ) = D afk + bgi + cje − ( cfi + gja + keb )

n n

y=

D 2 ahk + dgi + cie − ( chi + gla + ked ) = D afk + bgi + cje − ( cfi + gja + keb )

z=

D3 afl + bhi + dje − ( dfi + hja + leb ) = D afk + bgi + cje − ( cfi + gja + keb )

(n a )n = a a =a

n a * n b = n ab n n

a na = b b

g) Quadratic Equation

d) Factoring ax + ay = a ( x + y )

ax 2 + bx + c = 0

a 2 − b 2 = (a + b )(a − b ) a 2 + 2ab + b 2 = (a + b )2 a 2 − 2ab + b2 = (a − b )2

(

a 3 + b3 = (a + b ) a 2 − ab + b2

x=

− b ± b 2 − 4 ac 2a

)

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CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-1 – MATHEMATICS

b) Right Triangle

If: 2

b − 4 ac > 0 , the roots are real and

-

c

unequal. 2

b − 4 ac = 0 , the roots are real and

b

equal. 2

b − 4 ac < 0 , the roots are imaginary.

h) Power of Ten ( p ) pico = 10 −12 (n)

nano = 10

−9

( μ ) micro = 10 ( m ) milli = 10 (c) (d )

a

A

−3

centi = 10 deci = 10

−6

−2

−1

deka = 101 hecto = 10 kilo = 10

2

3

mega = 10

(h) (k )

6

(M )

c a c sec A = b b cot A = a csc A =

c) Any Triangle

9

(G )

12

C

(T )

b

giga = 10 tera = 10

( da )

a sin A = c b cos A = c a tan A = b

a B

A c

2. Trigonometry

Law of sines

a) General Relationships

a b c = = sin A sin B sin C

sin 2 A + cos 2 A = 1 sec 2 A = 1 + tan 2 A

csc 2 A = 1 + cot 2 A 1 1 cos A = sin A = csc A sec A sin A cos A tan A = cot A = cos A sin A sin( A + B ) = sin A cos B + cos A sin B 2

sin A = 2 sin A cos A cos 2 A

= cos 2 A − sin 2 A

= 1 − 2 sin 2 A , = 2 cos 2 A − 1 A 1 − cos A sin = ± 2 2 A 1 − cos A tan = ± 2 1 + cos A A 1 + cos A cos = ± 2 2

Law of cosines 2 2 2

a = b + c − 2bc cos A

b 2 = a 2 + c 2 − 2ac cos B c 2 = a 2 + b 2 − 2ab cos C Law of tangents

A− B 2 = a −b A+ B a +b tan 2 B −C tan 2 = b−c B+C b+c tan 2 A−C tan 2 = a−c A+C a +c tan 2 tan

where b > c

where a > c

Newton's formula

c sin

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where a > b

C 2

=

a+b A− B cos 2

MATHEMATICS - Page 4/8 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-1 – MATHEMATICS

Tangents of half angles

b+c+d If p = 2 ( p − a )( p − b )( p − c ) 2 p tan = p−a

( p − a )( p − b )( p − c ) 2 p tan = p−b 2

tan =

= =

=

= = = =

a) Rectangle

2 , p( p − a )( p − b )( p − c ) a 2 sin B sin C 2 sin A 2 b sin A sin C 2 sin B c 2 sin A sin B 2 sin C bc sin A 2

ac sin B 2 ab sin C 2

Area: a * b

a b b) Parallelogram

a

( p − a )( p − b )( p − c ) p p−c

Area S

3. Plane Geometry

Area: a * b

b c) Triangle

a

c

d

Area: 0.5 * a * b

b b+c+d 2 Area: p * ( p − b ) * ( p − c ) * ( p − d ) If p =

d) Circle

Circumference: =

d) Hyperbolic x −x sinh x = e + e 2 x −x cosh x = e + e 2

Area: r c h s

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πD , = 2πr

2 2 = 0.25πD , = πr 0.25c 2 + h 2 =

2h

= 2*

h * ( D − h ) , = 2rsin

β 2

r − r 2 − 0.25c 2 ß πD , = 0.01745 rβ = 360 =

MATHEMATICS - Page 5/8 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-1 – MATHEMATICS

Where:

e) Circular Sector

n is the number of sides

s

n

= 0.5 rs, = 0.008727 r2ß ( β in °)

Area

nr 2 tan

1.7205 s2 2.5981 s2 3.6339 s2 4.8284 s2 6.1818 s2

5 6 7 8 9

ß

r

Area =

180° n

j) Trapezoid

f) Circular Segment

s

h r

ß

c c

b

Area Area

H

h

a

= 0.5 [b*(H+h) + ch + aH]

= 0.5 (rs - c*(r-h)) =

πr 2

ß c* ( r − h ) * 360 2

4. Solid Geometry

g) Circular Ring

d

a) Cube

Area

π 2 ( D − d2 ) 4

=

a c

D

b Volume: Surface area:

h) Ellipse

b) Cylinder

a Area

A

= abc = 2(ab+bc+ca)

=

π Aa 4

h D

i) Polygon s

Volume r

Area

= 0.5*n*s*r

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=

π 4

D 2h

Surface area: = πDh (without end surface) = πD (0.5D + h) (with end surface)

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CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-1 – MATHEMATICS

c) Pyramid g) Segment of a Sphere

s

h

h c

area of base h Volume = 3 perimeter of base s Lateral area = 2

r

Volume

=

Sphere surface

=

( c2 + 4h2 ) 4 π 2 (c + 8rh) = 4

d) Cone Volume =

h

π 3

Total surf

r 2h

Surface area =

r

π r (r 2 + h 2 )

⎛ c2 + 4h2 h ⎞ − ⎟ ⎜ 8h 3 ⎟⎠ ⎝

π h2 ⎜

π

h) Sector of a Sphere

h

c

Volume =

e) Frustum of a Cone

r

Total surface =

r

h

2 2 πr h 3

π

2

r ( 4h + c )

h

s

i) Torus

R Volume

=

π

d

(

)

∗ r 2 + rR + R 2 ∗ h

3 Surface area = πs ( R + r )

D

Volume (compl ring)

=

Surface (

=

f) Sphere

D

Volume =

π 6

"

)

π2 4

D d2

π2 Dd

D3

Surface area =

πD 2

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CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-1 – MATHEMATICS

My notes:

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CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-2 – STATISTICS

9-2 . Statistics

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CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-2 – STATISTICS

Table of Contents 1. Descriptive Statistics ........................................................................ 3 1.1 1.2 1.3 1.4

Definitions.......................................................................................................... 3 Basic.................................................................................................................. 3 Normal Probability Distribution.......................................................................... 3 Interval Estimation and Tables.......................................................................... 4

2. Statistical Estimation Tests .............................................................. 5 2.1 Generalities ....................................................................................................... 5 2.2 Test for the Equality of Two Variances ( σ 1 ,σ 2 ) of two Normal Population of Random Size, ( n1 , n 2 ) ............................................................... 6 2.3 Fisher Distribution Table ................................................................................... 7

3. Correlation Between Data – Regression.......................................... 8 3.1 Generalities ....................................................................................................... 8 3.2 Least Squared Lines ......................................................................................... 8

4. Temporal/Regionalized Series (Variables)....................................... 9 4.1 Stationnarity ...................................................................................................... 9 4.2 Variogram.......................................................................................................... 9 4.3 Raw Mix Control Tuning.................................................................................. 11

5. Sampling........................................................................................... 12 5.1 5.2 5.3 5.4 5.5 5.6 5.7

Golden Rules................................................................................................... 12 Fundamental Error (FE) .................................................................................. 12 Minimum Representative Weight (MRW)........................................................ 13 Estimation of the Maximum Particle Size........................................................ 14 Minimum Number of Observations ................................................................. 14 Mechanical Sampling ...................................................................................... 15 Manual Sampling on Conveyor Belt................................................................ 15

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CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-2 – STATISTICS

1.

Descriptive Statistics

1.1 Definitions •

Statistics is the science of drawing conclusions about a population based on an analysis of sample data from that population.

•

Population: values that can be taken by a variable.

•

Sample: drawing of n values of the variable taken from the population.

•

Random Variable = X = ( xi ) .

•

Probability Distribution = P ( xi ) . It describes the random variable probability of occurrence and is described by its parameters. (Example: Normal distribution is described by μ and σ , see below).

•

Statistic = Any function of the sample data.

•

Estimator = An estimator of a parameter is a statistic, which corresponds to the parameter. For instance :

ƒ The sample mean ( x ) is the estimator of the actual population mean μ ƒ The sample variance ( S 2 ) is the estimator of the actual population variance σ 2 •

Interval Estimation: An interval estimation of a parameter is the interval between 2 statistics that includes the true value of the parameter with a given probability (1- α ).

1.2 Basic

∑ (xi − x ) 2 n

n

∑ xi

•

Arithmetical Mean = x =

•

2 Variance = S X

-

i =1

Standard Deviation = S X =

n

i =1

n −1

2 2 2 2 2 2 SX +Y = S X + S Y and S aX = a ⋅ S X a : Coefficient, X = ( xi ) , Y = ( yi ) : two series of independent values.

∑ (xi − x ) * ( yi − y ) n

•

Covariance = Average of the products of paired deviations: COV ( X ,Y ) = i =1

n

1.3 Normal Probability Distribution •

The most often used probability distribution is the Normal probability distribution: 2 1 ⎛ x − x ⎞⎟ ( − ⎜⎜ ) dZ 1 2 ⎝ σ ⎟⎠ = e

dx

σ 2π

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CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-2 – STATISTICS

Central Limit Theorem

•

For a group of n independent sampling units drawn from a population of mean the sampling distribution of x =

⎛ σ2 Said: x → Ζ ⎜ μ , ⎜ n ⎝

1 n

n

∑

i =1

μ

and variance σ 2 ,

x i is approximately Normal with mean μ and variance

σ2 n

.

⎞ ⎟. ⎟ ⎠

1.4 Interval Estimation and Tables a) •

If the Variance σ 2 is Known The confidence interval, with a probability of (1- α ), in which for any samples of the population with a given unknown mean ( μ ) and known variance ( σ 2 ), the average x of the sample should range is given by:

x−Ζα 2

σ n

≤ μ ≤ x+Ζα 2

σ n

b) Normal Gaussian Distribution Table

α

α

Zα

0.25 0.159 0.10 0.05 0.025

0.6745 1 1.28 1.64 1.96

0.0232 0.01 0.005 0.00135 0.001

Zα 2 2.32 2.57 3 3.09

Example: Estimation of the true LHV mean ( μ ) of liquid waste fuel An n-size sample (n=100) of different waste fuel shipments gave a mean x = 5.5 MCal/kg. Standard deviation σ of the waste fuel shipment population (considered infinite) is supposed to be 1Mcal/kg. Then, according to the Central Limit Theorem, x follows a Normal distribution probability with σ2 a variance of = 1 / 100 = 0.01 .

n

Thus, we are sure at 1 − α = 90% (then

α

= 0.05 ) that the mean ( μ ) is between 2 x ± 1.64 × 0.01 = [5.5 − 0.164 ,5.5 + 0.164 ] = [5.336 ,5.664 ] .

Remark:

If the population from which the sample is taken, is not infinite (let’s say population size=800), then we have to use a corrective factor of

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1− n

N

= 1 − 100

800

= 0.935 .

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CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-2 – STATISTICS

c) •

If the Variance σ 2 is Unknown and Sample Size n<30, It has to be approximated by the variance S 2 of the sample. The Normal distribution is replaced by a t distribution (Student distribution). The estimated interval, with a confidence of (1- α ) and n-1 degree of freedom, is given by:

x − tα 2

S S ≤ μ ≤ x + tα , n −1 n , n −1 n 2

Example With the data as above assuming S=1Mcal/kg, then with the same confidence (90%) and say 20

(21

samples)

degrees

of

freedom,

[5.5 − 0.172,5.5 + 0.172] = [5.328 ,5.672] .

(μ )

is

between:

x ± 1.72 × 0.01 =

d) Student Fisher Distribution Table

υ 1 2 3 4 5 10 15 20 40 120

2.

t 0.005 ,υ

t0.01,υ

t 0.025 ,υ

t 0.05 ,υ

t 0.10 ,υ

t 0.25 ,υ

t 0.45 ,υ

63.66 9.92 5.84 4.6 4.03 3.17 2.95 2.84 2.70 2.62

31.82 6.96 4.54 3.75 3.36 2.76 2.60 2.53 2.42 2.36

12.71 4.3 3.18 2.78 2.57 2.23 2.13 2.09 2.02 1.98

6.31 2.92 2.35 2.13 2.02 1.81 1.75 1.72 1.68 1.66

3.08 1.89 1.64 1.53 1.48 1.37 1.34 1.32 1.30 1.29

1 0.817 0.765 0.741 0.727 0.700 0.691 0.687 0.681 0.677

0.158 0.142 0.137 0.134 0.132 0.129 0.128 0.127 0.126 0.126

Statistical Estimation Tests

2.1 Generalities •

A statistical hypothesis is a statement about the values of the parameters of a probability distribution.

•

Null hypothesis (H o ) : A = B , Alternative hypothesis (H 1 ) : A ≠ B .

•

To test a hypothesis, we take a random sample from the population under study, compute an appropriate test statistic and then either reject or fail to reject ( H o ) with a α risk of rejecting H o although H o is true.

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CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-2 – STATISTICS

2.2

Test for the Equality of Two Variances ( σ 1 ,σ 2 ) of two Normal Population of Random Size, ( n1 , n 2 )

(Excel Function FTEST) Test Description • H o : σ 12 = σ 22 , H 1 : σ 12 ≠ σ 22

•

S2 We compute the statistic Fo = 1 , where F = Fisher Distribution S 22

•

We reject H o if Fo > Fα or if Fo < F ⎛ α ⎞ , n1 −1, n2 −1 1−⎜ ⎟ ,n1 −1, n2 −1, 2 ⎝2⎠

•

Where Fα

and F ⎛ α ⎞ denote the upper and lower percentage points of 2 ,n1 −1,n2 −1 1−⎜ ⎟ , n1 −1, n2 −1 2 ⎝2⎠ the F distribution with n1 − 1 and n 2 − 1 degrees of freedom, respectively.

•

As the table for the F table gives only the upper tail points of the F, so to find F ⎛ α ⎞ we 1−⎜ ⎟ ,n1 −1,n2 −1 ⎝2⎠

α

1

must use: F ⎛ α ⎞ = (be careful about n1 and n 2 , which are inverted). 1−⎜ ⎟ , n1 −1, n2 −1 Fα , n2 −1, n1 −1 ⎝2⎠ 2 Example 1: Cement sampling: We want to determine the best way of sampling cement. We can compare the variances of two sets of samples collected at the mill discharge by two different ways. The H o hypothesis would be that there is no difference between both ways of sampling (true variances equal). If the result says that according to the samples, there is a difference, then the best sampling method could be the one with the lowest variance (one-sided alternative hypothesis). SSB measured: #1 way: (4350, 4365, 4850, 4750, 4580, 4600, 4450, 4740), #2 way: (4500, 4520, 4800, 4420, 4360, 4250, 4400, 4380)

•

H o : σ 12 = σ 22 , H 1 :σ 12 ≠ σ 22 (two-sided alternative hypothesis) 8

∑ (xi − 4586 ) 2

After computing: x1 = 4586 , x 2 = 4454

•

Fo =

S12 =

i =1

8 −1

= 34796 , S 2 2 = 26598

34796 = 1.308 < F0.05 = 4.99 26598 ,8 −1,8 −1

2 − and F.975 ,7 ,7 = ( F0.025 ,7 ,7 ) 1 = ( 4.99 ) −1 = 0.20 <1.308

The test yields not to reject H o : the measurements don’t allow us to conclude that #1 way of sampling is significantly, with 5% confidence, different than #2 (even if S 1 > S 2 ). The excel function is FINV(0.025,7,7).

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CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-2 – STATISTICS

2.3 Fisher Distribution Table (Calculated for the upper 2.5% of the F distribution (in our case, when α = 5% )). F(0.025, n1,n2)

1 2 3 4 5 6 7 8 9 10 15 20 25 30 40 50 60 70 80 90 100 200

1 647.79 799.48 864.15 899.60 921.83 937.11 948.20 956.64 963.28 968.63 984.87 993.08 998.09 1001.40 1005.60 1008.10 1009.79 1011.01 1011.91 1012.61 1013.16 1015.72

2 38.51 39.00 39.17 39.25 39.30 39.33 39.36 39.37 39.39 39.40 39.43 39.45 39.46 39.46 39.47 39.48 39.48 39.48 39.49 39.49 39.49 39.49

3 17.44 16.04 15.44 15.10 14.88 14.73 14.62 14.54 14.47 14.42 14.25 14.17 14.12 14.08 14.04 14.01 13.99 13.98 13.97 13.96 13.96 13.93

Ex: F(0.025,5,10)=4.24 4 5 6 7 12.22 10.01 8.81 8.07 10.65 8.43 7.26 6.54 9.98 7.76 6.60 5.89 9.60 7.39 6.23 5.52 9.36 7.15 5.99 5.29 9.20 6.98 5.82 5.12 9.07 6.85 5.70 4.99 8.98 6.76 5.60 4.90 8.90 6.68 5.52 4.82 8.84 6.62 5.46 4.76 8.66 6.43 5.27 4.57 8.56 6.33 5.17 4.47 8.50 6.27 5.11 4.40 8.46 6.23 5.07 4.36 8.41 6.18 5.01 4.31 8.38 6.14 4.98 4.28 8.36 6.12 4.96 4.25 8.35 6.11 4.94 4.24 8.33 6.10 4.93 4.23 8.33 6.09 4.92 4.22 8.32 6.08 4.92 4.21 8.29 6.05 4.88 4.18

8 7.57 6.06 5.42 5.05 4.82 4.65 4.53 4.43 4.36 4.30 4.10 4.00 3.94 3.89 3.84 3.81 3.78 3.77 3.76 3.75 3.74 3.70

9 7.21 5.71 5.08 4.72 4.48 4.32 4.20 4.10 4.03 3.96 3.77 3.67 3.60 3.56 3.51 3.47 3.45 3.43 3.42 3.41 3.40 3.37

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10 6.94 5.46 4.83 4.47 4.24 4.07 3.95 3.85 3.78 3.72 3.52 3.42 3.35 3.31 3.26 3.22 3.20 3.18 3.17 3.16 3.15 3.12

15 6.20 4.77 4.15 3.80 3.58 3.41 3.29 3.20 3.12 3.06 2.86 2.76 2.69 2.64 2.59 2.55 2.52 2.51 2.49 2.48 2.47 2.44

20 5.87 4.46 3.86 3.51 3.29 3.13 3.01 2.91 2.84 2.77 2.57 2.46 2.40 2.35 2.29 2.25 2.22 2.20 2.19 2.18 2.17 2.13

25 5.69 4.29 3.69 3.35 3.13 2.97 2.85 2.75 2.68 2.61 2.41 2.30 2.23 2.18 2.12 2.08 2.05 2.03 2.02 2.01 2.00 1.95

30 5.57 4.18 3.59 3.25 3.03 2.87 2.75 2.65 2.57 2.51 2.31 2.20 2.12 2.07 2.01 1.97 1.94 1.92 1.90 1.89 1.88 1.84

40 5.42 4.05 3.46 3.13 2.90 2.74 2.62 2.53 2.45 2.39 2.18 2.07 1.99 1.94 1.88 1.83 1.80 1.78 1.76 1.75 1.74 1.69

50 5.34 3.97 3.39 3.05 2.83 2.67 2.55 2.46 2.38 2.32 2.11 1.99 1.92 1.87 1.80 1.75 1.72 1.70 1.68 1.67 1.66 1.60

60 5.29 3.93 3.34 3.01 2.79 2.63 2.51 2.41 2.33 2.27 2.06 1.94 1.87 1.82 1.74 1.70 1.67 1.64 1.63 1.61 1.60 1.54

70 5.25 3.89 3.31 2.97 2.75 2.59 2.47 2.38 2.30 2.24 2.03 1.91 1.83 1.78 1.71 1.66 1.63 1.60 1.59 1.57 1.56 1.50

80 5.22 3.86 3.28 2.95 2.73 2.57 2.45 2.35 2.28 2.21 2.00 1.88 1.81 1.75 1.68 1.63 1.60 1.57 1.55 1.54 1.53 1.47

90 5.20 3.84 3.26 2.93 2.71 2.55 2.43 2.34 2.26 2.19 1.98 1.86 1.79 1.73 1.66 1.61 1.58 1.55 1.53 1.52 1.50 1.44

100 5.18 3.83 3.25 2.92 2.70 2.54 2.42 2.32 2.24 2.18 1.97 1.85 1.77 1.71 1.64 1.59 1.56 1.53 1.51 1.50 1.48 1.42

STATISTICS - Page 7/16 Version September 2010

200 5.10 3.76 3.18 2.85 2.63 2.47 2.35 2.26 2.18 2.11 1.90 1.78 1.70 1.64 1.56 1.51 1.47 1.45 1.42 1.41 1.39 1.32

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-2 – STATISTICS

3.

Correlation Between Data – Regression

3.1 Generalities •

Goal: express a dependant variable ( Y : ( y i )i =1ton ) as a function of one or a series of p independent variables X j : ( X j = ( x j ,i ) j =1top ,i =1ton ) ).

•

Y E = b0 + b1 ⋅ X 1 + .. + b p ⋅ X p ƒ Y E = estimated dependant variable, X j = independent variables. ƒ We have n observation for each variable.

3.2 Least Squared Lines •

The method minimizes the deviation E ( Ei ) between the points and the line. - SST = total sum of square of the variable of interest = y n x B1=y/x yi − y 2 Y i =1

∑(

)

E=Y-YEst

Y

-

B0

∑ (E i − E ) 2 n

YEst

SSE = sum of square of errors =

i =1 SSR = sum of square explained by the regression line: SST = X SSR+SSE We want to optimize SSR/SSE. Thus we test the hypothesis that the slope B1 equals 0: H o : B1 = 0 , H 1 : B1 ≠ 0 .

-

• •

Under H o , the ratio (SSR/p)/(SSE/(n-p-1)) follows a Fisher distribution with p and n-p-1 degrees of freedom (excel function FINV (α, p, n-p-1)).

•

If Fα is high, then H o is rejected and with a certain significance α , we assume the regression is significant.

Coefficient of Determination R2 • The coefficient of determination R2=SSR/SST gives the proportion of variation in the dependent variable ( Y : ( y i )i =1 ton ) explained by the regression line. The coefficient of correlation is defined by: r =sqrt (R2) H0: there is no correlation n=5, p=1, SST=0.051+0.019, MSR=0.051/1=0.051, MSE=0.019/3=0.0063, F=0.051/0063=8.05, R2 = 0.051 / (0.051 + 0.019) = 0.73, r = 0.85 Critical F value (α = 0.025), F1,3,0.025 = 17.44 > 8.05 The ratio belongs to the F distribution We cannot reject H0, the regression is not significant.

.75 .7 .65 .6

SO3

•

.55 .5 .45 .4

Y = 2.077 - .032 * X; R^2 = .727

.35 42

43

44

45

46

47

48

49

50

51

52

CaO

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CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-2 – STATISTICS

4.

Temporal/Regionalized Series (Variables)

4.1 Stationarity •

The series X (t ) is stationary if its average X (t ) and its variance S 2 (t ) are constant (over time or over the region of study) and if the covariance COV ( X (t ), X (t' )) does not depend on t and t' only on the difference (distance) t' −t = Δt (= h ) .

but

4.2 Variogram a) •

Variogram Construction A variogram is a plot of the average difference of a selected variable (C3S for example) between pairs of units selected as a function of time, where the pairs are chosen in whole-number multiples (e.g. every minute, 2 minutes, 1 meter, 2 meters, …). 2 with : ⎞ N ⎛⎜ x j − x j +h ⎟ - j : numbering of the sample’s value ⎟ j =1 ⎜ ⎝ ⎠ - N: number of pairs of sample with a specific time or γ X (h ) = spatial distance (=h) between values of a pair. 2 ⋅( N − 1)

∑

Example: The C3S values of kiln feed samples are: Sample# 1 2 3 4 Time 1:00 2:00 3:00 4:00 C3S (%) 54.2 57.8 59.8 61.2

5 5:00 60.0

6 6:00 56.0

Then we can calculate the one-hour pair difference: Pair# 1 2 3 4 5 6 Diff in pair 3.6 2 1.4 -1.2 -4 -4 Square diff 12.96 4 1.96 1.44 16 16

7 7:00 52.0

7 0 0

8 0.4 0.16

8 8:00 52.0

9 9:00 52.4

9 4.6 21.16

10 10:00 57.0

Sum 73.7

Two rules for variogram construction • Collect enough units (N) to get a statistical population (at least 30 samples for a short term experiment and 60 samples for a long term); the short term intends to define very precisely the random heterogeneity term (nugget effect, refer below).

•

The number N should reach half the total amount of samples collected (N>n/2).

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CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-2 – STATISTICS

b) Variogram Interpretation X

Interpretation of the limit of variogram (h) when h increases • Whatever the variable is, beyond a certain value of h, the variable ceases to be correlated with itself. It is because the phenomenon taking place has no longer any memory of a past long gone (see case 2 and case 3 where the variable level off at a sill generally equal to the variance of the variable).

•

This is true for all raw mix analyses, which are limited in terms of the values they can take.

•

However, over a short period of time (a few hours), the signal may well drift. (See graph below). In such a case, the variogram will tend to increase instead of stabilizing itself around σ x2 .

The "Nugget Effect" • Many variables, especially those obtained from data measured with a dispersive method (analytical, sampling errors, etc.), present a slight or marked degree of strictly random variations from one value to the next.

•

•

As a rule, a variable presenting a "smooth" graph (# 3) when plotted presents a low to non-existent "nugget effect". (i.e. due to variability at a scale smaller than the sampling distance). A "noise" (# 1) presents all its variance as a "nugget effect" ( σ x2 being called the "nugget effect variance").

t

Signal is drifting

γ X(h)

h

X γ x (h)

2 2 σ x = σ xn

#1 Nugget effect t

h γ x (h)

X

2

σx

#2 Nugget effect

2 σxn

t

h γ x (h)

X

2 σx

#3 No nugget effect h

t

Limitations in h value • If N values of X are available, shifts of more than N/2 should not be considered.

Regionalization and prediction • A very frequent pattern of variogram is shown as below:

γ X (h )

• •

The value of the signal at time t + ho is in fact dependent of all values taken by X between t and t + ho.

•

x x ,x x If all values b i +1 i + h+1 are known, then i + h can be predicted much better than by saying that it is σ2 randomly distributed with a variance x .

•

In fact, the variance of the prediction, at its best, will be

2 σx

2 σ xn

h

2 The span of values of ho for which γx (h) is below σ x is called the "area of regionalization" or the range.

Area of ho regionalization

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γX

2 close to 2 which is much smaller than σ x .

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CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-2 – STATISTICS

Pseudo-periodicity • The periodic variations can be self-sustained (control cycle, oscillator, etc.) or induced by a periodic phenomenon (buckets of elevator are unevenly distributed, correction interval of raw meal).

•

•

Even if the periodicity is blurred on the graph of the signal by random noises or variations of the period, the variogram will tend to underline.

X

γ x (h) 2 2 σx h

t

Pseudo Periodic signal

1 Pseudo-Period

The variogram will hit a maximum, above the total variance σ x2 , for a shift h of exactly 1 period. Maximum and minimum will repeat themselves and fade away as h increases. The fading will be quick if the pseudo period varies much but slow if the signal is truly periodic.

γ x (h)

X

h

t

Periodic signal

4.3 Raw Mix Control Tuning “Correctogram” is a simple statistics tool which can be used to determine whether over-control or undercontrol is occuring in a control loop. For spot checking, a plot of the correctogram can be used. Plot the cartesian coordinates (x, y) where: x = values of control parameter – set point, at time t y = values of control parameter – set point, at time t – Δt Δt is the sampling interval. Example: Time 2:00 4:00 6:00 8:00 10:00 12:00 14:00 16:00 18:00 20:00 22:00

C3S 64.1 58.5 58.9 61.7 56.7 59.2 54.5 60.8 55.1 58.3 59

SP 60 60 60 60 58 58 58 58 58 58 58

C3S – SP 4.1 -1.5 -1.1 1.7 -1.3 1.2 -3.5 2.8 -2.9 0.3 1.0

(x , y) –– (4.1,-1.5) (-1.5,-1.1) (-1.1,1.7) (1.7,-1.3) (-1.3,1.2) (1.2,-3.5) (-3.5,2.8) (2.8,-2.9) (-2.9,0.3) (0.3,1.0)

4 3 2 1 0 -5

-4

-3

-2

-1

0

1

2

3

4

5

-1 -2 -3 -4 -5

SLOPE INTERPRETATION & CORRECTIVE ACTION =0 1 > slope > 0 =1 >1

Perfectly tuned control. All off-target values for the control parameter are due to random variations (materials, feeder accuracy, etc.) Undercontrolling. Multiply gain by (1 + slope). No control taking place. Divergent control: gain value has wrong sign.

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STATISTICS - Page 11/16 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-2 – STATISTICS

0 > slope > -1 Overcontrolling. Divide gain by (1 – slope). = -1 Overcontrolling is inducing a cycle with frequency = 2 x sampling interval. Divide gain by 2. < -1 Divergent cycling due to severe overcontrolling. Divide gain by (1 – slope). The method is applicable to control response analysis in general. It can be incorporated as an internal tuning device in a control algorithm. Analyses of non linear control response can be performed by using polynomial fit rather than linear regression.

5.

Sampling

5.1 Golden Rules •

The MRW.

•

The sampling method must allow every particle the same chance of being collected.

5.2 Fundamental Error (FE) Calculation • This error can never be cancelled because it is intrinsic to the material. However, we want to collect the right size (MRW) of the sample based on this Fundamental Error (P. Gy’s theory).

•

σ 2 (FE ) = C x d M 3 x

(1 − τ ) m

With:

ƒ d M : Top particle size (95% passing) in cm. ƒ τ : sampling proportion (usually quite small, then 1- τ = 1) ƒ m : sample weight in g. ƒ C : Constant characterizing the material sampled, in g / cm 3 •

C = fcl g with ƒ f = Particle shape factor. (= 0.5 usually, ranges between 0 and 1) ƒ l ƒ g

•

= 1 when cubic, = 0.2 when flat, = 0.5 when spheroidal = liberation factor [0 to 1] = 0 if homogeneous, = 1 if particles completely distinct, = .001 for homogeneous raw mix, = .2 medium, = .3-8 heterogeneous = factor describing the particle size distribution

If we call “size range” the ratio d M / d m of the upper size limit d M : (about 5% oversize) to the lower size limit d m : (about 5% undersize):

ƒ Large size range ( d M / d m > 4): g = 0.25, medium size range (4 to 2): g = 0.50, small size range (< 2): g = 0.75, uniform size ( d M / d m = 1): g = 1.00 •

(

c = Mineralogical composition factor g / cm 3 c=

(

⎛ 1 − ai ⎞ c ⎟ . ρ i ai + (1 − ai ) ρ i ai ⎠

∑ pi ⎜⎝ i

)

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)

STATISTICS - Page 12/16 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-2 – STATISTICS

With:

ƒ pi = proportion of material I in the mix (%) ƒ a i = concentration of the “critical” within the material I (%) in mass ( g of CaO / g of solid )

(

ƒ pi = volumetric weight of the material i g / cm 3

)

ƒ ρ ic = volumetric weight of the “initial” in the material Usually we take ρ i = ρ ic Example: Mix is crushed at 12.5 mm of 75% lime and 25% clay, CaO is the critical Sample weight = 50 kg. l = 0.3 f = 0.5 CaO lime content = 52%, CaO clay content = 24% ρCaO = 2.7 g / cm 3 , ρ lime = 2.7 , ρ clay = 2.7, g = 0.25

⎛ 1 − 0.52 ⎞ ⎛ 1 − 0.24 ⎞ 3 c = 0.75 x ⎜ ⎟ x 2.7 + 0.25 x ⎜ ⎟ x 2.7 = 1.869 + 2.137 = 4.00 g / cm ⎝ 0.52 ⎠ ⎝ 0.24 ⎠ Then:

C = f l c g = 0.5 x 0.3 x 4.0 x 0.25 = 0.15 g / cm 3

And:

σ (FE ) =

(1.25 )3 x 0.15 50 ,000

= 2.4 .10 −3 is the fundamental error standard deviation.

Then the 95% probability confidence interval ± 2 σ ( FE ) is 0.0048 and then CaO content confidence interval is: 052.( 1 ± 2σ ( FE )) = 0.52 ± 0.048% CaO . (Considering that 1−τ ≈ 1)

5.3 Minimum Representative Weight (MRW) a)

Lafarge Corp Simplified Formula

d3

•

MRW = 18. f .ρ .

•

In case of material encountered in cement plant, we usually have σ ( FE ) 2 <0.06.

σ ( FE ) 2

.

Example 1 estimation of the MRW For quarry crushed stone with: f = 0.5 , ρ = 2.6 g / cm 3 , d = 1.75cm , σ ( FE ) 2 = 0.01

MRW = 18 × 0.5 × 2.6 × 1.75 3 / 0.01 = 12.54 kg

b) Estimation of the MRW (P. Gy’s formula) •

(

What is the MRW considering the previous lot C = 0.15 g / cm

3

)?

Passing 95% = d M = 4.0 cm with σ ( FE ) = 0.04 (be careful, it is a relative standard deviation), then, MRW =

3 C .d M

σ ( FE ) 2

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=

0.15 x 4 3

(0.04 )2

= 6 kg

STATISTICS - Page 13/16 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-2 – STATISTICS

5.4 Estimation of the Maximum Particle Size •

Assuming we want to sample a maximum of 5 kg sample with a tolerate standard deviation of

σ = 0.04

Then:

a)

3 dM

=

Mσ 2 C

5000 x 0.04 2 = 3.8 cm 0.15

d M =3

Rule of Thumb: Maximum Particle Size (mm) Min sample Coal (ISO1988), kg Min Sample Aggregate, ASTM D75, kg

10

20

30

40

50

60

75

90

0.6 10

0.8 25

60

80

3 100

120

150

175

ASTM for the aggregate industry is very safe.

5.5 Minimum Number of Observations •

Once the right size (MRW) of the sample is calculated, we want to determine how many samples (n) have to be collected to have the acceptable knowledge (precision P) of the parameter ( X ) we are interested in, with an afforded risk α .

•

The larger the sample size, the closer we can expect the sample mean X to be to the population

• •

mean X . Refer to the ‘Central Limit Theorem’ above. The reliability of X as an estimate of X is measured by the standard error of the mean which is simply the standard deviation of the sample mean. σ 2X Rule of thumb: n = σ2 X where:

ƒ σ 2X is the variance of the material stream and, σ 2 is the variance of the mean (the variability X desired in the result). Remark: Each sample must have the MRW in order to have a right observation of the parameter that we want to have estimated. Example: The small-scale random heterogeneity of the raw mix, expressed in C3S variance, at mill outpout is 10, thus σ 2 X =10. We would like to decrease this random heterogeneity to 2, thus σ 2 =2, X Then to achieve this goal we have to sample 10/2=5 increments. Normally they have to be collected closely to one another (e.g. 30 second interval).

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STATISTICS - Page 14/16 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-2 – STATISTICS

5.6 Mechanical Sampling (Sampling ratio 1/1000 to 1/10)

a)

Cutter Width and Velocity – Rules of Extraction Correctness

(for flow < 500 m 3 / h ). ƒ d M = Maximum particle diameter ƒ W = Actual Cutter opening ƒ W0 = Minimum theoretical cutter width

b) First rule of Extraction Correctness ƒ For d M > 3 mm : W ≥ Wo = 3 d M ƒ For d M ≤ 3mm : W ≥ Wo = 10 mm c)

Second Rule of Extraction Correctness

•

Irrespective of d M , if the actual cutter width is W = n Wo (with n ≥ 1 ) then the cutter velocity V should not exceed Von = (1 + n ) ⋅ 0.3 m / s

•

Economical Optimum is : W = W0 and V = 0.6 m / s

d) Interval of Time between Increment •

No more than 5 minutes, usually every 30 seconds.

•

Make sure the number of increments making up the sample is in excess of 6 (a best is 30, ASTM 2234 (coal) recommends 15 increments for cleaned and 35 for uncleaned coal).

5.7 Manual Sampling on Conveyor Belt a)

When the Belt is Stopped

•

Sample enough material with regard to MRW.

•

Sample over all the width of the belt making sure to collect everything and perpendicular to the belt.

•

The length of sampling over the belt should be greater than the width of the belt.

•

Make-up the sample with several increments (more than 6 at least) to get the MRW.

b) When the Belt Keeps Running •

Basic rule: extract a full cross-cut section of the flow stream, in several increment if necessary.

•

The manual sampling device width must be at least 2.5 times the bulk material top size.

•

Interval of time between increment. ƒ no more than 5 minutes, usually every 30 seconds. ƒ number of increments in excess of 6.

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CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-2 – STATISTICS

My notes:

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CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-3 – THERMODYNAMIC AND CHEMICAL DATA

9-3. Thermodynamic and Chemical Data

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THERMODYNAMICS AND CHEMISTRY DATA – Page 1/14 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-3 – THERMODYNAMICS AND CHEMISTRY DATA

Table of Contents 1. Thermodynamic Properties .............................................................. 3 1.1 Heat Capacity and Enthalpy ................................................................................ 3 1.2 Estimation of Cp and Cpm ................................................................................... 4 1.3 Table 1: Heat of Reaction at 25°C ....................................................................... 5 1.4 Table 2: Heat of evaporation of water ................................................................. 5

2. Data ..................................................................................................... 6 2.1 2.2 2.3 2.4 2.5

Table 3: Some Properties of the Elements.......................................................... 6 Table 4: Properties of Typical Components ........................................................ 8 Table 5: Oxides and Other Definitions................................................................. 9 Table 6: Correlation constants for calculation of Cp in kcal/kg.°K..................... 10 Table 7: Cp mean – reference 0ºC .................................................................... 12

3. Psychrometric Chart........................................................................ 13

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THERMODYNAMICS AND CHEMISTRY DATA – Page 2/14 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-3 – THERMODYNAMICS AND CHEMISTRY DATA

1. 1.1

Thermodynamic Properties Heat Capacity and Enthalpy

Heat capacity • It is function of the system conditions:

⎛ ∂H ⎞ ⎟ ⎝ ∂T ⎠ p

At constant pressure: C p = ⎜

⎛ ∂U ⎞ Cv = ⎜ ⎟ ⎝ ∂T ⎠ v

At constant volume:

Enthalpy

Cp

Cp =

∂H ∂T dH dT T

Temperature

Enthalpy • No absolute value, only changes in enthalpy can be calculated. Integrating over the temperature change: T2

ΔH = H ( T2 ) − H ( T1 ) = ∫ C p (T) dT T1

Enthalpy ∆H

T2

ΔH = ∫ Cp(T ) dT Cp

T1

∆H T1 Temperature

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T2

THERMODYNAMICS AND CHEMISTRY DATA – Page 3/14 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-3 – THERMODYNAMICS AND CHEMISTRY DATA

Mean heat capacity Cpm • It is the enthalpy change divided by the temperature difference: T2

∫ Cp (T) dT

Cp m =

H 2 − H 1 T1 = T2 − T1 T2 − T1

Cpmean

Cp

Cpm =

ΔH T2 − T1

Cpm ∆H T1 Temperature

•

1.2

T2

In the more familiar form used in heat and mass balances: Q = mCp m ΔT

Estimation of Cp and Cpm

• Cp for different gases and materials at a given temperature can be estimated with the following correlation:

Cp (T ) = a + b.T + c.T 2 + d .T −2 The constants a, b, c and d are given at the Table 6, at the end of the chapter. • Cpm can be obtained from the integration of the Cp(T) correlation • As previously given, the average or Cp mean between T and a reference T0:

T 3 − T03 ⎛1 1 ⎞ T 2 − T02 + c× − d × ⎜⎜ − ⎟⎟ a × (T − T0 ) + b × 2 3 ⎝ T T0 ⎠ Cp m (T ) = T − T0 • The Lafarge thermodynamic.xla add-in calculates Cpm(T) in kcal/kg.°C using the above equation with a reference temperature T0 = 0°C (273.15°K) • Note:

1.0

Btu cal kcal = 1.0 = 1.0 lb.° F g.(°C ⋅ or ⋅ ° K ) kg.(°C ⋅ or ⋅ ° K )

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THERMODYNAMICS AND CHEMISTRY DATA – Page 4/14 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-3 – THERMODYNAMICS AND CHEMISTRY DATA

1.3

Table 1: Heat of Reaction at 25°C C C CO S SO2 S H2 H2 CaO

1.4

+ + + + + + + + +

½ O2 O2 ½ O2 O2 ½ O2 1½ O2 ½ O2 ½ O2 CO2

→ → → → → → → → →

CO CO2 CO2 SO2 SO3 SO3 H2Ogas H2Oliquid CaCO3

+ + + + + + + + +

26.416 kcal/gmole C 94.051 kcal/gmole C 67.636 kcal/gmole CO 70.960 kcal/gmole S 23.490 kcal/gmole SO2 94.450 kcal/gmole S 57.798 kcal/gmole H2 (LHV) 68.317 kcal/gmole H2 (HHV) 42.499 kcal/gmole CaO

Table 2: Heat of evaporation of water Temperature (°C) 0 10 15 20 25 30 40 50 60 70 80 100

Heat of evaporation (kcal/kg) 597.5 591.8 589.0 586.2 583.4 580.6 574.9 569.1 563.3 557.5 551.5 539.1

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THERMODYNAMICS AND CHEMISTRY DATA – Page 5/14 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-3 – THERMODYNAMICS AND CHEMISTRY DATA

2.

Data

2.1

Table 3: Some Properties of the Elements ELEMENT

SYMBOL

ATOMIC #

ATOMIC WEIGHT (g)

Actinium

Ac

89

(227)

10.0

1600

3200

Aluminum Americium Antimony Argon Arsenic Astatine Barium

Al Am Sb Ar As At Ba

13 95 51 18 33 85 56

26.9815 (243) 121.75 39.948 74.9225 (210) 137.34

2.694 11.7 6.7 17832e-3 5.73

660.46 1200 630.75 -189.2 815 (36 at)

2467 2607 1750 -185.7 613(sub)

3.59

725

1640

Berkelium Beryllium Bismuth Boron Bromine Cadmium

Bk Be Bl B Br Cd

97 4 83 5 35 48

(247) 9.0122 208.98 10.811 79.909 112.4

1.84 9.80 2.45 (Br2)3.119e-3 8.64

1278+5 271.3 2300 (Br2)-7.2 320.9

2970 1560 2550 (sub) 58.78 765

Calcium Californium Carbon Cerium Cesium Chlorine Chromium

Ca Cf C Ce Cs Cl Cr

20 98 6 58 55 17 24

40.08 (251) 12.01115 140.12 132.905 35.453 51.996

1.55

839+2

1484

(grap) 2.25 6.78 1.87 3.214 e-3 7.507

3652-3697 798 28.4 -100.98 1857+20

4827 3257 678.4 -34.6 2672

Cobalt Copper Curium Dysprosium Einsteinium Erbium

Co Cu Cm Dy Es Er

27 29 96 66 99 68

58.9332 63.54 (248) 162.5 (254) 167.26

8.7 8.94

1495 1083.4

2870 2567

8.56

1409

2335

Europium Fermium Fluorine Francium Gadolinium Gallium Germanium

Eu Fm F Fr Gd Ga Ge

63 100 9 87 64 31 32

151.96 (253) 18.9984 (223) 157.25 69.72 72.59

5.24

820

1700

(F2)1.696e-3

-219.62

-188.14

7.95 5.9 5.46

1313 29.78 937.4

3233 2403 2830

Gold Hafnium Helium Holmium Hydrogen Indium

Au Hf He Ho H In

79 72 2 67 1 49

196.967 178.49 4.0026 164.93 1.00797 114.82

19.3 13.08 1.785 e-4

1064.43 2227 -272.2 (26atm)

2807 4602 -268.93

(H2) 8.99 e-5 7.28

-259.14 156.61

252.87 2080

Iodine Iridium

I Ir

53 77

126.9044 192.2

(I2)4.94 22.64

113.5 2410

184.35 4130

Iron

Fe

26

55.847

7.9

1535

2750

Krypton

Kr

36

83.8

3.708 e-3

-156.6

-152.31

Lanthanum

La

57

138.91

6.16

920

3430

Lead

Pb

82

207.19

11.343

327.5

1740

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

VOLUMIC 3 MASS (g/cm )

FUSION TEMP.(C°)

EVAP. TEMP. (°C)

THERMODYNAMICS AND CHEMISTRY DATA – Page 6/14 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-3 – THERMODYNAMICS AND CHEMISTRY DATA

ELEMENT

Lithium

SYMBOL

Li

ATOMIC #

ATOMIC WEIGHT

3

6.939

(g)

VOLUMIC 3 MASS (g/cm )

FUSION TEMP.(C°)

EVAP. TEMP. (°C)

.53

180.5

1347

Lutetium

Lu

71

174.97

Magnesium

Mg

12

24.312

1.74

648.8

1090

Manganese

Mn

25

54.938

7.2

1244

1962

Mendelevium

Md

101

(256)

Mercury

Hg

80

200.59

13.594

-38.87

356.8

Molybdenum

Mo

42

95.94

10.2

2617

4612

Neodymium

Nd

60

144.24

7.07

1010

3127

Neon

Ne

10

20.183

.9002 e-3

-248.6

-246.08

Neptunium

Np

93

(237)

Nickel

Ni

28

58.71

8.9

1453

2732

Niobium

Nb

41

92.906

8.57

2468

4742

Nitrogen

N

7

14.0067

(N2)1.2505e-3

-219.86

-193.8

Nobelium

No

102

(254)

Osmium

Os

76

190.2

22.48

3045

5027

Oxygen

O

8

15.9994

(O2)1.429e-3

-218.4

-182.962

Palladium

Pd

46

106.4

12.02

1552

3140

Phosphorus

P

15

30.9738

2.34

590 (42 atm)

Platinum

Pt

78

195.09

21.45

1772

3827

Plutonium

Pu

94

(244)

19.74

639.5

3454

Polonium

Po

84

(210)

Potassium

K

19

39.102

.86

63.65

774

Praseodymium

Pr

59

140.907

6.78

931

3212

Promethium

Pm

61

(145)

Protactinium

Pa

91

(231)

Radium

Ra

88

(226)

5

700

1140

Radon

Rn

86

(222)

9.73 e-3

-71

-62

Rhenium

Re

75

186.2

20.5

3180

5630

Rhodium

Rh

45

102.905

12.4

1966

3727

Rubidium

Rb

37

85.4

1.532

39

6887

Ruthenium

Ru

44

101.07

12.3

2310

3900

Samarium

Sm

62

150.35

7.52

1077

1791

Scandium

Sc

21

44.956

2.989

1539

2832

Selenium

Se

34

78.96

4.81

217

685

Silicon

Si

14

28.086

2.32-2.34

1410

2355

Silver

Ag

47

107.87

10.49

961.93

2112

Sodium

Na

11

22.9898

.97

97.8

882.9

Strontium

Sr

38

87.62

2.6

769

1384

Sulphur

S

16

32.064

2.07

112.8

444.67

Tantalum

Ta

73

180.948

16.6

2996

5425

Technetium

Tc

43

(99)

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THERMODYNAMICS AND CHEMISTRY DATA – Page 7/14 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-3 – THERMODYNAMICS AND CHEMISTRY DATA

Tellurium

Te

52

127.6

6.25

449.5

990

Terbium Thallium

Tb

65

158.924

158.924

Tl

81

204.37

11.85

303.5

1457

Thorium

Th

90

232.038

11.7

1750

4790

Thulium

Tm

69

168.934

Tin

Sn

50

118.69

7.18

231.96

2270

Titanium

Ti

22

47.9

4.5

1660

3287

Tungsten Uranium

W

74

183.85

19.35

3410

5660

U

92

238.03

19.05

1132.3

3818

Vanadium

V

23

50.942

5.96

1890

3380

Xenon

Xe

54

131.3

5.887e-3

-111.9

-107.1

Ytterbium

Yb

70

173.04

Yttrium

Y

39

88.905

4.469

1523

3337

Zinc

Zn

30

65.37

7.14

419.58

907

Zirconium

Zr

40

91.22

6.49

1852

4377

Table 4: Properties of Typical Components CHEMICAL FORMULA

MOLECULAR WEIGHT (g)

VOLUMIC MASS (g/cm3)

Al2O3

101.9612

3.9655

BaO

153

BaSO4

136

C3S

228.323

C2S

172.244

C3A

270.199

C4AF

485.971

C2F

271.851

CaCO3

100.0892

2.93

FUSION TEMP. (C°)

EVAPORATION TEMP. (C°)

1339

898 (decomp) 2850

CaO

56.0794

3.25-3.8

2580

CaSO4

136.1376

2.61

>200

CaSO4.2H2O

172.1684

2.32

128 (-1.5H2O)

163 (-2H2O)

CO

28.0104

1.25e-3

-199

-191.5

CO2

44.0098

1.977e-3

-56.6

-78.5

Cr2O3

151.9902

5.21

2435

4000

FeO

71.8464

5.7

1420

Fe2O3

159.6922

Fe3O4

231.5386 1.00

0.00

100.0

H2O

18.0154

K2O

94.1994

K2SO4

174.2576

2.662

1069

1689

KCl

74.553

1.984

776

1500 (sub)

MgCO3

84.3142

MgO

40.3044

Mn2O3

157.8742

Na2O

61.979

Na2SO4

142.0372

2.68

884

NaCl

58.4428

2.165

801

P2O5

141.9446

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1413

THERMODYNAMICS AND CHEMISTRY DATA – Page 8/14 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-3 – THERMODYNAMICS AND CHEMISTRY DATA

SiO2

60.0848

2.26

1703

SO2

64.0588

2.927e-3

-72.7

-10

SO3

80.0582

1.97

16.83

44.8

TiO2

79.8988

3.84

1830-1850

2500-3000

Slag, blast furnace

2230

0.36

Table 5: Oxides and Other Definitions Formula Free CaO Ca(OH)2 2CaO.SiO2 3CaO.SiO2 3CaO.Al2O3

Short Form C2S C3S C3A

11 CaO.7 Al 2 O3 .CaX

C12 A7

Mineral Name or Technical Name Free lime Portlandite Dicalcium silicate, belite, larnite Tricalcium silicate, alite Tricalcium aluminate 12/7-calcium aluminate, mayenite

2 CAO.( Al 2 O3 .Fe2 O3 )

C 2 ( A, F )

Aluminate ferrite

2 CAO .Al 2 O3 .SiO2

C 2 AS

Gehlenite

CaSO4 CaSO4.½H2O CaSO4.2H2O CaCO3 2(CaO.SiO2).CaCO3 2(CaO.SiO2).CaSO4 K2SO4 Na2SO4 2CaSO4.K2SO4 (0) CaSO4.K2SO4.H2O 5CaSO4.K2SO4.H2O C3A.3CaSO4.32H2O

-

Calcium sulphate, anhydrite Hemihydrate, plaster Gypsum Calcium carbonate, calcite Spurrite Sulphate spurrite, sulpho-spurrite Potassium sulphate, arcanite Sodium sulphate, thenardite Calcium langbeinite Syngenite Gorgeyite Ettringite Alkali calcium sulphate

(K , Na )2 SO4 .2CaSO4

KCI K2O.Al2O3.2SiO2 Na2SO4.3K2SO4 FeS2 (0) =

-

KAS2

Potassium chloride, sylvine Kalsilite Aphthitalite Pyrite

Calcium langebeinite will react with the atmosphere to form K 2 Ca (SO4 )2 .H 2 O .

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THERMODYNAMICS AND CHEMISTRY DATA – Page 9/14 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-3 – THERMODYNAMICS AND CHEMISTRY DATA

2.2

Table 6: Correlation constants for calculation of Cp in kcal/kg.°K

Material O2

N2

H2

CO2

CO

SO2

NO H2O (vapor)

SiO2

Al2O3

Fe2O3

CaO

MgO

Temperature Limit

a

b

c

d

Cpm Top Range Limit

298 to 999°K

1.66341E-1

1.52333E-4

-5.93194E-8

1.14618E+3

0.2408

1000 to 3299°K

2.51162E-1

1.77998E-5

-6.07722E-10

-7.85447E+3

0.2736 0.2928

3300 to 6000°K

2.83126E-1

1.27044E-5

-9.60847E-10

-1.30952E+5

298 to 799°K

2.32210E-1

2.14938E-5

2.76050E-8

6.53840E+2

0.2553

800 to 2199°K

2.42450E-1

5.44079E-5

-1.05755E-8

-7.11335E+3

0.2838

2200 to 6000°K

3.20296E-1

1.05070E-7

2.16255E-10

-5.84722E+4

0.3079

298 to 999°K

3.71752E+0

-6.54182E-4

5.30928E-7

-1.34162E+4

3.4904

1000 to 2099°K

2.11603E+0

1.38511E-3

-2.23797E-7

3.03508E+5

3.7051

2100 to 6000°K

3.79977E+0

2.54376E-4

-8.12917E-9

-8.44345E+5

4.3278

298 to 799°K

1.49625E-1

2.42420E-4

-9.77776E-8

-1.01938E+3

0.2446

800 to 1799°K

2.60434E-1

6.27757E-5

-1.38167E-8

-1.43928E+4

0.2858

1800 to 3999°K

3.32286E-1

3.92911E-6

-9.13715E-11

-4.80845E+4

0.3158

4000 to 6000°K

3.58571E-1

-5.30873E-6

7.85626E-10

-1.07169E+5

0.3267

298 to 799°K

2.20543E-1

5.60021E-5

8.37651E-9

9.48925E+2

0.2575

800 to 2199°K

2.55445E-1

4.61682E-5

8.98815E-9

9.24077E+3

0.3259

2200 to 6000°K

3.17217E-1

1.74111E-6

3.30179E-11

4.64873E+4

0.3276

298 to 799°K

9.79544E-2

2.00701E-4

-9.82007E-8

-2.45323E+1

0.1749

800 to 2599°K

2.06945E-1

9.10368E-6

-1.25453E-9

-1.13897E+4

0.2044

2600 to 6000°K

2.17009E-1

2.34333E-6

-6.36079E-13

-1.79038E+4

0.2172

298 to 1199°K

1.81362E-1

1.28289E-4

-4.08850E-8

1.92938E+3

0.2566

1200 to 6000°K

2.92103E-1

3.55985E-6

-1.76784E-10

-2.64192E+4

0.2918

298 to 1199°K

3.75618E-1

1.68470E-4

4.13071E-10

1.72986E+3

0.5052

1200 to 2599°K

4.14544E-1

1.91743E-4

-2.78523E-8

-3.59274E+4

0.5997

2600 to 6000°K

7.48058E-1

1.29251E-5

-3.91557E-10

-4.02480E+5

0.7009

298 to 846°K

1.74571E-1

1.54435E-4

0.00000E+0

-3.84423E+3

0.2444

847 to 1078°K

2.34315E-1

3.99401E-5

0.00000E+0

0.00000E+0

1.3490

1079 to 1994°K

2.89399E-1

5.15389E-6

0.00000E+0

-1.64753E+4

0.7851

1995 to 2200°K

3.42819E-3

0.00000E+0

0.00000E+0

0.00000E+0

0.7015

298 to 599°K

1.58181E-1

3.16316E-4

-1.99797E-7

-4.40115E+3

0.2295

600 to 1599°K

2.70931E-1

3.61871E-5

-4.81287E-9

-9.75318E+3

0.2784

1600 to 2327°K

3.56484E-1

-2.66895E-5

7.55563E-9

-5.22846E+4

0.2929

2328 to 4000°K

3.92311E-1

0.00000E+0

0.00000E+0

0.00000E+0

0.3375

298 to 499°K

2.62773E-1

-2.71539E-4

3.64815E-7

-5.24040E+3

0.1754

500 to 799°K

1.93927E-1

1.68039E-5

5.79035E-8

-4.88997E+3

0.0898

800 to 1099°K

9.36550E+0

-1.24510E-2

4.70597E-6

-1.39500E+6

0.1423

1100 to 1599°K

2.27310E-1

-1.91821E-5

8.86418E-9

-7.56606E+3

0.1691

298 to 1399°K

2.11063E-1

2.41220E-5

-2.70785E-9

-3.42270E+3

0.2201

1400 to 3199°K

2.09137E-1

2.15260E-5

-7.61534E-10

0.00000E+0

0.2412

3200 to 4000°K

2.67475E-5

0.00000E+0

0.00000E+0

0.00000E+0

0.1894

298 to 899°K

2.56115E-1

8.67130E-5

-3.47648E-8

-5.23329E+3

0.2725

900 to 4000°K

2.92535E-1

1.98752E-5

-3.78829E-11

-8.79060E+3

0.3274

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THERMODYNAMICS AND CHEMISTRY DATA – Page 10/14 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-3 – THERMODYNAMICS AND CHEMISTRY DATA

Correlation constants for calculation of Cp in kcal/kg.°K (cont’d)

C p mean Top

Temperature Limit

a

b

c

d

K2O

298 to 499°K 500 to 799°K 800 to 2000°K

1.72260E-1 7.41409E-2 1.87709E-1

3.18402E-4 3.14076E-4 9.96111E-5

-3.33239E-7 -1.12686E-7 1.09170E-9

-2.24501E+3 9.04108E+3 -4.40135E+2

0.2276 0.2417 0.3025

Na2O

298 to 599°K 600 to 1023°K 1024 to 1405°K 1406 to 3500°K

1.04965E-1 3.12327E-1 3.18377E-1 4.03356E-1

5.91884E-4 8.43466E-5 4.76363E-5 0.00000E+0

-3.72410E-7 -2.18119E-8 0.00000E+0 0.00000E+0

1.61265E+3 -8.84785E+3 0.00000E+0 0.00000E+0

0.2988 0.3287 0.3447 0.3828

CaCO3

298 to 1200°K

2.49575E-1

5.23529E-5

0.00000E+0

-6.19443E+3

0.2692

MgCO3

298 to 599°K 600 to 799°K 800 to 1000°K

1.90758E-1 1.34623E-1 1.25484E-1

2.12990E-4 3.85987E-4 4.04459E-4

-1.43661E-10 -1.47945E-7 -1.53722E-7

-3.39798E+3 -1.38980E+3 -2.64523E+3

0.2628 0.2879 0.3081

K2SO4

298 to 599°K 600 to 856°K 857 to 1341°K 1342 to 3000°K

1.58125E-1 -7.13991E-1 -3.72465E-1 2.69999E-1

1.54102E-4 1.36132E-3 4.47300E-4 0.00000E+0

-3.18000E-8 -3.64171E-7 -2.64252E-10 0.00000E+0

-1.89092E+3 9.43877E+4 1.88203E+5 0.00000E+0

0.2074 0.2331 0.2556 0.2643

Na2SO4

298 to 521°K 522 to 979°K 980 to 1156°K 1157 to 3500°K

1.38524E-1 2.44072E-1 2.40087E-1 3.32160E-1

2.59737E-4 9.18685E-5 9.98029E-5 0.00000E+0

0.00000E+0 0.00000E+0 0.00000E+0 0.00000E+0

0.00000E+0 0.00000E+0 0.00000E+0 0.00000E+0

0.2417 0.2879 0.2997 0.3233

CaSO4 + ½ H2O + 2 H2O

298 to 1400°K 298 to 1000°K 298 to 1000°K

1.23255E-1 1.16776E-1 1.26844E-1

1.73351E-4 2.68688E-4 4.41399E-4

0.00000E+0 0.00000E+0 0.00000E+0

0.00000E+0 0.00000E+0 0.00000E+0

0.2683 0.2878 0.4078

KCl

298 to 699°K 700 to 1043°K 1044 to 2000°K

1.61827E-1 4.60282E-1 2.35949E-1

1.89934E-5 -5.38732E-4 0.00000E+0

2.40342E-8 3.19498E-7 0.00000E+0

-4.62219E+2 -2.63462E+4 0.00000E+0

0.1747 0.1862 0.2138

NaCl

298 to 1073°K 1074 to 1499°K 1500 to 2500°K

2.29593E-1 5.09687E-1 2.73785E-1

-5.18511E-5 -3.28475E-4 0.00000E+0

8.87734E-8 1.14261E-7 0.00000E+0

-1.37371E+3 0.00000E+0 0.00000E+0

0.2350 0.2499 0.2606

CaCl2

298 to 599°K 600 to 1044°K 1045 to 3000°K

1.66077E-1 1.95989E-1 2.20815E-1

6.89417E-6 -7.99550E-5 0.00000E+0

2.86392E-9 7.04763E-8 0.00000E+0

-1.02094E+3 -1.79242E+3 0.00000E+0

0.1634 0.1708 0.2067

CaF2

298 to 599°K 600 to 1423°K 1424 to 1690°K 1691 to 3500°K

3.29378E-1 1.74378E-1 3.30558E-1 3.05840E-1

-2.80694E-4 9.21586E-5 3.20184E-5 0.00000E+0

2.60932E-7 6.35505E-9 0.00000E+0 0.00000E+0

-5.23867E+3 3.01806E+3 0.00000E+0 0.00000E+0

0.2269 0.2635 0.2855 0.2969

C3S

298 to 2600°K

2.18324E-1

3.77524E-5

0.00000E+0

-4.44532E+3

0.2663

C2S

298 to 969°K 970 to 1709°K 1710 to 2403°K

2.02438E-1 1.86705E-1 2.84470E-1

5.65457E-5 6.39768E-5 8.22990E-5

0.00000E+0 0.00000E+0 0.00000E+0

-3.63425E+3 0.00000E+0 0.00000E+0

0.2238 0.2488 0.3156

C3A

298 to 2500°K

2.21910E-1

2.77202E-5

0.00000E+0

-4.36714E+3

0.2540

C4AF

298 to 2500°K

1.84143E-1

3.58039E-5

0.00000E+0

-1.79020E+2

0.2335

Material

Range Limit

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THERMODYNAMICS AND CHEMISTRY DATA – Page 11/14 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-3 – THERMODYNAMICS AND CHEMISTRY DATA

2.3

Table 7: Cp mean – reference 0ºC

kcal/kg°C O2 N2 H2 CO2 CO SO2 NO H2O Air SiO2 Al2O3 Fe2O3 CaCO3 Raw Slag CaO C3S C2S C3A C4AF Clinker

20°C 0.2190 0.2487 3.4073 0.1977 0.2489 0.1466 0.2385 0.4450 0.2418 0.1703 0.1768 0.1497 0.1870 0.1835 0.211 0.1749 0.1735 0.1731 0.1752 0.1920 0.1780

kcal/kg°C O2 N2 H2 CO2 CO SO2 NO H2O Air SiO2 Al2O3 Fe2O3 CaO C3S C2S C3A C4AF Clinker

1100°C 0.2493 0.2694 3.5490 0.2729 0.2927 0.1906 0.2604 0.5191 0.2647 0.2611 0.2720 0.1597 0.2197 0.2375 0.2377 0.2331 0.2131 0.2412

100°C 0.2206 0.2485 3.4304 0.2077 0.2488 0.1522 0.2374 0.4471 0.2420 0.1868 0.1962 0.1620 0.2057 0.2018 0.211 0.1850 0.1869 0.1851 0.1880 0.1940 0.1881 1200°C 0.2511 0.2715 3.5685 0.2764 0.2969 0.1924 0.2623 0.5269 0.2668 0.2634 0.2749 0.1643 0.2212 0.2402 0.2411 0.2353 0.2150 0.2464

200°C 0.2236 0.2492 3.4453 0.2183 0.2500 0.1587 0.2383 0.4519 0.2433 0.2025 0.2137 0.1729 0.2212 0.2172

300°C 0.2271 0.2506 3.4541 0.2275 0.2519 0.1644 0.2403 0.4580 0.2452 0.2154 0.2286 0.1347 0.2322 0.2277

400°C 0.2306 0.2525 3.4610 0.2356 0.2542 0.1695 0.2429 0.4648 0.2474 0.2267 0.2366 0.1066 0.2407 0.2359

500°C 0.2340 0.2547 3.4681 0.2428 0.2568 0.1739 0.2456 0.4721 0.2499 0.2372 0.2444 0.0923 0.2476 0.2431

600°C 0.2372 0.2572 3.4767 0.2493 0.2644 0.1777 0.2483 0.4796 0.2525 0.2455 0.2509 0.1093 0.2536 0.2496

700°C 0.2401 0.2597 3.4872 0.2550 0.2719 0.1810 0.2510 0.4873 0.2562 0.2491 0.2563 0.1286 0.2589 0.2549

800°C 0.2428 0.2623 3.5000 0.2602 0.2780 0.1839 0.2536 0.4951 0.2578 0.2524 0.2609 0.1401 0.2637 0.2596

900°C 0.2451 0.2648 3.5144 0.2649 0.2834 0.1864 0.2560 0.5031 0.2602 0.2557 0.2650 0.1480 0.2681 0.2639

1000°C 0.2473 0.2671 3.5308 0.2891 0.2882 0.1886 0.2583 0.5111 0.2625 0.2586 0.2687 0.1544

0.1932 0.1980 0.1954 0.1985 0.1961 0.1985

0.1989 0.2059 0.2032 0.2057 0.1982 0.2069

0.2032 0.2120 0.2094 0.2113 0.2001 0.2137

0.2057 0.2170 0.2148 0.2157 0.2020 0.2190

0.2096 0.2213 0.2196 0.2195 0.203 0.2233

0.2121 0.2251 0.2240 0.2228 0.2058 0.2289

0.2143 0.2286 0.2275 0.2257 0.2076 0.2302

0.2162 0.2318 0.2309 0.2283 0.2095 0.2334

0.2180 0.2347 0.2344 0.2308 0.2113 0.2370

1300°C 0.2528 0.2735 3.5892 0.2795 0.3011 0.1939 0.2641 0.5346 0.2687 0.2655 0.2777 0.1682 0.2227 0.2428 0.2444 0.2373 0.2168 0.2529

1400°C 0.2545 0.2754 3.6107 0.2825 0.3051 0.1954 0.2668 0.5420 0.2706 0.2673 0.2802 0.1717 0.2241 0.2453 0.2477 0.2393 0.2186 0.2610

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

1500°C 0.2560 0.2772 3.6327 0.2852 0.3091 0.1967 0.2673 0.5492 0.2723 0.2690 0.2826 0.1748 0.2254 0.2478 0.2565 0.2413 0.2204 0.2711

1600°C 0.2574 0.2789 3.6549 0.2876 0.3130 0.1979 0.2687 0.5562 0.2739 0.2706 0.2847 0.1776 0.2267 0.2502 0.2676 0.2431 0.2222 0.2836

1700°K 0.2588 0.2805 3.6772 0.2899 0.3170 0.1900 0.2701 0.5629 0.2755 0.2720 0.2867 0.1801 0.2279 0.2525 0.2779 0.2449 0.2240 0.2987

1800°C 0.2602 0.2820 3.6994 0.2920 0.3209 0.2000 0.2713 0.5694 0.2770 0.2605 0.2886 0.1825 0.2291 0.2548 0.2875 0.2467 0.2258 0.3167

1900°C 0.2614 0.2834 3.7213 0.2940 0.3249 0.2010 0.2724 0.5757 0.2783 0.2469 0.2904 0.1847 0.2303 0.2570 0.2966 0.2485 0.2276 0.3382

2000°C 0.2627 0.2847 3.7430 0.2958 0.3261 0.2019 0.2735 0.5817 0.2796 0.2348 0.2921 0.1868 0.2314 0.2592 0.3051 0.2502 0.2294 0.3632

THERMODYNAMICS AND CHEMISTRY DATA – Page 12/14 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-3 – THERMODYNAMICS AND CHEMISTRY DATA

3.

Psychrometric Chart

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THERMODYNAMICS AND CHEMISTRY DATA – Page 13/14 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-3 – THERMODYNAMICS AND CHEMISTRY DATA

My notes:

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THERMODYNAMICS AND CHEMISTRY DATA – Page 14/14 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-4 – UNIT CONVERSION

9-4. Unit Conversion

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UNIT CONVERSION – Page 1/10 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-4 – UNIT CONVERSION

Table of Contents 1.

Mass .............................................................................................................3

2.

Length ..........................................................................................................3

3.

Area ..............................................................................................................4

4.

Volume .........................................................................................................4

5.

Velocity.........................................................................................................5

6.

Flow Rate .....................................................................................................5

7.

Concentration ..............................................................................................5 7.1

General Concentration Units .......................................................................... 5

7.2

Gas Concentration.......................................................................................... 6

8.

Pressure .......................................................................................................7

9.

Heat, Work ...................................................................................................7

10.

Calorific Value .............................................................................................8 10.1 Calorific Value (Gas Basis)............................................................................. 8 10.2 Liquid Calorific Value ...................................................................................... 8 10.3 Calorific Value (Mass Basis)........................................................................... 8

11.

Specific Heat................................................................................................9 11.1 Specific Heat (Gas Basis)............................................................................... 9 11.2 Specific Heat (Mass Basis)............................................................................. 9

12.

Force ............................................................................................................9

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UNIT CONVERSION – Page 2/10 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-4 – UNIT CONVERSION

1.

Mass

Time:

[]

The fundamental unit of time t is the second s whose definition is based on an invariant property of cesium 133.

Mass: International System of Unit ISU : [kg]. 1 kg is the mass of a cylinder of platinum alloy kept at Sèvres, France. MultiplyÈ to obtain Æ

kg

g

t

lb

Short ton

troy

grain

ounce

ounce

hundred weight

sh hundred weight

kg

1

1000

0.001

2.2046

1.102E-03

15432

32.151

35.274

0.0197

0.022

g

0.0001

1

1E-06

0.0022

1.1E-06

15.4323

0.0322

0.0353

1.97E-05

2.20E-05

T

1000

1E+06

1

2204.6

1.10231

1.5E+07

32151

3.5274

19.684

22.046

lb

0.4536

453.59

0.0005

1

0.0005

7000

14.583

16

0.0089

001

Short ton

907.19

907185

0.9072

2000

1

1.40E+07

29167

32000

17.857

20

grain

6.48E-05

0.0648

6E-08

0.0001

171E-08

1

0.0021

0.0023

1.28E-06

1.43E-06

troy ounce

0.0311

31.104

3E-05

0.0686

3.4E-05

480.00

1

1.0971

0.0006

0.0007

ounce

0.0283

28.35

3E-05

0.0625

3.1E-05

437.499

0.9115

1

0.0006

0.0006

hundred weight

50.802

50802

0.0508

112

0.056

783994

1633.3

1792

1

1.12

sh hundred weight

45.359

45359

0.0454

100

0.05

699996

1458.3

1600

0.8929

1

2.

Length

(ISU : [m] ; 1 meter = wavelength of orange-red light) MultiplyÈ to obtain Æ m

m 1

cm

km

100

0.001

in

ft

yd

39.37008

3.28084

1.093613

miles

miles

(stat)

(naut)

0.000621

0.00054

cm

0.01

1

0.00001

0.393701

0.032808

0.010936

6.21E-06

5.4E-06

km

1.00E+03

100000

1

39370.08

3280.84

1093.613

0.621371

0.539665

in

0.0254

2.54

2.54E-05

1

0.83333

0.027778

1.58E-05

1.37E-05

ft

0.3048

30.48

0.000305

12

1

0.333333

0.000189

0.000164

yd

0.9144

91.44

0.000914

36

3

1

0.000568

0.000493

miles (stat)

1609.344

160934.4

1.609344

63360

5280

1760

1

0.868507

miles (naut)

1853

185300

1.853

72952.76

6079.396

2026.465

1.151401

1

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

UNIT CONVERSION – Page 3/10 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-4 – UNIT CONVERSION

3.

Area

(ISU : [m 2 ] ) m2

cm2

km2

hectare

in2

ft2

yd2

miles2

acre (US)

m2

1

10000

1E-06

0.0001

1550.003

10.7639

1.19603

3.86E-07

0.00025

cm2

0.0001

1

1E-10

1E-08

0.155

0.00108

0.00012

386E-11

2.47E-08

km2

1.00E+06

1.00E+10

1

100

1.55E+09

1.1E+07

1196029

0.3861

247.105

hectare

1.00E+04

1.00E+08

0.01

1

1.55E+07

107639

11960.3

0.00386

2.47105

in2

0.00065

6.4516

6.5E-10

6.5E-08

1

0.00694

0.00077

2.49E-10

1.59E-07

ft2

0.0929

929.03

9.3E-08

9.3E-06

143.9999

1

0.11111

3.59E-08

2.30E-05

yd2

0.8361

8361

8.4E-07

8.4E-05

1295.958

8.99971

1

3.23E-07

0.00021

miles2

2590000

2.59E+10

2.59

259

4.015E+09

2.79E+07

3097716

1

640.003

acre (US)

4046.85

4.05E+07

0.00405

0.40469

6272637

43560

4840

0/00156

1

M3

cm3

MultiplyÈ to obtain Æ

4.

Volume

(ISU : [m 3 ] )

MultiplyÈ to obtain Æ

Litre

inch3

ft3

US gallon

US

UK gallon

yd3

fION

barrel m3

1

1000000

1000

61024

35.3147

264.171

6.28978

219.974

1.30794

33783.8

cm3

1E-06

1

0.001

0.06102

3.53E-05

0.00026

6.29E-06

0.00022

1.31E-06

0.03378

Litre

0.001

1000

1

61.024

0.03531

0.26417

0.00629

0.21997

0.00131

33.7838

inch3

1.6E-05

16.387

0.01639

1

0.00058

0.00433

0.0001

0.0036

2.14E-05

0.55361

ft3

0.02832

28316.8

28.3168

1728

1

7.48047

0.17811

6.22895

0.03704

956.649

US gallon

0.00379

3785.43

3.78543

231.002

0.13368

1

0.02381

0.83269

0.00495

127.886

US barrel

0.15899

158988

158.988

9702.08

5.61462

42

1

34.9732

0.20795

5371.22

UK gallon

0.00455

4546

4.546

277.415

0.16054

1.20092

0.02859

1

0.00595

153.581

yd3

0.76456

764560

764.56

46656.5

27.0002

201.974

4.80892

168.183

1

25829.7

fION

2.96E-05

29.6

0.0296

1.80631

0.00105

0.00782

0.00019

0.00651

3.87E-05

1

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

UNIT CONVERSION – Page 4/10 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-4 – UNIT CONVERSION

5.

Velocity

(ISU : [m 3 .s −1 ] )

MultiplyÈ to obtain Æ m/s

m/s

m/s

km/h

ft/min

miles/h

knots

ft/s

1

60

3.6

196.8504

2.237136

1.942795

3.2808

m/min

0.016667

1

0.06

3.28084

0.037286

0.03238

0.05468

km/h

0.277778

16.66667

1

54.68066

0.621427

0.539665

0.911333

ft/min

0.00508

0.3048

0.018288

1

0.011365

0.009869

0.016666

0.447

26.82

1.6092

88

1

0.86843

1.466518

knots

0.514722

30.88333

1.853

101.3233

1.151504

1

1.688701

ft/s

0.304804

18.28822

1.097293

60.00073

0.681887

0.592171

1

m3/s

m3/min

m3/h

l/m

ft3/s

ft3/m

gal US/min

1

60

3600

60000

35.31472

2118.883

15850.25

m3/min

0.016667

1

60

1000

0.588579

35.31472

264.1708

m3/h

0.000278

0.016667

1

16.66667

0.00981

0.588579

4.402846

miles/h

6.

Flow Rate

(ISU : [m 3 .s −1 ] )

MultiplyÈ to obtain Æ m3/s

l/m

1.67E-05

0.001

0.06

1

0.000589

0.035315

0.264171

ft3/s

0.028317

1.699008

101.9405

1699.008

1

60

448.8283

ft3/m

0.000472

0.028317

1.699008

28.3168

0.016667

1

7.480471

gal US/min

6.31E-05

0.003785

0.227126

3.78543

0.002228

0.133681

1

European standard conditions: dry gas @ 273K, 101 kPa, 10%O2

7. 7.1

Concentration General Concentration Units

(ISU : [kg .m −3 ] )

MultiplyÈ to obtain Æ

kg/m3

g/cm3

g/m3

mg/l

grain/UKgal

grain/ft3

lb/ft3

lb/UKgal

kg/m3

1

0.001

1000

1000

0.07015673

436.9961

0.062428

0.010022

g/cm3

1000

1

1000000

1000028

70.15673

436996.09

62.42782

10.02241

g/m3

0.001

0.000001

1

1.000028

0.070157

0.4369961

6.24E-05

1E-05

mg/l

0.001

1E-06

0.999972

1

0.070155

0.4369839

6.24E-05

1E-05

grain/UKgal

14.254

0.0143

14.2538

14.2542

1

6.228855

8.9E-4

0.000143

grain/ft3

2.29E-3

2.29E-06

2.2884

2.2884

0.1605

1

1.43E-04

2.29E-05

lb/ft3

16.0185

0.016019

16018.5

16018.95

1123.806

7000.022

1

0.160544

lb/UKgal

99.7764

0.099776

99776.4

99779.19

6999.986

43601.90

6.228823

1

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

UNIT CONVERSION – Page 5/10 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-4 – UNIT CONVERSION

7.2

Gas Concentration Multiply ppm by figures below for mg/m3 Molecula r Weight

Density kg/Nm3

mg/Nm3 0°C

mg/m3 20°C

mg/m3 25°C

Nitrogen

N2

28.013

1.250

1.250

1.165

1.145

Oxygen

O2

31.999

1.428

1.428

1.330

1.308

28.963

1.292

1.292

1.204

1.184

Air (dry) Hydrogen Chloride

HCl

36.461

1.627

1.627

1.516

1.490

Hydrogen Sulfide

H2S

34.080

1.520

1.520

1.417

1.393

Ammonia

NH3

17.031

0.760

0.760

0.708

0.696

Nitrogen Monoxide

NO

30.006

1.339

1.339

1.247

1.226

Nitrogen Dioxide

NO2

46.006

2.053

2.053

1.913

1.880

Nitrous Oxide

N2O

44.013

1.964

1.964

1.830

1.799

Carbon Monoxide

CO

28.011

1.250

1.250

1.164

1.145

Carbon Dioxide

CO2

44.010

1.964

1.964

1.830

1.799

CH4

16.043

0.716

0.716

0.667

0.656

C3H8

44.097

1.967

1.967

1.833

1.802

C6H6

78.115

3.485

3.485

3.247

3.193

SO2

64.063

2.858

2.858

2.663

2.619

Methane Propane Benzene Sulfur Dioxide

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

UNIT CONVERSION – Page 6/10 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-4 – UNIT CONVERSION

8.

Pressure

(ISU : 1[Pa] = 1[N .m −2 ] )

MultiplyÈ to obtain Æ

kgf/cm2

mbar

Pascal

mmWG

mmHG

PSI

hWG

inHG

ATA

ATU

14.223

393.7

28.959

0.96784

74.6269

(torr) kgf/cm2

1

mbar

980.66

98066

10000

735.56

0.001

1

100

10.197

0.7501

0.0145

0.4015

0.0295

0.00099

0.0761

Pascal

1.020E-05

0.01

1

0.102

0.0075

0.0001

0.004

0.0003

9.87E-06

0.00076

mmWG

1.00E-04

0.0981

9.8065

1

0.0736

0.0014

0.0394

0.0029

9.68E-05

0.00746

mmHG

0.0014

1.3332

133.32

13.595

1

0.0193

0.5352

0.0394

0.00132

0.10146

PSI

0.0703

68.947

6894.7

703.08

51.715

1

27.68

2.036

0.06805

5.24679

inWG

0.0025

2.4909

249.09

25.4

1.8683

0.0361

1

0.0736

0.00246

0.18955

inHG

0.0345

33.864

3386.4

345.32

25.4

0.4912

13.595

1

0.03342

2.57699

Atmosphere

1.0332

1013.2

101325

10332

760

14.696

406.78

29.921

1

77.1067

ATU

0.0134

13.141

1314.1

134

9.8566

0.1906

5.2756

0.3881

0.01297

1

1 Newton/m2 = .01 millibar = 10 A/cm2

1kgf/m2 = 1 mmWG

1 Pieze = 10 millibar = 10000 dyne/cm2

9.

Heat, Work

(ISU : 1[J ] = 1[N .m]; 1 cal = 4 ,1868[J ])

used to be defined as the quantity of heat, which must be transferred to one gram of water to raise its temperature by one centigrade). MultiplyÈ obtain Æ Joule Calorie kJ kcal BTU

to

Joule

Calorie

kJ

kcal

1

0.2388

0.001

0.0002

4.1868

1

0.0042

0.001

BTU

Thermie

Therm

kgfm

ft-poundf

kWh

hph

0.0009 2.39E-07

9.48E-09

0.102

0.7376

2.78E-07

3.73E-07

0.004

1.00E-06

3.97E-08

0.4269

3.088

1.16E-06

1.56E-06

1000

238.85

1

0.2388

0.9478

0.0002

948E-06

101.97

737.56

0.0003

0.0004

4186.8

1000

4.1868

1

3.9683

0.001

3.97E-05

426.93

3088

0.0012

0.0016

1055.1

252

1.0551

0.252

1

0.0003

1E-05

107.59

778.17

0.0003

0.0004

Thernie

419E+06 1.00E+06

4186.8

1000

3968.3

1

0.0397

426935

3.09E+06

1.163

1.5596

Therm

1.06E+08 2.52E+07 105506

25200

100000

25.2

1

1.08E+07

7.78E+07

29.307

39.302

kgfm

9.8067

2.3423

0.0098

0.0023

0.0093 2.34E-06

9.29E-08

1

7.233

2.72E-06

3.65E-06

ft-poundf

1.3558

0.3238

0.0014

0.0003

0.0013 3.24E-07

1.29E-08

0.1383

1

3.77E-07

5.05E-07

kWh

3.60E+06

859845

3600

859.85

3412.1

0.8598

0.0341

367098

2.66E+06

1

1.341

hph

2.68E+06

641187

2684.5

641.19

2544.4

0.6412

0.0254

273745

1.98E+06

0.7457

1

1 Joule = 1 Newton-metre

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UNIT CONVERSION – Page 7/10 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-4 – UNIT CONVERSION

10. Calorific Value 10.1

[

Calorific Value (Gas Basis)

(ISU: J .m

−3

]

at 273.15oK and 101375 Pa) To Obtain J/m3

kcal/m3

kcal/m3

0°C

0°C

15°C

760 mmHg

760 mm Hg

760 mmHg

BTU/ft3

1

0.238846

0.226406

0.025018

kcal/m3

4.1868

1

0.947917

0.104745

kcal/m3

4.416844

1.054945

1

0.1105

BTU/ft3

39.97138

9.547

9.04976

1

Multiply By

J/m3

10.2

Liquid Calorific Value

[

]

(ISU: J .m −3 ) To Obtain Multiply By

Joule/m3

Joule/1

kcal/1

Therm/UK gal

BTU/US gal

1

0.001

0.000239

4.31E-08

3.59E-06

Joule/m3 Joule/1 kcal/1 Therm/UK gal BTU/US gal

10.3

1000

1

0.238846

4.31E-05

0.003588

4186.8

4.1868

1

0.00018

0.015022

23208688

23208.69

5543.3

1

83.27002

278716

278.716

66.57018

0.012009

1

Calorific Value (Mass Basis)

[

]

(ISU: J .kg −1 ) To Obtain Multiply By J/kg J/g kcal/kg

J/kg

J/g

kcal/kg

BTU/lb

BTU/st

Therm/t

1

0.001

0.000239

0.00043

0.859158

9.63E-06

1000

1

0.238846

0.429923

859.1579

0.00963

4186.8

4.1868

1

1.8

3597.122

0.04032

BTU/lb

2326

2.326

0.555556

1

1998.401

0.0224

BTU/st

1.16393

0.001164

0.000278

0.0005

1

1.12E-05

Therm/t

103839

103.839

24.80152

44.64273

89214.1

1

© Copyright 1990-2010, Lafarge SA. All rights reserved. INTERNAL USE ONLY

UNIT CONVERSION – Page 8/10 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-4 – UNIT CONVERSION

11. Specific Heat 11.1

Specific Heat (Gas Basis)

[

] [

]

(ISU: J /( m 3 .o K ) = J / m 3 .o C To Obtain J/m3*°C

kJ/m3*°C

kcal/m3*°C

BTU/ft3*°F

J/m3*°C

1

0.001

0.00023885

1.4911E-05

kJ/m3*°C

1000

1

0.2388459

0.01491066

kcal/m3*°C

4186.8

4.1868

1

0.06242796

BTU/ft3*°F

67066.1

67.0661

16.0184628

1

Multiply By

11.2

Specific Heat (Mass Basis)

[

][

]

(ISU: J /( kg .o K ) = J /( kg .o C ) To Obtain Multiply By

J/kg*°C

kJ/kg*°C

kcal/kg*°C

BTU/lb*°F

J/kg*°C

1

0.001

0.00023885

0.00023885

kJ/kg*°C

1000

1

0.2388459

0.2388459

kcal/kg*°C

4186.8

4.1868

1

1

BTU/lb*°F

4186.8

4.1868

1

1

12. Force

[

(ISU : kg .m.s

−2

] = 1 [N ] Newton

)

1 Newton is the force which when applied to a one-kilogram mass will produce an acceleration of one meter per second). Newton

Newton

dyne

gf

sthene

poundal

poundforce

1

100000

101.9716

1.00E-03

7.233011

0.224809

dyne

0.00001

1

0.00102

1E-08

7.23E-05

2.25E-06

gf

0.009807

980.665

1

9.81E-06

0.070932

0.002205

sthene

1000

1E+08

101971.6

1

7233.011

224.809

poundal

0.138255

13825.5

14.09809

0.000138

1

0.031081

poundforce

4.44822

444822

453.5922

0.004448

32.17403

1

Temperature • The Celsius scale is defined as the ice point (freezing point of water salined with air at standard atmospheric pressure = 1 atm = 101 325 Pa) is 0oC and the steam point (boiling point of pure water at 1 atm = 101325 Pa) = 100oC. • Fahrenheit: (oF)=32+1.8*( oC). • Kelvin: (oK)=( oC)+273.15. • Rankine: (oR)=( oF)+459.67.

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UNIT CONVERSION – Page 9/10 Version September 2010

CEMENT PROCESS ENGINEERING VADE-MECUM CHAPTER 9-4 – UNIT CONVERSION

My notes:

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UNIT CONVERSION – Page 10/10 Version September 2010