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Holcim Standard Design Criteria and Technical Data Sheets

Holcim Standard Design Criteria and Technical Data Sheets Standard Design Criteria describe the technical requirements for mechanical and electrical equipment as well as for civil and structural steel works. They have to be applied to all CAPEX projects with possible exceptions to chapters or paragraphs related to local conditions and/or regulations, as applicable.

Standard Design Criteria: Are based on proven technologies, practical experiences and best practices gathered from

many Group plants and other sources. Have been elaborated with a view towards high equipment efficiency (OEE), high reliability

(MTBF) and low maintenance requirements. Facilitate preparation of the technical parts of a Tender Document. Will be recognized by tenderers as Holcim Standard thus also ease their efforts in preparing

quotations.

Technical Data Sheets: Summarize important data of the equipment. Serve as templates for the tenderers to fill in the requested data. Serve for efficient evaluation of the offered equipment. Will eventually become an integrated part of a contract.

Holcim Standard Design Criteria and Technical Data Sheets How to use the Design Criteria and Data Sheets for your project? Read the Introduction to become acquainted with the concept of Standard Design

Criteria and Technical Data Sheets. Select the relevant parts of Design Criteria for your project  Use the " Fetch" mode for reading documents  Use the "Download" mode for inserting selected parts of Design Criteria in

your Tender Document. Select the relevant folder of Data Sheets and find access by means of the "Browse"

button.

Do not modify text or technical data specified in the Standards other than parts

related to local conditions. Standards have been approved by HGRS specialists and are based on practical experiences. In case of uncertainty or need for additional information and/or clarification please

contact the below listed document owners.

Holcim Standard Design Criteria and Technical Data Sheets INTRODUCTION - DESIGN CRITERIA AND DATA SHEETS PART IV 1 BASIC REQUIREMENTS PART IV 2A STANDARD MECHANICAL EQUIPMENT PART IV 2B MAIN MECHANICAL PROCESS EQUIPMENT PART IV 3 PROCESS CONTROL AND ELECTRICAL EQUIPMENT PART IV 4 CIVIL WORKS Data Sheets for Standard Mechanical Equipment Data Sheets for Main Mechanical Process Equipment Data sheets for Process Control and Electrical Equipment Data sheets for Civil Works Evaluation Data Sheets for Standard Mechanical Equipment Evaluation Data Sheets for Main Mechanical Process Equipment Evaluation Data sheets for Process Control and Electrical Equipment

Holcim Standard Design Criteria

Dust Collector Design Basic

Content • • • • •

Technology of dust collecting systems Design guidelines Design features Cleaning control Examples

Objectives • To point out and explain most important criteria in the field of dust collector systems design • To provide basic concepts around dust collector technology • To show examples, where design guidelines were applied

Technology – Terminology • Terminology of pulse-jet dust collector

1

Dust loaden air

11

Diaphragm pulse valve

2

Diffuser

12

Pulse control timer

3

Bag cage

13

Rotary valve

4

Clean air outlet (Plenum)

14

Differential pressure gauge

5

Tube sheet

15

Closing valve

6

Filter bag

16

Compressed air bin

7

Venturi

17

Regulation damper valve

8

Locking ring (or snap band fixation)

18

Fan

9

Blowpipe

19

10

Header (compressed air tank)

Purge unit with hand reducer and filter set

Technology – Cleaning Principles • Various cleaning principles used for bag filters

Technology – Bag Fixation Systems • Types of filter bag fixations (jet-pulse)

Snap band Filter bag

Fig. 1: Filter bag fixation by snapband

Fig. 2: Filter bag fixation by mechanical clamp

Filter Media (1/4) – Fabrics • Filter cloth fabrication  

Needle felt Woven felt

• Differences of filter bags without and with membrane treatment

Fig. 1: Filter bag without membrane

Fig. 2: Filter bag with membrane

Filter Media (2/4) – Fabrics and Trademarks Natural

Fabric, Trademark

Chemical Classification

DIN 60 001

Tensile strength N/mm2

Cotton

max. Operating Temperature [°C] long time short time

Acide Resist.

Alkali Resist.

Abrasion Resist.

Moist Heat Resist.

Price Rating

Density [g/m2]

Cellulose

(CO)

410-670

70-90

120

5

3

2

3-4

$

150-400

Wool

Keratin (protein)

(WO)

120-230

90

120

3-4

4

3-4

3-4

$$

400-600

Acrilan, AC/AC

Polyacrylnitrile

(PAN)

200-530

100-110

100-120

3

3-4

3-4

1

$$

500-600

(PAN)

200-530

110-120

120-140

2-3

3-4

3-4

1

$$

500-600

(PP)

260-640

90-100

100-120

1-2

1-2

1-2

1-2

$

550

(PES)

560-820

130-150

150-160

3-4

3-4

2

5

$

400-600

Fibers

- copolymer Dralon,

Synthetic Organic Fibers

Orlon,

Zefran, Polyacrylnitrile

Dolanit

- homopolymer

Polypropylene, Meraklon

Polypropylene

Trevira, Dacron, Terylene, Polyester Tergal, Vestan, Kodel

(dry)

Nylon, Perlon

Polyamide (alipahtic)

Nomex, Conex, Trol

Polyamide

(aromatic)

(Aramide) Teflon Ryton,

Synthetic Anorganic

Polytetra-Fluorethylene PPS,

Rastex, Polyphenylene-

Procon

Sulfid (PPS)

P 84

Polyimid (PI)

Glass, Fiberglass

Glass

Stone Wool

Mineral

Various Steels

Metals

PA

370-850

90-110

100-120

4

2

1-2

3-4

$

300

570-690

180-210

200-240

good in

Excellent at

1-2

3-4

$$$$

500-600

weak acids

low temp. 1

$$$$$$$

750-940

(AR) (PTFE)

380

260

280

1-2

1-2

3-4

1000-1200

180 max.

200 max.

1

1

2-3

$$$$$$

500-800

5%O2

15% O2

240-260

280

1-2

1-2

4-5

$$$$$$

550

3-4

4

$$$

300-400

850-900

1500-2500 230-270 350 3-4 Legend: 1: excellent 2: very good 120-260 300-350 3-4 500-750

up to 600

1

3: good 3-4 1

3

4: fair 5: poor 1

Filter Media (3/4) – Surface Treatment

Filter Media (4/4) – Surface Treatment

Design Guidelines (1/5) – General • Maximum 6 (8) dust sources to be connected to one filter • The following maximum air to cloth ratios based on a bag length of 4.5 m shall apply:  

1.5 m3/(m2min) for general dedusting 1.2 m3/(m2min) for slag, coal, bypass, fly ash and clinker dust

• Can velocity (theoretically calculated raw gas velocity between the filter bags in the area of the bag bottom) valid independently of raw gas inlet design shall be maximum 1.3 m/s • The hopper valley (corner) angles should not be less than 55°

Design Guidelines (2/5) – Fabrics • Filter cloth: 







General application (dry gas) up to 120 °C (long time operation), needle felt fabric made from high quality Polyester fibers are used. Application in drying/grinding (humid gas) up to 120 °C (long time operation), Polyacrylnitrile or similar fiber cloth is recommended. Application for temperatures above 120 °C, Polyamide (Nomex), Polyphenylene, Glass-fiber, Teflon/graphite coated or similar. Pleated filter bags and star bags shall not be used (except for electrical room pressurization and only with engineer’s approval)

Holcim Indonesia Transport and Dedusting Workshop

Design Guidelines (3/5) – Duct Work • Dedusting Ducts 

Up- and downward sloping a minimum slope of:    





 



60° for limestone, slag, cement 50° (45°) for clinker 70° for coal Horizontal ducts are not accepted

The maximum velocity in these runs shall be 18 m/s, for slag/clinker 16 m/s For fan discharge duct, the velocity preferably shall be in the range of 15 to 20 m/s Minimum duct diameter shall be 133 mm (outside) Velocity (v1) at dedusting hood entries shall not exceed 1.5 m/s Minimum duct and hood wall thickness to be 3 mm (1/8”)

Design Guidelines (4/5) – Duct Work

Recommended elbow

Design Guidelines (1/5) – Venting Air Volumes • Recommended venting air volume

Design Features (1/4) – Casing and Deflector • Raw gas inlet design (side inlet into dust collector) Typical design

Recommended

Preferred deflector plate design

• Raw gas inlet design (top inlet into dust collector)

Design Features (2/4) – Hoppers • Problem solving for blocked dust collector hopper 700

440

700

50

250

350

650 1250

250

Fig. 3: Example dimensioning of dust hopper and screw Fig. 1: Blockages may occur (sticky dust) due to small opening of the dust hopper discharge

Fig. 2: Possible solution, dust hopper with vertical side walls

Design Features (3/4) – General Hooding for Belt conveyor

Hooding for Airslide

Skirting for apron conveyor Dust curtain

Design Features (4/4) – Venting Hood

Cleaning Control (1/2) – Cycle • Bag cleaning cycle guidelines: 



 





The bag cleaning shall be controlled by timer and differential pressure measurement across the bag filter Cleaning pressure: max. 5.8 - 6.0 bar for polyester bags, max. 5.0 - 5.2 bar for polyester bags with membrane Pulse duration: 0.1 sec Pulse frequency: between two pulses 5 to 30 sec or more, depending the differential pressure over tube sheet Cycle time: each solenoid valve should pulse within 120 to 240 sec (max) Differential pressure adjustment: lower set point 10 mbar, upper set point 12.5 mbar

Cleaning Control (1/2) – Sequence • Recommended cleaning sequence Typical cleaning sequence

Recommended cleaning sequence

• Example of recommended cleaning sequence for a dust collector with 17 bag-rows and 10 timer positions:

Examples (1/3) – Drawing

Fig. 1: Example of properly designed dedusting system for hot clinker (>150°C) application

Examples (2/3) – Installations

Dust Collectors

Packing Area

Proper designed ductwork, with correct inclination and elbows Proper designed dust collector system with preseparator chamber due to hot clinker

Proper designed spillage collection equipment below packer including settling chamber for the main venting duct

Examples (3/3) – Installation • Dust confinement at crusher hopper by dust curtain

Holcim Standard Design Criteria

Dust Collector – Case Study

Objectives • To show the procedure on how do design a dust collecting system    

Definition of required venting air volume at each pick-up point Calculation of ductwork diameter Filtration surface calculation Fan specification

Transport System to Be Vented • Where is venting required in the system shown below?

Step 1: Determination of Pick-up Points

3 5

4

6

7

1 2

Step 2: Determination of Venting Air Volume on each Pick-up Point

3 5

4

6

7

1 2

• Material: Cement • System Capacity: 300 t/h • Airslide width: 500 mm, total air volume 900 m3/h • Bucket elevator: Belt type, bucket width 800 mm • Belt Conveyor: Belt width 1000 mm • Point 7: It is required 3’000 m3/h

Step 3: Calculation of Ductwork Diameter  What is the recommend

gas velocity in the duct for cement dust?

9 12

10 11

3

5

4

 What are the diameters

on each pick-up point (1-7)?

6

 What are the diameters

8 7

on remain sections of the ductwork system (8-12)?

1 2

Remark: The calculated diameters do not match to the standard sizes. For construction purposes take the next higher standard size for each calculated diameter

Step 4: Calculation of Filtration Area • What is the filtration area required to handle 14’850 m3/h? (refer to page B1/12 of the TDS Manual) • How many filter bags are required? (The plant where this unit will be installed has standard size of filter bags of Ø 140 mm x 3.2 m length – 1.42 m2)

3 5

4

6

7

1 2

Step 4: Calculation of Filtration Area (Solution) • What is the filtration area required to handle 14’850 m3/h? (refer to page B1/12 of the TDS Manual) 



Recommended A/C Ratio is 1.5 m3/m2*min (or 90 m3/m2*h) for cement dust Filtration area (A) is:

3 A = Fan Capacity => A = _14’850 [m /h ]_ A/C Ration 90 [m3/m2*h]

3 5

4

6

7

• How many filter bags are required? (The plant where this unit will be installed has standard size of filter bags of Ø 140 mm X 3.2 m length – 1.42 m2) 

1 2

A = 165 m2

Total Filtration Area / one bag filter area = 117 bags

Step 5: Fan Specification • What is the fan capacity for venting of the system? (refer to page B1/20 of the TDS Manual) • What should be the minimum fan static pressure? • What should be the fan speed?

3 5

4

6

7

1 2

Step 5: Fan Specification (Solution) • The required venting air for the system is 14’850 m3/h  

Consider ca. 15% safety margin Therefore, the fan capacity is: Required Volume + 15% of required volume => 14’850 [m3/h] + 2’250 [m3/h] = 17’100 [m3/h]

• Minimum static pressure should be 28 mbar • The fan speed should not exceed 1’800 rpm

3 5

4

6

7

1 2

Holcim Standard Design Criteria

Belt Conveyor Design Basic

Belt Conveyor – Terminolgy and applications

Belt conveyor is used to transfer bulk materials (cement, clinker, gypsum, coal, raw meal, etc). Motor Drive & Reducer Gear

All belt conveyors shall be designed in accordance with DIN, CEMA or ANSI standards.

Design Guideline (1/6) • Belts shall be endlessly vulcanized • Trough angles  shall not be less than 30° • Belt speed:  The maximum belt speed plant internal shall not exceed 2.0 m/s  Conveyors handling dry fine material (i.e. raw meal, cement) shall not exceed

• • • •

1.25 m/s  Belt speed for conveyors less than 50 meters in length shall not exceed 1.5 m/s  Conveyors longer than 500 m (overland) can operate faster than 2.0 m/s  Overland conveyors may operate at velocities in excess of 2.0 m/s but shall not exceed 4.0 m/s.  For solid alternative fuel belt velocities shall not exceed 1.0 m/s. Trough belt width shall not be less than 800 mm. For special applications 650 mm belts may be used. In packing plants 500 mm flat belts may be used. A minimum of 3 plies for synthetic fabric rubber belts shall be provided. Conveyor belt quality shall be standardized as far as reasonable for each belt width. For alternative fuel applications oil resistant, fire retardant and antistatic type belts shall be used.

Design Guideline (2/6) • The minimum distance between the center of the tail end

pulley and the skirt arrangement shall be larger than 2*belt width. As a minimum, the skirt should not start until full troughing of belt has been achieved

• Maximum conveyor slope: Maximum Slope

Eaw Material, wet slag

Clinker

Cement

Coal, Petcoke

All sections other than loading point

16 º

10 º

6º

15 º

At loading point

6º

0º

0º

5º

Design Guidelines (3/6) Idlers: •Carrier and return idler diameter shall be designed according to DIN (15207-1/22107) or CEMA (Class C, D or E). •Carrier and return idler diameter:  89 mm for 650 mm belts  ≥ 100 mm for > 650 to 1000 mm belts  ≥ 127 mm for belts greater than 1000 mm •Carrier idler spacing shall not exceed 1250 mm for all belt widths. •Carrier and return idler spacing for overland conveyors must be selected in order to limit the belt sag to maximum 1 % (100 % is defined as the distance between the idler centre lines). •High-density polyethylene impact bars or rubber protected impact idlers with spacing of maximum 300 mm shall be used at loading points. However impact bars are the preferred application. •Return idler spacing shall not exceed 3000 mm for all belt widths. Self-aligning belt idlers and guide idlers shall be used where necessary. •For conveyors handling sticky materials, return idlers shall be rubber disc rolls or anti-adhesive rubber tubes. •Permanent lubrication for all idler bearings sealed for life, shall be provided.

Design Guidelines (4/6) • Pulleys:  All drive pulleys shall have rubber lagging  Tail and take up pulleys: rubber lined or spiral wrapped wing pulleys. Wing type pulleys without spiral are not acceptable

• Belt tensioning stations:  For belt conveyors less than or equal to 50 m horizontal center distance, screw tensioning shall be used  For belt conveyors over 50 m horizontal center distance, vertical gravity or horizontal gravity shall be used

Design Guidelines (5/6) • Skirt plates and dust hood:  Skirt plates and dust hood shall extend not less than 2 m but maximum 5 m from loading point.  Skirt plates shall be made of wear resistant material.  Skirt plates shall be equipped with adjustable sealing rubber stripes or pads and shall be of the quick release type for easy adjustment

Design Guidelines (6/6) •

Covers:  Conveyors or parts thereof installed outside of buildings shall be covered if local weather condition do required it.  Belt covers shall be semi-circular metal sheets with handles on the accessible side of the conveyor and hinges on the opposite side.  For conveyors handling dry fine material (e.g. cement) the lower edges of the covers shall extend to 300 mm below the return belt line.

•

Uncovered Belt Conveyors  Long, horizontal belt conveyors running in the open (typically alongside preblending stockpiles) shall be equipped with a special device enabling the discharge of accumulated rain water during stoppage.

Example Calculation Belt Conveyor Transport Rate Calculation

Calculation (Target)

   

   

Company Plant HAC Code       Belt width Useful belt width Trough width Troughing angle Surcharge angle Belt inclination Belt speed Bulk density Volume flow rate th. Mass flow rate theo. Factor uneven loading Volume flow rate Mass flow rate Material bed height

: PT Holcim Indonesia Tbk : Narogong NR-3 FM : 51A-BC2 (Capacity 600 tph)         Standard troughing belt design design calc B [mm] 1000 b [mm] 850 s [mm] b [deg] 30 a [deg] 25 [deg] 12 v [m/s] 1,25 r [t/m3] 1,2 [m3/h] 492 [t/h] 590 0,9 443 [t/h] 531 [mm] 216

Material bed weight  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

kg/m

131

Installation Date Visa:  

: Clinker Transport : :    

at full belt load = full belt load

                                       

at full belt load and per m belt

   

1. Belt Capacity Calc. 2. Power Req. Calc.

Making BOQ for BC Installation (Purchased Material, Fabrication Cost, Installation cost, etc)

Making Technical datasheet as standard data for tendering process.

Holcim Standard Design Criteria

Bucket Elevator Design Basic

Bucket Elevator – Terminolgy and applications (1/2) Bucket elevators have established themselves as the most important type of vertical conveying systems in our industry since they are the simplest and most dependable units for lifting vertically most of the materials found in a cement plant. They are builtin with high-strength traction elements and operated with the minimum power consumption while coping with significant lifting heights. They are available in a wide range of capacities. The type of traction element should be chosen depending on the specific operating conditions of each particular application. The present paper is focused on bucket elevator technology and provision of design basics with a view of supporting Holcim plants in making the right selection for a given application.

Bucket Elevator – Terminolgy and applications (2/2) Belt bucket elevator

Chain bucket elevator

Traction element - Steel cable belt

Traction element - Chain



Tensile medium located over the width of the bucket



Tensile medium concentrated in 1 or 2 strands



Large surface area for attaching the bucket



Small area for attaching the bucket



Small surface pressures in the region of the



Large surface pressures in the region of the

attachment 

attachment

Tensile medium protected by rubber (elastomer)



against the effects of the material being carried,

Tensile medium directly in the area affected by the material being carried, direct abrasive attack

especially against abrasion 

No diminution of the breaking strength of the tensile



medium due to wear

Constant diminution of breaking strength of the tensile medium due to wear.



Vertical lifting heights up to 140m were reported





Thermal loading of the rubber limited to 120°C for



Elevators limited to around 60m in height due to chain weight

reasonable service life 

High thermal resistance (>120°C). Suitable for hot clinker handling

Conveyance speeds up to approximately 1.9m/s



Conveyance speeds up to approximately 1.9m/s for central chain



Conveyance speeds up to approximately 1.3m/s for round-link chain



3

Conveying capacity up to about 1750m /h



3

Conveying capacity up to about 700m /h for single bucket elevator



3

Conveying capacity up to about 1300m /h for double bucket elevator



Grains size up to 20mm and 60mm with special



Grains size up to 80mm



Higher electrical energy consumption than belt bucket

bucket mounting/fastening 

Lower specific power consumption when compared to chain bucket elevators



Very quiet running

elevators due to chain weight 

Higher running noise due to the polygon effect and despite lower conveying speed



Typical applications: Homo-silo feeding, Pre-heather tower feeding, Cement silo feeding, Packing machine



Typical applications: Raw mill recirculation, Clinker silo feeding, Cement mill recirculation

recirculation

Table 1: Comparison between belt and chain bucket elevator

Design Guideline (1/3) Drive  Gear reducers shall be shaft mounted or directly coupled to the head shaft.  Drive trains of bucket elevators shall be designed for 100 % of bucket filling

degree (waterline).

 Drives shall be supported at elevator steel casing.  Drives shall have non-return stops.  Only

direct-coupled auxiliary drives are acceptable. Provisions shall be incorporated to prevent over-speed of the auxiliary drive by accidental torque transmission from the main drive.

Casing  Casing shall be self-supporting, braced every 8-12 meters and at the head-

platform.

 For abrasive materials, boot casing loading chute and discharge chute shall be

provided with wear liners.

 Casing with openings for inspection, maintenance and cleaning, approximately 1.5

m high, having hinged doors shall be provided. Access shall be provided on both sides of the elevator.

Design Guideline (2/3) Buckets 

Bucket width shall not be less than 400mm.



Buckets for handling abrasive and/or coarse material shall be provided with a hard faced edge for wear protection.



Buckets shall have air vent holes for aerated material.

Chain Type 

High wear resistant central chain design is preferred.



Welded or forged link chains as well as “round link anchor type chains” (calibrated link) are acceptable.



Joining U-type shackles are not acceptable.



Drive sprockets or traction wheels shall be designed with replaceable segments.

Belt Type and Pulley Design 

Belt shall be made of steel reinforced rubber, unless otherwise approved in writing by the Project Owner.



Belt shall be heat resistant if required.



Drive pulley face can be either solid or lagged (rubber, ceramic) but shall be crowned, i.e. convex.



Self-cleaning cage type boot pulley shall be provided.

Design Guideline (2/3) Conveying Velocity and filling degree Type of Material

Filling Degree

Maximum speed in m/s depending on carrier element Chain type

Belt type

Round link

Central

Raw meal

< 75 %

1.3

1.9

1.9

Cement

< 75 %

1.3

1.9

1.9

Clinker & coarse materials

< 85 %

1.0

1.6

-

Bucket elevator maximum conveying speed and filling degree

Example Calculation : Bucket Elevator Material Handling

: Clinker

Required capacity

: 450 TPH

Conveying Height

: 50 m

Volume of Bucket

: 40 l

Bucket Spacing

: 400 mm

Bucket Projection

: 300 mm

Bucket Feeling Degree

:

70%

Bucket empty

:

20 kg.pcs

Speed of bucket

:

1,5 m/s

Density of Material

:

Calculate

Click

Holcim Standard Design Criteria

Air Slide Design Basic

Air slide– Terminolgy and applications The air-slide conveyor system is an air-activated, gravity-type conveyor using low-pressure air to aerate or fluidize pulverized material to such a degree that it will flow on a slight incline by force of gravity. The fluidized (air-activated) material in an inclined air-slide has the same behavior as a liquid in an inclined pipe. There are various names on the market for this pneumatic conveying system: Air Gravity Conveyor (AGC), Aeroslide, Airslide, Fluidor etc., some of those names being registered trademarks .

Design Guideline (1/4)  Inspection openings at upper channel are required, at least one per section.  At material feed points, cloth shall be covered by metal screen, wire mesh or

similar.

 Upper compartment shall be of high-top design (i.e. height is larger than width)

to ensure proper material flow and evacuation of conveying air.

 Flanged dust air take-off shall exclusively be at discharge end of the air slide

conveyor. Air slides longer than 50 m shall be equipped with a top casing of stepped heights. The intermediate venting of the conveyor by means of a dedusting unit shall be avoided wherever possible.

 Clean-out ports on the air chamber shall be located ahead of the discharge point

and ahead of any distribution/turn pots and diversion gates.

 Air pipes with throttle valve on each inlet shall be provided (air inlet lateral or

from bottom with deflector plates).

 Air permeability of the fabric shall be approximately 150 m3/m2h at 30 mbar.  Material speed - in general, the material speed in the air-slide should be between

2.0 to 3.0 m/s

Design Guideline (2/4) Fan-Type Blowers  Guide values for air pressure (including reserve) are:  Conveyor width  500 mm

60 mbar

 Conveyor width > 500 mm

80 mbar

 Air slides operating at lower pressure levels are subject to written

approval by the Project Owner.

 Guide values for specific air volume are:  Fine material (e.g. cement, raw meal)

: 2 m3/m2 per minute

 Coarse material (e.g. separator grits)

: 3.5 m3/m2 per minute

 Maximum speed: 3000 rpm for 50 Hz electrical supply, 3600 rpm for 60

Hz electrical supply.

Design Guideline (3/4)  Minimal recommended slopes for air-slides (based on polyester fabric): Type of Material

Minimum Slope

Cement

6°

Cement separator grits, Fly ash

12°

Raw meal

5°

Raw meal separator grits

15°

Filter dust

8°

 Design approach of an air-slide conveying system

Design Guideline (4/4)  Dimension of air slide.

Example Calculation : Cement Silo Feeding System Material: cement with 40% slag Required capacity: 400 TPH Conveying distance: 22 m  Determination of Air-slide size & slope: a.

Density cement with 40% slag: 950 Kg/m3 ==> Material flow = 421 m3/h (for 400 TPH)

b.

Air-slide wide :

c.

Upper compartment: high-top design : ==> h = 550 mm

d.

Maximal slope for cement:

Approx 500 mm ≥ 6°

   Air consumption/ pressure: a.

Specific air consumption:

b.

Aerated fabric section :

2 m3/m2 per minute (from supplier) A = 550 mm x 22 m =12.1 m2

 Air consumption: 12.1 m2 x 2 m3/m2 min

= 24.2 m3/min

a.

Air pressure:

p = 60 mbar



Technical Data Sheet

Conveyor width 500 mm ==>

Appendix – Spesific Weigth and Propertise Materials Material

Specific weights

Angle of Friction surcharge angle A B C For size of For civil (For (discharge silos & design conveyor angle) For conveyor size For conveyor H.P. For material loads stockpiles size design) design and size of silos & on building stockpiles structures 3

3

Angle of repose

3

[kg/m ]

[lbs/ft3]

[kg/m ]

[lbs/ft3]

[kg/m ]

[lbs/ft3]

[°]

[°]

[°]

[°]

Cement (40% Puzzolan)

950

59

1300

81

1600

100

10

-

0-5

-

Cement (40% Slag)

950

59

1300

81

1600

100

10

-

0-5

-

Cement (Portland)

1000

62

1400

87

1600

100

10

20

0-5

20

Clay: Fine (dry)

1000

62

1200

75

1600

100

25

30

5 - 10

-

Clay: Loose (dry)

1600

100

1800

112

2000

125

40

-

25 - 30

-

Clay: Loose (wet)

1800

112

2000

125

2000

125

50

15

25 - 30

-

Clinker

1200

75

1400

87

1600

100

35

30

20 - 25

30

Coal: Anthracite (as received)

800

50

900

56

1000

62

40

30

25 - 30

30

Coal: Bituminous

700

44

800

50

900

56

40

35

25 - 30

35

Coal: Pulverized/Meal

600

37

700

44

800

50

15

15

0-5

15

Gypsum (raw)

1280

80

1440

90

1600

100

40

35

25 - 30

-

Iron ore

2000

125

2400

150

2800

175

40

-

25 - 30

-

Kiln dust

600

37

800

50

1000

62

10

10

0-5

-

Limestone (crushed)

1400

87

1500

94

1700

106

40

35

25 - 30

35

Petcock (as received)

600

37

700

44

800

50

40

20

25 - 30

-

Petcock (meal)

400

25

550

34

750

47

-

-

-

-

Puzzolan: course (wet)

1200

75

1360

85

1520

95

30

-

15 - 20

-

Puzzolan: ground (dry)

950

59

1200

75

1360

85

20

-

5 - 10

-

Pyrite (pellets)

2100

131

-

-

-

-

35

-

20 - 25

-

Raw meal

900

56

1200

75

1500

94

15

15

0-5

15

Raw meal: blend. silo

900

56

1200

75

1500

94

15

15

0-5

15

Raw meal: cont. blend

900

56

1200

75

1500

94

15

15

0-5

15

Sand: dry (as received)

1400

87

1600

100

1680

105

40

35

25 - 30

35

Shale (crushed)

1300

81

1500

94

1680

105

40

35

25 - 30

35

1100

69

1200

75

1300

81

30

-

15 - 20

-

900

56

1000

62

1200

75

20

-

5 - 10

-

750

47

-

-

-

-

15

-

0-5

-

Slag: blast furnace granular, (wet) Slag: blast furnace, ground, (dry) Slag (pulverized 5600 Bl)

Holcim Indonesia Transport and Dedusting Workshop

Bucket

Air Slide

Holcim Standard Design Criteria

Pneumatic Conveying Design Basic

Pneumatic Conveying – Terminolgy and applications (1/2) A pneumatic conveyor system transports dry, free-flowing, granular material in suspension within a pipe or duct by means of an air-stream or by the energy of expanding compressed air. There are three basic categories that pneumatic transport systems fall under, depending on how the air is used to convey the material. 1.Pressure Systems - positive force of the air "push" the material from one place to another. Typically

used in the cement industry where there is one single pick up point and material is conveyed to multiple end points, (example FK pump system).

2.Vacuum Systems - uses negative pressure to "pull" material from one point to the next. These

"suction" conveying systems are typically used in applications where there are one or more pick-up points and material is conveyed to single destination, (example dust collection systems). 3.Air Gravity Systems - using low-pressure air to aerate or fluidize material to such a degree that it

will flow on a slight incline by force of gravity. This system is commonly known as an Air-slide system. Applications There are numerous applications in the cement industry that uses pneumatic transport systems such as e.g.: • Kiln feed transport • Vacuum clean-up systems • AFR handling (wood chips, dried-sewage sludge, etc.)

• Air-slide systems

• Pulverized coal, raw meal and cement transport

• Laboratory sampling systems

• Loading and unloading functions in shipping stations

• Dust collecting systems

Pneumatic Conveying – Terminolgy and applications (2/2)

Design Guideline (1/6) Pneumatic Transport Pneumatic transport for AFR is not recommended (in special cases yet possible), but for firing of fine solids at main burner, pneumatic injection is needed. This pneumatic transport should be as straight and as short as possible. 

Straight



< 30 m

Transport air Blower with variable speed allows adjusting air supply to different AFR and different feed rate. Guidelines for pneumatic injection in to main firing are: 

Speed 30 - 45 m/s



Fuel load 1 - 5 kg

fuel

/ kg

air

Cooled transport air may show less clogging problem for certain AFR: 

Animal meal < 20°C

Pipes must be as short and as straight as possible. Optimal is no bend and < 30 m horizontal

pneumatic transport.

Design Guideline (2/6) Solid air Ratio

Design Guideline (3/6) Rotary valve Blow through rotary valve A blow through valve shows less clogging for sticky material than a drop through valve with venturi injector. The venturi injection solution needs more air. Drop through valve with venturi is recommended only for very abrasive AFR (e.g. dried sewage sludge) because of the wear. Valve size definition:  Pipe diameter: DN 80, 100, 125 and 150 mm

Holcim recommendation: speed 30 - 45 m/s, fuel load 1 - 5 kg

fuel

/ kg

air

 Chamber size of valve: Density of AFR

Filling of the valve < 70% of theoretic maximal valve volume flow. Chamber cross section should be approx. same like transport pipe to prevent turbulences, pressure increase, wear rate

 Circumference speed < 0.4 m/s  Inlet size > 0.1 m2

 Number of compartments on valve wheel: Minimum 10 compartments to reach good sealing. Depending on pipe diameter and valve diameter 12 or 14 compartments are made.

Design Guideline (4/6) Rotary valve Blow through rotary valve

Design Guideline (5/6) Rotary valve Drop through rotary valve The drop through valve is recommended for fine very abrasive AFR. After the valve a venturi injection blows the AFR in the pneumatic line.   Valve size definition: Chamber size of valve: Density of AFR Filling of the valve < 33% of theoretic maximal valve volume flow. Chambers are rounded so that no AFR sticks in edges Circumference speed < 0.4 m/s Inlet size > 0.1 m2

Design Guideline (6/6)

Injector Smooth cross section transition



Venturi



Guide plate for injection 700

300

Ø 150

Ø 150

300

Pfister design venturi injector 5 - 10 t/h

200



Example Calculation : Pneumatic Conveying for FA Ambient Data : Altitude

: 100 m

Ambient Temp.

:

35 deg C

Conveying Air Temp.

:

80 deg C

Material

: Fly Ash

Required capacity

: 30 TPH

Conveying Height

: 25 m

Total pipe length

: 70 m

No. Of elbow

:

5 Pcs (r/D = 10)

No. Of pipe Sect.

:

1 Pcs

Pressure at line end

:

5 mbar

Calculate

Holcim Standard Design Criteria

Screw Conveyor Design Basic

Content • Screw conveyor   

Terminology Design characteristics Design criteria

Screw Conveyor - Terminology 

 Screw conveyor application

Terminology of screw conveyor (1) (4) (3) (7)

(6)

Fig. 1: Example horizontal screw conveyor

(5)

(2) (8)

(1) Inlet (2) Outlet (3) Bearing (4) Intermediate bearing (5) Screw shaft (6)Trough (7) Coupling (8) Gear motor

Fig. 2: Example screw conveyor with single inlet, multiple outlets

Screw Conveyor - Terminology  Screw conveyor application

Fig. 1: Example screw conveyor with multiple inlets, single outlet

Fig. 2: Example inclined screw conveyor

Fig. 4: Example vertical screw conveyor

Fig. 3: Example screw conveyor with two inlets, one outlet

Screw Conveyor - Design Characteristics (1/2) 

Overview trough design

Fig. 1: Example Standard trough design



Fig. 2: Example Standard pipe design

Fig. 3: Example Collecting trough design

Fig. 4: Example Double screw conveyor

Filling degree

Fig. 5: Example Screw conveyor 15% filling degree

Fig. 6: Example Screw conveyor 30% filling degree

Fig. 7: Example Screw conveyor 45% filling degree

Screw Conveyor - Design Characteristics (2/2) 

Overview flight design

Fig. 1: Continuous flights used in standard application

Fig. 2: Paddle plates used for mixing

Fig. 3: Ribbon flights, used for transport of viscous material

 Screw conveyor main design criteria A) Drive 

Gear reducer coupled directly to shaft end or shaft mounted drive is preferred design. Directly coupled V-belt drives and chain drives shall not be used



Installed drive power must be designed for 100% filling degree.

Screw Conveyor, Design Criteria B) Screw 

The screw conveyor flight diameter shall not be less than 230 mm.



Intermediate hanger bearings inside the trough shall be mounted on the trough, and separated from the cover.



Screw conveyors for dust from process gas filters (i.e., mills, kiln, clinker cooler) shall not be equipped with intermediate hanger bearings.



Covers shall be flanged-type, sealed, with quick-release type fasteners.



No less than one (1) inspection door (with protection mesh mounted under the inspection door to prevent physical contact with moving machinery) shall be provided



The filling degree shall be less than 33 % when intermediate hanger bearings are used.



For screw conveyors without intermediate hanger bearings, the filling degree shall be less than 75 %



Maximum circumferential speed: (not applicable for vertical screws)  1.50 m/s for easy flowing material (e.g., cement, raw meal)  0.75 m/s for other material (e.g., clinker, filter dust, etc.)

© Holcim Group Support Ltd 2011