Ball Mill Audits.ppt

Ball Mill Operation & Ball Mills Audits

Name : Shailesh Katare UE No : 1000814 Date : 13.10.2017 Time : 02.30 pm to 05.30 pm Venue : Kiln CCR Conference hall

Content • “A” level cement mill audit  

What is an “A” Level Audit? Targets of the “A” level audit

• “B” level cement mill audit  

  

What is a “B” Level Audit? Targets of a “B” Level Audit Requirements for the “B” level audit “B” level audit realization “B” level audit for VRM (vertical roller mill)

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What is a « A » level Audit?

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Long and short term data analysis • Production

• Evaluation and Potential estimation based on:

• Operation



• Quality



KPI

Comparison with other grinding systems Theoretical calculations

12 months 1 month 1 day

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What is a “B” Level Audit? KPI

Standard measurements

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Systematic Approach

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Standard Measurements – Tasks & Frequency one year 1. Circuit mat. granulometry

2. Mill longitudinal sieving 3. Ball charge filling degree 4. Mill material level 5. Mill ventilation 6. Separator Tromp curve

B-level audit

7. Separator ventilation 8. Mill internal conditions

9. Weigh feeder calibration 10. Instrument verification 11. Control loop verification

yearly stop

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Targets of a “B” Level Audit

kWh/t

t/h

- 5 - 15 %

%R45 um T [°C]

R 28

cm2/g

R2

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Logical realisation order 1. Define the cement type(s) for the audit 2. Gather the main machines design data

3. Central Control Room visit 4. Circuit visual inspection 5. Field activities: 

  

= standard measurements done simultaneously

Counters reading Sampling Measuring Mill, separator and auxiliaries internal visual inspection

6. Data compilation and analysis

7. Conclusions and report 9 CMS – MPT – Grinding Technology

Main machines design data t, t/h, kW, kJ/h, ºC, m3/h, mbar, m/s, m, m2, min-1,

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Mill Control System, Strategy and Trends • Information on: 



  



Available information at the CCR First contact with circuit layout Control system Control strategy First impression on operation Circuit stability

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Circuit / Visual inspection during operation

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Material and liquids sampling and measurements

A

temperature

Grinding aid

SF

CF

MF F

R

K

G

L

S

Water injection

C

SSR

MO 13 CMS – MPT – Grinding Technology

Material sample analysis A

Clinker

10 [kg]

1x per test 50, 25, 16, 8, 4, 2, 1, [mm], temperature

B

Gypsum

10 [kg]

1x per test 50, 25, 16, 8, 4, 2, 1, [mm] + %H2O

C

Limestone

10 [kg]

1x per test 50, 25, 16, 8, 4, 2, 1, [mm] + %H2O

S

Slag

10 [kg]

1 x per test 50, 25, 16, 8, 4, 2, 1, [mm] + %H2O

MO

Mill outlet

0.5 [kg]

200 [µm] Alpine Sieb pre-screening 1 x per 1/2 - ~1- 200 [µm] Laser 1.0 h (6x) Blaine [cm2/g] temperature (at least MO & R)

SSR Static. Sep. return A

Separator feed

CF

Sep. cyclones fines

SF

Sep. filter dust

F

Separator fines

R

Separator returns

MF

Mill filter dust

C

Cement 14 CMS – MPT – Grinding Technology

Power measurement Separator filter fan

Separator fan

Separator rotor

Mill fan Elevator

2 main groups:

Mill motor Auxiliaries

Fuel

Mill motor

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Mill air measurements Static pressure, temperature Airflow, static pressure & temperature

MFC MFO

MFI MO HGSA HGFA MI HGPA

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Mill material sampling = longitudinal sieving 1.1

1.2

20 cm 0.5 1m

1m

Mill cross section 1m

0.5

0.5 1m

1m

1m

1m

0.5

1.1

2.1

2.2

2.3

2.4

2.5

20 cm 17 CMS – MPT – Grinding Technology

Mill material samples analysis % residue accumulated

Sieve [mm]

Sample 1. Chamber

16

8

Blaine 4

2

1

0.5

0.2

0.12

0.09 0.063 0.045 cm2/g

1.1 1.2 1.3 1.4

2. Chamber

2.1 2.2 2.3 2.4 2.5 2.6 2.7 18 CMS – MPT – Grinding Technology

Mill internals: inspection and measurement Ball filling degree

Slot width, gaps, plugging, thickness

Ball filling degree

Slot width, flow setting

Slot width, gaps, plugging, thickness

State & thickness

State, position Liner residual lifting height

Liner type, state & rotation sense

Extreme ball size, state

Extreme ball size, classification, state

Material level & coating

Liner type, state & main dimensions

Material level & coating 19 CMS – MPT – Grinding Technology

Ball charge filling degree 1. Measure average internal diameter  Di 2. Measure height  h, in three different points along axis 3. Calculate h/Di and determine filling degree from diagram h Di

h/Di

D i

0,75

Di =

0,70

Mill diameter inside mill liners

0,65

0,60

filling degr

20

25

30

35

f [%]

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4. Material level 4.1 - 1st Compartment

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4. Material level 4.2 - 2

nd

Compartment

>> 50 [mm] bad ~ 50 [mm] good < 50 [mm] bad

<< 50 [mm] very bad

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Mill internal visual inspection

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8. Mill visual inspection

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Mill / Balls sampling

At least 4 samples Sampled balls -Sample weight kg Eq. Diameter mm Broken balls -Deformed balls -Broken balls % Deformed balls %

50 22.3 48 2 3 4 6

100 21.5 37 3 6 3 6

150 12.9 28 8 12 5 8

200 9.5 23 15 22 8 11

200 4.3 17 10 3 5 2 25

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Ball charge managementWear rate calculation on principle

Scraps S = 1t

Wear compensation WC = 24 t

Small balls SB = 3 t

Good balls GB = 79 t

Initial charge IC = 80 t 26 CMS – MPT – Grinding Technology

Net and gross wear rate

IC + WC – GB x 1’000’000

Gross wear =

[ gball / tcement ]

CP

IC + WC – (GB + SB + S) Net wear =

x 1’000’000

[gball / tcement ]

CP

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Separator / Visual inspection / 1st Generation

3

4

1

2

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Separator / Visual inspection / 2nd Generation

1

2

4

3

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Separator / Visual inspection / 3rd Generation

1

2 6 3 5

4

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Fans / Visual inspection

2

1

3

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Performance test data sheet Ball Mill Performance (Cement) Plant: Mill Nr.: Production

Date: Visa:

Cement mill 3 Mill production Cement type Fineness Feed moisture

Cement Composition

Material type Clinker Gypsum Limesone .... Total

Energy Consumption

Mill motors Separator rotor Separator fan Sepol Separator fan Stat. Press motor 1 Press motor 2 Mill fan Bucket elevators Auxiliaries Total mill system

Separator

Circulating factor Separator load - product / air ratio - feed / air ratio By-Pass Cut point Air flow rate Separator fan flap

202.3 [t/h] Type I-II 3660 [cm²/g] Blaine 1.8 [%] R 45 [µm] 0.240 [%] wet base

24.01.2003

Mill dimensions Diameter Length Motor

5.0 [m] 15.8 [m] 6000 [kW]inst.

Composit.[%] Product Moisture [%] H2O (wet base) 94.7 [%] [%] 4.3 [%] 5 [%] 1 [%] 2.5 [%] [%] [%] 100 [%] Feed moisture average 0.240 [%] 5'358 222 575 584 802 810 98 229 671 9'349

[kW]abs. [kW] [kW] [kW] [kW] [kW] [kW] [kW] [kW] [kW]

2.5 [ - ] calc 0.57 1.44 7 17.5 352000 100

[kg/m³] [kg/m³] [%] [µm] [m³/h] [%]

26.5 [kWh/t]

counter

[kWh/t] [kWh/t] [kWh/t] [kWh/t] [kWh/t] [kWh/t] [kWh/t] [kWh/t] 46.2 [kWh/t] 1.1 2.8 2.9 4.0 4.0 0.5 1.1 3.3

System Rotor

diameter height area speed Radial air speed Circumf. speed rotor

3.50 2.33 25.6 133.2 3.8 24.4

[m] [m] [m²] [min-1] [m/s] [m/s]

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Conclusion • Standard measurements give valuable information  

on grinding system performance on grinding system weak points

• B-level audit is the base-line of all medium-long term actions in process optimization • Detailed and accurate interpretation of the results are the key success factors of a B-level audit • Regular B-Level audits show a historic trend of the development of a grinding system and avoid a slow, but steady slow drift in the wrong direction

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