Annual Audit of CM 1

8/17/2019 Annual Audit of CM 1

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Process & Production Department

Annual Audit of Cement Mill 1

September 2015

BMIC


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Contents:

1- Filling Degree

2- Ball weight Method

3- Power Drawn

4-

Axial test ( granulometry curve )5- Separator Efficiency

6- Wear rate calculation

7- Ball charge sampling ( classification curve )

8- Quality Audit

9-

Mill Visit results10- Mill photos

11- Conclusion of audit


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1- Filling Degree

Cement Mill 1 Chamber 1 Chamber 2Charge % 90 90

Effective Comp. Diameter m 4.44 4.47

Effective Comp. Length m 4.5 9.75

Free Height , H m 3.07 3.006

Center Distance h = H-D/2 m 0.850 0.771

H/D % 0.691 0.672Filling Degree Q % 26.9 29.0

Bulk Weight [ W ] t/m3 4.3 4.5

Volume Of Compartment [ V ] m3 68.86 152.93

Charge F=q/100 × W × V t 79.7 199.6

Original Charge t 86.75 204.85

Charge Difference

t 7.1 5.25


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2- Ball weight Method

Ball weight method

Chamber 1 Chamber 2

Useful length 4.45 m 9.75 m

Type of lining Step shell , lifting Corregator , classifying

Type of diaphragm Intermediate Outlet

Diaphragm slots width ( Design ) Not Determined mm Not Determined mm

Diaphragm slots width ( Actual ) Not Determined mm Not Determined mm

Ball charge in metric tons ( Original) 86.75 t 204.92 t

Current Calculated Charge by ball sampling Method

Current Original Current OriginalDiameter 90mm 21.17 23.00

Diameter 80mm 27.55 28.90


Diameter 60mm 11.65 13.60 20.05 20.35

Diameter 50mm 0 10.05 10.25





Diameter 17mm 57.82 62.05Total 80.39 86.75 195.01 204.90

Filling degree 26.9 % 29 %

required tonnage -6.36 ton -9.91 ton

Total charge required , ton -16.27


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3- Mill Power Calculation

NET KW = 0.2846 DAWN

Chamber 1

D 4.44 Internal Diameter of Mill

A 0.804 1.073 - J

W 79.66 Charge weight in Tonnes

N 15 Mill speed in RPM

Net KW 1213.9 0.23

Gross KW 5200

Chamber 2

D 4.47 Internal Diameter of Mill

A 0.783 1.073 - J

W 199.57 Charge weight in Tonnes N 15 Mill speed in RPM

Net KW 2981.92 0.58

Gross KW 5200


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Total mill

Total Net absorbed Power, kw 4195.81

Net KW / Gross Kw ( mill) 0.81

Estimated power loss 0.073higher KW/t by 7.3 %

power loss % 7.3

Conclusion :

7.3 % power loss means that the consumption has increased by about 2 – 3 kw/t due to running mill with low

filling degree (Ch. 1) or low feed rate


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4- Axial test ( granulometry curve )

Note: Axial test has been done for 2 chambers using complete sieve shaker ( 7 sieves )

NoBlaine

cm2/gm850µ 212µ 150µ 90µ 75µ 45µ 36µ

chamber(1)

1 22.2 39.8 46.4 50.2 60.8

2 17.0 40.2 46.8 50.8 59.4

3 11.8 32.2 39.0 44.6 54.4

4 5.4 33.8 41.6 50.8 60.4

Diaphragm5.0 33.2 41.2 44.4 53.6

chamber(2)

5 2.0 21.0 30.0 38.4 47.8 46.4 58.6 1417.0

6 1.6 18.8 28.6 38.2 48.2 48.2 56.4 1361.0

7 1.8 17.2 25.6 33.4 43.2 63.8 68.4 1470.0

8 1.0 13.4 20.4 26.8 35.6 62.0 67.8 1757.0

9 0.8 9.2 15.8 21.8 32.0 54.6 59.8 1925.0

10 0.4 11.2 17.8 24.4 34.8 52.8 60.8 2004.0

11 0.6 7.0 13.2 19.4 28.0 53.8 62.0 1925.012 0.4 6.4 13.2 20.6 31.2 53.6 60.8 2004.0

13 0.2 5.8 10.2 14.2 23.8 50.6 59.0 2485.0

14 0.2 5.2 9.2 14.4 22.4 39.2 47.8 2422.0

Diaphragm 0.2 1.4 5.8 10.2 17.6 46.6 54.2 2223.0


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Axial test and Blaine Curve

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

1 2 3 4 Diaphram 5 6 7 8 9 10 11 12 13 14 Diaphram

850µ

212µ

150µ

90µ

75µ

I n t e r m e d i a t eD i a p h r a

m

O u t l e t D i a p h r a m


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The results analysis from both curves :

It seems from the curve that the size reduction and Blaine are good through the mill chambers

but there are some points have to be taken in consideration as following:

0.0

500.0

1000.0

1500.0

2000.0

2500.0

3000.0

5 6 7 8 9 10 11 12 13 14

B l a i n e

c m 2 / g

Effective Length ( m )

2nd Chamber Chart (Blaine cm2/g)

blaine

cm2/gm


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1- Point 1 & 2 : A slight flat curve means that Ѳ 90 & 80 need to be charged

2- Point 3 : means that the combination of Ѳ 80 & 70 has a good performance

3-

Point 4 : prove that the quantity of Ѳ 60 is so less to play its role and from wear rate calculation

method shown the most high wearable balls is Ѳ 60 and from visual inspection shown that amount

of Ѳ 60 is less , so we have to add Ѳ 60 grinding balls to Ch 1

4- Very small Clinker nibs at intermediate diaphragm and by adding Ѳ 90 & 80 , it will disappear totally

5- Point 5 & 6 , Show a poor preparation of Ѳ 60 from 1st

chamber which make the curve little flat and

it will disappear by adding Ѳ 60 to chamber 1

6- Point 10 & 12 show a sharp raise where by visiting mill in both points there is unclassified balls

where Ѳ 60 & 50 was there which interrupt the curve

7- A size reduction at the last of chamber 2 shows the small balls Ѳ 30 & 25 & 20 & 17 have a good

performance

Conclusion:

1- Chamber 1 : add 2 ton Ѳ 90 and 2 ton Ѳ 80 and 2 ton Ѳ 60

2- Chamber 2 : not recommended to add grinding media as high filling degree 29 % also the level of

balls have reached to the outer diameter of the ventilation grid


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5- Separator Efficiency

Passing %Separator

feed a , Mill

outlet ( % )

Fine fraction

f ( % )

Coarse fraction

g , tail (%)

Circulation

factor

Separator

Efficiency

36µ 61 75 39.4 1.65 74.6

45µ 77 92.6 51.4 1.61 74.7

75µ 77.2 93 52 1.63 74.0

90µ 87.4 95.6 67.2 1.41 77.8

150µ 93.2 96.6 79.8 1.25 82.7

212µ 98.4 98.8 97.2 1.33 75.3

850µ 99.8 100 99.2 1.33 75.2

Sum 594 651.6 486.2 1.53 71.5

Blaine cm2/g 2004 3241 1303

Conclusion of the test:

The circulation load of the mill is about 1.53 which show a good performance of both mill

chambers with feed 140 – 145 t/h also the Separator Efficiency is about 71.5 % which

show a good separator role


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6- Wear rate calculation :

size

one ball

original

weight

(kg)

TonnageQuantity

of Balls

Quantity of

collected

samples

from mill

weight of

samples

collected

from mill

(kg)

average

wt. of

one ball

(Kg)

loss on

one ball

(gr)

% of

wear

per ball

Current

Ball Wt

in mill

total charge

weight required

( ton)

1st Chamber

90 ø 3.00 23.00 7667 43 118.759 2.76 0.24 7.9 21.17 1.83

80 ø 2.10 28.90 13762 44 88.09 2.00 0.10 4.7 27.55 1.35

70 ø 1.41 21.25 15071 50 66.38 1.33 0.08 5.8 20.01 1.24

60 ø 0.888 13.60 15315 15 11.414 0.761 0.13 14.3 11.65 1.95

Total ( 1st chamber )

Wear rate86.75 51815 284.6 80.39 6.36

2nd Chamber

60 ø 0.888 20.35 22917 29 25.38 0.875 0.01 1.5 20.05 0.30

50 ø 0.514 10.25 19942 19 9.58 0.504 0.01 1.9 10.05 0.20

40 ø 0.263 10.20 38783 41 10.41 0.254 0.01 3.5 9.84 0.36

30ø 0.111 20.40 183784 410 44.79 0.109 0.00 1.6 20.08 0.32

25 ø 0.064 30.60 476636 765 45.68 0.060 0.00 7.0 28.46 2.14

20 ø 0.033 51.05 1556402 2240 70.10 0.031 0.002 4.6 48.71 2.34

17 ø 0.020 62.05 3071782 2811 52.91 0.019 0.0014 6.8 57.82 4.23

Total ( 2st chamber )

Wear204.9 5370245 258.8 195.01 9.89

Total mill291.7 5422060 275.4 16.2


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Wear rate summary:

Current Ball charge 275.4 ton

Original charge 291.6 ton

Ball Added to mill till now 14.7 ton

Total mill production , 2014 -2015 1,414,927 tontons added to 1st

chamber7.5

wearable tons during operation 30.85 tonTons added to 2nd

chamber7.2

Mill wear rate g/t21.8 gr/t

1st chamber wear rate9.76 gr/t

2nd chamber wear rate12.08 gr/t


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7- Ball charge sampling ( classification curve )

Ball charge sampling ( mass % )ɸ / meter 1 m 2.5 m 4 m 4.5 m 6 m 7.5 m 9 m

ɸ 60 31.9 7.4 0.0 1.7 6.5 4.8 0.0

ɸ 50 8.9 4.1 0.0 2.9 2.8 1.1 0.0

ɸ 40 2.8 10.6 0.0 2.0 1.4 4.4 0.0

ɸ 30 0.0 18.0 8.2 16.4 9.2 40.6 13.2

ɸ 25 15.6 23.1 21.9 30.3 16.3 12.1 13.4

ɸ 20 15.8 22.7 69.9 30.6 30.6 21.9 29.2

ɸ 17 24.9 14.1 0.0 16.1 33.1 15.1 44.3

Curve of balls gradation in 2nd

chamber ( Ѳ 60,50,40 )

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

1 m 2.5 m 4 m 4.5 m 6 m 7.5 m 9 m

ɸ 60

ɸ 50

ɸ 40


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Curve of balls gradation in 2nd

chamber ( Ѳ 30, 25, 20, 17 )

Summary of curve:

Classification of the balls in 2nd

chamber is unclassified well where some bigger balls at end ofchamber and smaller at beginning of the chamber

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

1 m 2.5 m 4 m 4.5 m 6 m 7.5 m 9 m

ɸ 30

ɸ 25

ɸ 20

ɸ 17


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8- Quality Audit

Quality

Feed components Clinker Gypsum Additives

percent % 88.5 6.5 5

cement Temperature 115 - 125 C

Clinker mineralogy % C3S 50 - 52 %C4AF 11.83

% C2S 21 – 24.0 %C3A 7.85

Note : C2S is little higher which need more grinding efficiency and draw more

power consumption

Blaine 3136 cm2/gr

Residue 90µ 0.6 %

Residue 45µ 13 - 14.5 %


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9-Mill Visit results : 1st Chamber

Measured volume load 26.7 %Lining condition there is displacement in some rows and a “ Domino Effect “ appear in plates

Maximum ball diameter 90 mm

Minimum ball diameter 56 mm

Ball charge condition Regular with normal worn out

Material level under/over balls Moderate/little Over , 1/4 ball appear

Coating on lining Very slight

Coating on balls Slight

Uncrushed particles at the

diaphragmA bit

Diaphragm condition Semi- Blocked and Need to routine clean

Maximum width of slotsNot Determined

Wear rate of lining plates Not Determined

Slots blocked Semi- Blocked

Central screen condition No Screen found and new fabricated one has a large Slot width ( 9 – 13 mm )


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1st

Chamber Photos:


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9- Mill Visit results : 2nd

Chamber

Measured volume load 29 %Lining condition Regular , but a slight Coat there

Maximum ball diameter 58 mm

Minimum ball diameter 15 mm

Ball charge condition Regular with normal worn out

Material level under/over balls Over 4 -6 cm

Coating on lining Slight Coat

Coating on balls There is a coat layer on Balls due to High CM temp + Higher water flow

Uncrushed particles at the diaphragm A bit

Outlet Diaphragm condition Good and slight blocked

Maximum width of slots Not Determined

Wear rate of lining plates Not Determined

Ball Classification Un Classified Well

Central screen condition Good

Water Nozzle 5 cm gap between diaphragm and flange / allow for escaping small balls


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2nd

Chamber Photos:


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11 - Conclusion of Audit: Recommended actions

1-

Addition of 2 tons for each Ѳ 90 & Ѳ 80 & Ѳ 60 for 1

st

chamber2- Not recommended now to add grinding media to 2

nd chamber as high filling degree and level of

balls near to ventilation grid

3- Measuring Slots width for both diaphragms not determined ( Recommended )

4-

A good Separator Efficiency which is about 71 % and By- pass 19 %

5- A circulation factor is about 1.53 which is good

6-

Mill wear rate is about 22 gr/t

7-

High C2S phase means more energy for grinding

8-

High Power consumption by 2- 3 kwh/t

9- Physical Condition of grinding balls in 1st

chamber is good except Ѳ 60 mm where more

deformation there

10- Displacement of some rows in 1st

chamber is observed , fast action to adjust it is

recommended

11-

Measuring the lifting lining wear rate nor determined , ( recommended )

12- Observed wear rate for head liner of 1st

chamber

13-

A bit clinker nibs at intermediate diaphragm has observed

14- Condition of intermediate diaphragm is semi blocked and need routine cleaning


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15- Intensive follow up of metal trap to eliminate the scrap from mill which block the diaphragm

16- The new fabricated ventilation grid has a higher Slot width bigger than inter. diaphragm slot

width which allow for escaping the oversize particle to 2nd chamber17- Physical Condition of grinding balls in 2

nd chamber is good

18-

Observed coat formation layer on the 2nd

chamber grinding media & liners due to operation

mill with higher cement temperature or higher water flow or low ventilation, recommended

controlling temp. or using a grinding aid

19- The classification of the grinding media in 2nd

chamber is not good but can consider accepted

20-

The space 5 cm between water nozzle flange and outlet diaphragm will allow for escapingmore fine media to the 1

st chamber, recommended to close the gap.

21- The condition of diaphragm is accepted but need a routine cleaning for improving the

performance

22- Slot width of outlet diaphragm not determined , recommended to measure

23- Lining wear rate for 2nd

chamber not determined , recommended to measure

CM 1 Audit 2015

Documents

Annual Audit of CM 1