Mill

Excursion of Loesche Mills with
RAMCO Group
N. Ravishankar:
Sr. VP (Manufacturing)
RAMCO Group – An Overview

RAMCO Group was founded by Late Sri P.A.C.
Ramasamy Raja, a great visionary of the last
century.

Now it is headed by his Proficient Successor
Sri P.R.Ramasubrahmaneya Rajha.

The group’s business interests are in the areas
of cement, cement asbestos sheets, textile and
software.

Group’s Total turnover is $ 1000 Million

Group’s Employees : >14000
2
RAMCO Group of Companies at a Glance






Textiles
◦ Rajapalayam Mills Ltd
◦ Sudarshan Spinning Mills
◦ Sri Vishnu Shankar Mill Ltd
◦ Rajapalayam Spintext
◦ Sri Ramco Spinners
◦ Rajapalayam Textiles
◦ Sandhya Spinning Mills Ltd
◦ Thanjavur Spinning Mill Ltd.
Fiber Cement
◦ Ramco Industries Ltd
◦ Ramco Lanka (P) Ltd
Cement
◦ The Ramco Cements Ltd (RCL)
Software
◦ Ramco Systems Ltd
Surgical Cotton
◦ The Ramaraju Surgical Cotton Mills Ltd
Bio Technology
◦ Shri Ramco Biotech
The Ramco Cement Limited – An Overview
 The Ramco Cement Ltd. (TRCL), formerly known as
Madras Cements Limited, is a flagship company of RAMCO Group.
 TRCL is having 5 Integrated cement manufacturing units, 3 cement
grinding units with the total annual capacity of 13 Million TPA.
 TRCL is producing mainly OPC and PPC as per Bureau of Indian
Standards (BIS ) quality , meeting all regional market demand.
ISO 14001:2004
ISO 9001:2008
IS 18001:2007
4
The Ramco Cement Limited – An Overview

Special emphasis is always given to the highest quality standards
for the product.

The Company believes in continual upgradation of technology
and skill of people.

All its plants are of the latest state of the art technology prevailing
during the time of inception and continually upgraded.

The plants are highly energy efficient and eco-friendly.
5
Loesche Vertical Roller Mills at TRCL
Location
Material
No. of
Mills
Alathiyur 1&2
Limestone
2
LM 38.3
Alathiyur 1&2
Coal
2
LM 20.2 D
Clinker
1
LM 56.2+2 C
Jayanthipuram1
Slag
1
LM 46.2+2 CS
Jayanthipuram-2
Limestone
1
LM 46.4
Jayanthipuram-2
Coal
1
LM 28.2 D
Ariyalur-1
Limestone
1
LM 46.4
Ariyalur-1
Coal
1
LM28.2 D
Ariyalur-1
Clinker
1
LM56.3+3 C
Alathiyur 2
Mill Size
6
7
Alathiyur Plant
Line 1
Line 2
Commissioned
(year)
1997
2001
Kiln
FLS – *2300 t/d
FLS - *3000 t/d
Raw Mill
Loesche LM 38.3
Loesche LM 38.3
Coal Mill
Loesche LM 20.2D
Loesche LM 20.2D
Cement Mill
O.K 33.4
Loesche
LM 56.2+2 C
* Kiln Capacity later upgraded to 3500 tpd
8
Alathiyur Plant
Unit
Raw Mills
LM 38.3
Coal Mills
LM 20.2D
Cement Mill
LM 56.2+2C
Rated Output
t/h
215
21
*PPC - 220
Feed Moisture
%
5-10
15
3
%R90µ /
cm2/g
17
15
3400
Table Diameter
mm
3800
2000
5600
Mill Motor
Rating
kW
1750
400
4000
Fan Motor
Rating
kW
1750
750
2850
** LSKS 52
** LKS 40 ZD
LSKS 85 C
Description
Product
Fineness
Classifier Size
* PPC with 25% Ash ( Ratio of Dry and Wet 50:50)
** Later Upgraded to High Efficiency Classifier
9
Alathiyur Plant
 First Loesche mills in TRCL were commissioned at Alathiyur , Unit-1 in 1997.
- Raw Mill LM 38.3
- Coal Mill LM 20.2D
 Looking into successful performance of Loesche mills, same mills were repeated
for Alathiyur, Unit-2 .
 Additionally a cement mill LM 56.2+2 C was also ordered for PPC @3400 Blaine
at Alathiyur, Unit-2.
 Outstanding performance of all the Loesche mills at Alathiyur plant and efficient after
sales services opened a gateway for Loesche for future projects of TRCL.
 Subsequently TRCL decided to enhance the kiln capacity and maximum usage of
petoke for kiln/calciner firing. This necessitated extra output from raw mills and coal
mills at reduced product residue.
10
Alathiyur Plant
11
Alathiyur Coal Mills LM 20.2 D: Classifier Upgradation
Background
 Driven by Techno-economical reasons, TRCL started using petcoke
 Due to the typical burning characteristics, the petcoke has to be ground to a
fineness below 2% on 90 micron for complete combustion.
 The then old generation classifier was not able to provide efficient
separation leading to unstable mill operation.
 The kiln capacity was under compromise and therefore it was decided to
replace the classifier from old LKS to latest generation cage wheel type
LSKS classifier.
12
Alathiyur Coal Mills LM 20.2 D: Classifier Upgradation
LKS Vs. LSKS
LKS Classifier
New LSKS Classifier
13
Alathiyur Coal Mills LM 20.2 D: Classifier Upgradation
Comparative Operating Data in Petcoke & Coal Grinding
Description
PETCOKE
COAL
Before
After
Before
After
LKS 40 ZD
LSKS 36 ZD
LKS 40 ZD
LSKS 36 ZD
13
16-17
23
28
4
1.5 -2
18
< 16
Specific Power: Mill
(kWh/t)
19.2
15.5
12.17
8.21
Specific power: Fan
(kWh/t)
32.3
26.5
19.13
16.96
Total Specific Power
(kWh/t)
51.5
42.0
31.30
25.17
Classifier Size
Output (dry basis)
(t/h)
Product Residue @ 90
µm (%)
14
Alathiyur Coal Mills LM 20.2 D: Classifier Upgradation
Benefits Achieved
 After
classifier
retrofit,
the
mill
performance improved significantly and
TRCL could use 100% petcoke @1.52% R90μ.
 The homogeneous quality of pulverised
petcoke improved its burning efficiency
 Kiln could be operated to its full
potential.
 Abnormal
coatings
in
kiln
got
eliminated.
15
Alathiyur Plant
16
Alathiyur Raw Mills LM 38.3: Classifier Upgradation
Background
 Raw mills were designed for a feed moisture of 6% normal & 10% maximum.
 Over a period of time, the normal feed moisture increased to more than 10% causing
reduced output from raw mills to 205-210 t/h from normal 215-220 t/h.
 Since more heat was required for drying, the gas volume was to be increased in mills
and thereby causing higher product residue.
 Kiln feed had to be reduced as the raw mills were unable to support the raw meal
requirement.
 At high residue of raw meal on 212 µm, problems related to clinker burning resulted in
high free lime of >2.5%.
 Raw mills with Hot Air Generator (HAG) met the raw meal requirement but residue was
still high.
17
Alathiyur Raw Mills LM 38.3: Classifier Upgradation
Background

MCL decided to further enhance the kiln capacity to 3500 t/d

Accordingly the revised capacity requirement from each raw mill
230 t/h to support the upgraded kiln.

Product residue @212 µm was required to be less than 2%.

It was decided to replace the then classifier LSKS52 to higher size LSKS57
equipped with Vortex Rectifier

Due to higher air flow requirements, fans were upgraded and ducts were
enlarged.
was >=
18
Alathiyur Raw Mills LM 38.3: Classifier Upgradation
Classifier Details
Vortex
Rectifier
Rotor
LSKS
LSKS With Vortex Rectifier
19
Alathiyur Raw Mills LM 38.3: Classifier Upgradation
20
Alathiyur Raw Mills LM 38.3: Classifier Upgradation
Vortex Rectifier
Without Vortex Rectifier
With vortex Rectifier
Hard twisted gas flow created by high
speed rotation of classifier rotor
Uniform and Laminar Flow
21
Alathiyur Raw Mills LM 38.3: Classifier Upgradation
Vortex Rectifier
Flow Characteristics
Classifier with Vortex Rectifier
Results of CFD
Classifier without Vortex Rectifier
Laminar Flow
Turbulent Flow
22
Alathiyur Raw Mills LM 38.3: Classifier Upgradation
Comparative Operating Data
Description
Classifier Size
Feed Moisture (%)
Mill Output (t/h) dry
Product Residue
212 µm (%)
Product Residue
90 µm (%)
Total Specific Power
(kWh/t)
Mill + Fan
Before
Modification
After
Modification
LSKS 52
LSKS 57
>=10
>=10
207
232
2.5-3.0
1.5 - 2.0
19-20
16-17
12 -13
11
23
Alathiyur Raw Mills LM 38.3: Classifier Upgradation
Benefits Achieved
 Output increased to 232 t/h at feed moisture >=10% to cater kiln requirement
 The mill can be operated at 240t/h-245t/h with increased Hot Gas from HGG.
 Saving of about 1-2 kWh/t in specific power drawn by mill and fan.
 Product Residue on 212 µm (crucial for burning ) came down to 1.5-2%.
 With improved particle size distribution of mill product, free lime in clinker
reduced to <2% leading to improved clinker quality : C3S >=55%
 Kiln is being operated to its full capacity due to adequate quality and quantity
of raw meal.
 Stable Kiln Operation
24
Alathiyur Plant
Summary
 Both the raw mills with classifier equipped with vortex rectifier are in smooth
operation and given tremendous advantage.
 Both the coal mills upgraded with LSKS classifier are grinding successfully
100% petcoke at 1.5-2% residue on 90 micron.
 Performance of LM 56.2+2 C is considered as benchmark in the group.
 TRCL is satisfied with overall performance of all the Loesche mills at Alathiyur.
 Due to significant energy saving in grinding section, TRCL achieved 63-64
kWh/t in PPC for complete plant, which is benchmark in the industry.
 Upgrading LM 56.2+2 C with new LSVS classifier is under discussion.
25
Jayanthipuram Plant
26
Jayanthipuram Plant
Line 1
Line 2
Commissioned
(year)
2000
2008
Kiln
FLS – 3200 t/d
FLS - 4200 t/d
Raw Mill
ATOX 37.5
Loesche LM 46.4
Coal Mill
ATOX 20
Loesche LM 28.2 D
Cement Mill
Loesche LM 46.2+2 CS
FLS Ball Mill with
AMCL Pre-Grinder
27
Jayanthipuram Plant
Description
Unit
Raw Mill
LM 46.4
Coal Mill
LM 28.2D
Cement Mill
LM 46.2+2CS
Rated Output
t/h
400
40
Slag - 75
Feed Moisture
%
4
12
15
Product
Fineness
%R90µ /
cm2/g
15
15
4500
Table Diameter
mm
4600
2800
4600
Mill Main Motor
kW
2400
600
3200
Mill Fan Motor
kW
3200
750
1750
LSKS 76
LKS 43 ZD
*LJKS
Classifier Size
*
Later Upgraded to High Efficiency LSKS type Classifier for OPC/PPC
28
Jayanthipuram Plant
Summary
 In 2000, first Loesche mill LM 46.2+2 CS was commissioned for slag grinding.
Later TRCL started producing OPC and PPC from this mill.
 Looking into encouraging results of classifier upgradation at Alathiyur, the
cement mill LM 46.2+2 CS at Jayanthipuram was upgraded with LSKS
classifier.
 Later in 2008, one raw mill LM 46.4 and one coal mill LM28.2D were
commissioned in Jayanthipuram Unit-2.
 TRCL is satisfied with overall performance of all the Loesche mills at
Jayanthipuram.
 Upgrading LM 46.2+2 CS with new LSVS classifier is under discussion.
29
RAMCO CEMENT
ARIYALUR PLANT
30
Ariyalur Plant
Line 1
Commissioned
(year)
2008-2009
Kiln
FLS – 4300 t/d
Raw Mill
Loesche LM 46.4
Coal Mill
Loesche LM 28.2 D
Cement Mill
Loesche LM 56.3+3 C
31
Ariyalur Plant
Description
Unit
Raw Mill
LM 46.4
Coal Mills
LM 28.2 D
Cement Mill
LM 56.3+3 C
Rated Output
t/h
335
40
*PPC - 305
Feed Moisture
%
9
12
3
Product
Fineness
%R90µ /
cm2/g
2% R212µ
15
3400
Table Diameter
mm
4600
2800
5600
Mill Main Motor
kW
2400
600
5400
Mill Fan Motor
kW
3200
750
2850
LSKS 76
LSKS 43 ZD
**LSKS 92 C
Classifier Size
* PPC with 25% Ash (Ratio of Dry and Wet 50:50)
** Later Upgraded to High Efficiency Classifier
32
Ariyalur Cement Mill LM 56.3+3C: Classifier Upgradation
Background
 All the Loesche mills at Ariyalur were
commissioned in 2008-09
 PG test was successfully completed for
all the mills.
 Later TRCL started using petcoke for kiln
firing and clinker quality deteriorated.
 Performance
deteriorated
of
cement
mill
and
TRCL
decided
also
to
upgrade it by LSVS classifier .
33
Ariyalur Cement Mill LM 56.3+3C: Classifier Upgradation
Pre-Conditions
 At the time of retrofit, mill performance was jointly recorded as:
Mill Output
t/h
285-290
Product Blaine
cm2/g
3400
Total Sp Energy
kWh/t
26
Fly Ash
%
28
Dry Fly Ash & Wet Ash
Ratio
50:50
Total Sp Energy @meter
(Mill+Fan+Classifier)
kWh/t
25.5
Guarantees
Increase in Mill Output
%
10
Reduction in Specific Power
kWh/t
1-1.5
34
Ariyalur Cement Mill LM 56.3+3C: Classifier Upgradation
Comparative Operating Data
Description
Classifier Size
Mill Output (t/h) dry
Product Fineness cm2/g
Grinding Aid (g/t)
Total Specific Power
(kWh/t) @Meter
(Mill + Fan + Classifier)
Before
Modification
After
Modification
LSKS 92C
LSVS 97C
285
325
3400
3400
Nil
Nil
25.5
22.5 - 23.0
Improvement
40 ( 14% )
2.5 – 3.0
35
Ariyalur Cement Mill LM 56.3+3C: Classifier Upgradation
Benefits Achieved
 Output increased by 40 t/h i.e. about 14 %
 Saving of about 2.5 – 3.0 kWh/t in specific energy .
 Reduced vibration trippings and Stable mill operation
 Reduced fluctuations in mill motor power.
36
CONCLUSION
 Association of TRCL and Loesche has been quite long which is
constantly strengthen by prompt & efficient services of Loesche.
 Loesche Mills are the Bone - Marrow of TRCL Cement Plants.
 TRCL finds Loesche Mills are the simplest from operation and
maintenance aspects.
 TRCL is planning to upgrade Jayanthipuram Cement Mill LM
46.2+2CS and Alathiyur Cement Mill LM 56.2+2C by LSVS classifier.
37
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