04 Ravishankar Madras Cement Journey of Loesche Mills in Ramco Group

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Excursion of Loesche Mills with

RAMCO Group

N. Ravishankar: Sr. VP (Manufacturing)


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RAMCO Group An Overview

RAMCO Group was founded by Late Sri P.A.C.Ramasamy Raja, a great visionary of the lastcentury.

Now it is headed by his Proficient SuccessorSri P.R.Ramasubrahmaneya Rajha.

The groups business interests are in the areasof cement, cement asbestos sheets, textile andsoftware.

Groups Total turnover is $ 1000 Million

Groups Employees : >14000

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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

RAMCO Group of Companies at a Glance


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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 9001:2008ISO 14001:2004 IS 18001:2007

The Ramco Cement Limited An Overview

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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.

The Ramco Cement Limited An Overview


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Loesche Vertical Roller Mills at TRCL

Location Material No. of

Mills

Mill Size

Alathiyur 1&2 Limestone 2 LM 38.3

Alathiyur 1&2 Coal 2 LM 20.2 D

Alathiyur 2 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


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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 LoescheLM 56.2+2 C

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* Kiln Capacity later upgraded to 3500 tpd


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* PPC with 25% Ash ( Ratio of Dry and Wet 50:50)

Description UnitRaw MillsLM 38.3

Coal MillsLM 20.2D

Cement MillLM 56.2+2C

Rated Output t/h 215 21 *PPC - 220

Feed Moisture % 5-10 15 3

ProductFineness

%R90 /cm2/g

17 15 3400

Table Diameter mm 3800 2000 5600

Mill MotorRating

kW 1750 400 4000

Fan MotorRating kW 1750 750 2850

Classifier Size ** LSKS 52 ** LKS 40 ZD LSKS 85 C

** Later Upgraded to High Efficiency Classifier

Alathiyur Plant


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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.

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Alathiyur Plant


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Alathiyur Plant


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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.

Alathiyur Coal Mills LM 20.2 D: Classifier Upgradation

Background

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LKS Classifier New LSKS Classifier

LKS Vs. LSKS

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DescriptionPETCOKE COAL

Before After Before After

Classifier Size LKS 40 ZD LSKS 36 ZD LKS 40 ZD LSKS 36 ZD

Output (dry basis)

(t/h)

13 16-17 23 28

Product Residue @ 90m (%)

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

Comparative Operating Data in Petcoke & Coal Grinding

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Benefits Achieved

After classifier retrofit, the mill

performance improved significantly and

TRCL could use 100% petcoke @1.5-

2% R90.

The homogeneous quality of pulverised

petcoke improved its burning efficiency

Kiln could be operated to its full

potential.

Abnormal coatings in kiln got

eliminated.

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Alathiyur Plant


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Background

Alathiyur Raw Mills LM 38.3: Classifier Upgradation

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 m, 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.

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Background

MCL decided to further enhance the kiln capacity to 3500 t/d

Accordingly the revised capacity requirement from each raw mill was >=230 t/h to support the upgraded kiln.

Product residue @212 m was required to be less than 2%.

It was decided to replace the then classifier LSKS52 to higher size LSKS57equipped with Vortex Rectifier

Due to higher air flow requirements, fans were upgraded and ducts were

enlarged.

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Classifier Details

VortexRectifier

LSKS With Vortex RectifierLSKS

Rotor



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Vortex Rectif ier

With vortex Rectifier

Uniform and Laminar Flow

Without Vortex Rectifier

Hard twisted gas flow created by highspeed rotation of classifier rotor



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Classif ier without Vortex Recti fier

Classifier with Vortex Rectifier

Laminar Flow

Turbulent Flow

Results of CFD

Flow Characteristics

Vortex Rectifier

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DescriptionBefore

ModificationAfter

Modification

Classifier Size LSKS 52 LSKS 57

Feed Moisture (%) >=10 >=10

Mill Output (t/h) dry207 232

Product Residue

212 m (%)2.5-3.0 1.5 - 2.0

Product Residue

90 m (%)

19-20 16-17

Total Specific Power(kWh/t)

Mill + Fan

12 -13 11

Comparative Operating Data

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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 m (crucial for burning ) came down to 1.5-2%.

With improved particle size distribution of mill product, free lime in clinker

reduced to =55%

Kiln is being operated to its full capacity due to adequate quality and quantity

of raw meal.

Stable Kiln Operation

Benefits Achieved

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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 63-64kWh/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.

Summary

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Alathiyur Plant


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Jayanthipuram Plant


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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 CSFLS Ball Mill withAMCL Pre-Grinder

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Jayanthipuram Plant


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Description UnitRaw MillLM 46.4

Coal MillLM 28.2D

Cement MillLM 46.2+2CS

Rated Output t/h 400 40 Slag - 75

Feed Moisture % 4 12 15

ProductFineness

%R90 /cm2/g

15 15 4500


Mill Main Motor kW 2400 600 3200

Mill Fan Motor kW 3200 750 1750

Classifier Size LSKS 76 LKS 43 ZD *LJKS

* Later Upgraded to High Efficiency LSKS type Classifier for OPC/PPC28

Jayanthipuram Plant


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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 atJayanthipuram.

Upgrading LM 46.2+2 CS with new LSVS classifier is under discussion.

Summary

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Jayanthipuram Plant


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RAMCO CEMENTARIYALUR PLANT

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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

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Ariyalur Plant


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* PPC with 25% Ash (Ratio of Dry and Wet 50:50)

Description UnitRaw MillLM 46.4

Coal MillsLM 28.2 D

Cement MillLM 56.3+3 C

Rated Output t/h 335 40 *PPC - 305

Feed Moisture % 9 12 3

ProductFineness

%R90 /cm2/g

2% R212 15 3400


Mill Main Motor kW 2400 600 5400

Mill Fan Motor kW 3200 750 2850

Classifier Size LSKS 76 LSKS 43 ZD **LSKS 92 C

** Later Upgraded to High Efficiency Classifier

Ariyalur Plant


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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 of cement mill also

deteriorated and TRCL decided to

upgrade it by LSVS classifier .

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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 kWh/t 25.5

(Mill+Fan+Classifier)

GuaranteesIncrease in Mill Output % 10

Reduction in Specific Power kWh/t 1-1.5

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DescriptionBefore

ModificationAfter

ModificationImprovement

Classifier Size LSKS 92C LSVS 97C

Mill Output (t/h) dry 285 325 40 ( 14% )

Product Fineness cm2/g 3400 3400

Grinding Aid (g/t) Nil Nil

Total Specific Power(kWh/t) @Meter

(Mill + Fan + Classifier)

25.5 22.5 - 23.0 2.5 3.0

Comparative Operating Data

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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.

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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.

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04 Ravishankar Madras Cement Journey of Loesche Mills in Ramco Group

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