Ultratech Report Final

7/26/2019 Ultratech Report Final

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A REPORT

ON

AT

ULTRA TECH CEMENT LI M ITED.

UNI T: KOTPUTLI CEMENT WORKS

Submitted to- SUBMITTED BY

H.R. MANAGER TARUN MATHUR

Kotputli Cement Works M.B.M. Engineering College


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ABSTRACT

Cement, as used in construction, is a fine powder which when mixed with water

and allowed to set and harden can join different components or members together

to give a mechanically strong structure. Portland cement is the most common type

of cement in general usage in many parts of the world for construction purposes, as

it is a basic ingredient of concrete, mortar, stucco and most non-specialty grout. It

is a fine powder produced by grinding Portland cement clinker. The Portland

cement clinker is manufactured by igniting a finely ground mixture of lime bearing

material like CaCO3, clay, laterite in some predetermined proportions, cooling the

product of sintering. Grinding clinker by adding some proportion of gypsum, the

final product is called cement. The detailed description of each and every step in

the manufacture of cement is explained in the report. Also the equipment used in

every section, is explained in the report.

Cement manufacture involves grinding of clinker, gypsum, fly ash etc together.

For the manufacture of clinker raw materials should be burnt at high temperatures

of above 1400 degree Celsius in the kiln. To generate such large amounts of heat

fuels like coal, pet-coke or furnace oil are used. As these fuels are required in large

amounts, fuel costs play a major role in the operating costs of the cement plant. By

performing heat balance we can get specific heat consumption of the kiln, thereby

we can calculate approximate amount of fuel required. It also helps for stable

operation of kiln and optimization of kiln parameters. We can also study if thereare in any faults in the system from the calculations. The detailed description of

various terms in the heat balance calculations, procedure for heat balance,

necessary conditions and assumptions are explained in the report.


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ACKNOWLEDGEMENT

I am highly thankful to Solex Limited and Ultratech Cement Ltd--Kotputli forproviding me an opportunity to work in this industry and have such a great deal ofexposure to the cement industry. I would like to express my sincere gratitude to thefollowing people for their guidance and support:

Mr. Anil Vyas Sir,( HOD Chemical Engineering, M.B.M. College). Mr. B.R. Sharma Sir, (HOD Process). Mr. Sandeep Jalori Sir.(My mentor) Mr. Sitaram Sir.(Our instructor of solex limited)

And finally, I would like to thank every person of the staff who has helped medirectly or indirectly in the completion of my training.


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INTRODUCTION

ABOUT THE ADITYA BIRLA GROUP

A US $28 billion premium conglomerate, the Aditya Birla Group is in the league

of Fortune 500. It is anchored by an extraordinary force of 100,000 employees,

belonging to 25 different nationalities. In India, the Group has been adjudged The

Best Employer in India and among the top 20 in Asia by the Hewitt-Economic

Times and Wall Street Journal Study 2007. Over 50 percent of its revenues flow

from overseas operations.

The Group operates in 25 countries- India, UK, Germany, Hungary, Brazil, Italy,

France, Luxembourg, Switzerland, Australia, USA, Canada, Egypt, China,

Thailand, Laos, Indonesia, Philippines, Dubai, Singapore, Myanmar, Bangladesh,

Vietnam, Malaysia and Korea.

GLOBALLY THE ADI TYA BIRLA GROUP IS:

A metals powerhouse, among the worlds most cost-efficient aluminum and

copper producers.

No.1 in Viscose Staple Fibre

The 4

th

largest producer of insulators The 4

thlargest producer of carbon black

Among the worlds top 15 BPO companies

Among the most energy efficient fertilizer plants

Among the worlds top 10 cement producers


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IN INDIA:

The largest cement producer

A premier branded garments player

The 2nd

largest player in Viscose filament yarn

The 2nd

largest in Chlor- Alkali sector

Among the top 5 mobile telephony companies

A leading player in Life Insurance and Asset Management

Among the top 3 super-market chains in the Retail business

Rock solid in fundamentals, the Aditya Birla Group nurtures a culture where

success does not come in the way of the need to keep learning afresh, to

keep experimenting.

ULTRA TECH INDUSTRIES:

Ultra tech Industries Limited, a flagship company of the Aditya Birla

Group, ranks amongst Indias largest private sector companies, with

consolidated gross revenues of Rs. 148.33 billion and a consolidated net

profit of Rs.28 billion

Ultra techventured into the Cement production in the mid 1980s by setting

up its first plant at Khor in Madhya Pradesh. The merger of the Cement

business of Indian Rayon in 1988 and the acquisition of L&Ts Cementbusiness in 2004 catapulted the Aditya Birla Group to the top of the league

in India.

The Business has all its manufacturing locations in India except a packaging

and distribution operation in Sri Lanka which is part of Ultra Tech Cement


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Limited through its subsidiary, Ultra Tech Ceylino (Pvt.) Limited.

All plants are strategically located in the vicinity of sizeable limestone mines

and are fully automated to ensure consistent quality. All units employ state

of the art technology. All the cement units are certified with ISO 9001 for

quality systems, ISO 14001 for environment Management systems and

OHSAS 18001 Occupational Health and Safety Management System. Six of

its manufacturing locations are certified to SA 8000 Social Accountability

Standard

COMPOSITE PLANTS:

Vikram Cement, Jawad (MP)

Ultra tech Cement, Rawan (Chhattisgarh)

Aditya Cement, Shambhupura (Rajasthan)

Rajashree Cement, Malkhed (Karnataka)

UltraTech Cement, Reddipalayam (Tamil Nadu)

UltraTech Cement, Kotputli (Rajasthan)

UltraTech Cement, Awarpur (Maharashtra)

UltraTech Cement, Hirmi (Chattisgarh)

UltraTech Cement, Kovaya (Gujarat)

UltraTech Cement, Jafarbad (Gujarat)

UltraTech Cement, Tadipatri (AP)

Birla White, Kharia Khanghar (Rajasthan)


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GRINDING UNITS

Ultra tech Cement, Hotgi (Mahasrashtra)

Ultra tech Cement, Bhatinda (Punjab)

UltraTech Cement, Jharsuguda (Orissa)

UltraTech Cement, Durgapur (West Bengal)

UltraTech Cement, Arakkonam (TN)

UltraTech Cement, Magdala (Gujarat)

UltraTech Cement, Ratnagiri (Gujarat)

UltraTech Cement, Dadri (UP)

UltraTech Cement Aligarh (UP)

PRODUCTS

Clinker

Concrete

Various grades of Ordinary Portland Cement

Puzzolana Portland Cement

Sulphate resistant Cement

Portland Blast Furnace Slag Cement

White Cement

Wall Care Putty

BRANDS

UltraTechCement and Ready mix concret

Birla WhiteWhite Cement and its value added products etc


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UltraTech Cement, Kotputli

The date of announcement of UltraTech Cement, Kotputli Project was Friday, 31st

March, 2006. UltraTech Cement, Kotputli is a Greenfield project started in June

2006, under UltraTech Industries Ltd., of Aditya Birla Group having a capacity of

4.4 MTPA cement production. The cement plant is also equipped with Captive

Power Plant of 23*2 MW capacity. The Ultratech Cement, Kotputli is spread over

an area of 403.08 acre, and the mines area comprising of 888 acres of land.

Kotputli is located near Jaipur- Delhi Highway No.8.


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CEMENT

Cement can be defined as any substance which can join or unite two or more

pieces of some other substance together to form a unit mass.Cement, as used in

construction industries, is a fine powder which when mixed with water and

allowed to set and harden can join different components or members together to

give a mechanically strong structure.

The cements coming under the category of Portland cements are also known asHydraulic Cements, because they, when mixed with water, have the property of

setting and hardening under water.

PORTLAND CEMENTS

They are made by grinding a mixture of limestone and clay matter,

burning the mixture at a very high temperature, cooling the resultant product,

called Clinker, and grinding the same to an impalpable powder. Essential

constituents are lime, alumina, silica and iron oxide. Some gypsum is added in

the final grinding stages. Portland cement types are divided into seven classes,

but the method of manufacture is practically the same; they vary only in

chemical composition to impart desired properties.


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THE RANGE OF CHEMICAL COMPOSITION IS

SiO2 19-25%

Al2O3 2-8%

Fe2O3 0.3-6%

CaO 60-65%

MgO 1-6%

SO3 1-3%

Alkalies 0.5-1.5%

Table: Chemical Composition (Oxides) of clinker.

Portland cement types are essentially composed of Tricalcium Silicate

(C3S); Dicalcium Silicate (C2S), Tricalcium Aluminate (C3A) and Tertracalcium

Aluminoferrate (C4AF). Presence of more or less of the above constituents imparts

the different properties.

C3S 20-60%

C2S 20-60%

C3A 0-16%

C4AF 1-16%


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RAW MATERIALS

The main raw material used in the cement manufacturing process is limestone.Limestone is usually mined on site and most cement plants are located near thelimestone mines.

Other important raw materials are1. Clay

2. Red ochre

3. Laterite

Additives are also used for cement manufacture for improving properties ofcement.

1. Gypsum2. Fly ash

1. LIMESTONE :The chemical formula of limestone is CaCO3. It is mostly available in its purestform on the surface of the earth. When limestone is heated above 1100o C limeis formed,

CaCO3 CaO + CO2

This reaction is called Calcination reaction.

2. LATERITE :

It mainly comprises of non magnetic iron particles which acts as flux during theburning of raw material.

3. CLAY :

It contains silica particles required for clinker formation

4. RED OCHRE:

It is the main resource for alumina which again acts as flux material.

5. GYPSUM:

Its chemical formula is CaSO42H2O. It is used as additive during the grindingof clinker. The main advantage of gypsum is that it increases the setting time ofcement when it is mixed with water.


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6. FLY ASH: It is the additive used during the manufacture PPC. It acts asartificial Pozzolana. PPC gives high long term strengths

SIGNIF ICANCE OF INGREDIENTS OF CEMENT

C3S (Alite): contributes to early strength. Low heat of hydration compared to

alite.

C2S (Belite): contributes to late strength. Low heat of hydration compared to

alite

C3ASets quickly and increases heat of hydration

C4AFImparts a dark colour to the cement

TYPES OF CEMENT MANUFACTURED AT KOTPUTLI CEMENT

PLANT:

Ordinary Portland Cement43 grade

Ordinary Portland cement53 Grade

Portland Pozzolana cement


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CEMENT MANUFACTURING PROCESS


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MINING

Mining is mostly required for limestone and clay. Most of the cement plants aresetup close to a limestone mines because it is the major raw material in the cement

manufacture so that major transport costs are reduced. Mining of limestonerequires the use of drilling and blasting techniques.

The process of mining includes three things:1. Prospecting: It is the process of finding potential place where very useful &

bulk quantity of limestone can be extracted.

2. Drilling: After providing with a better place for mining, the process ofdrilling takes place, in which the place is drilled with the drilling machines,for inserting the dynamites.

3. Blasting: After drilling holes, this place is blasted by blasting materialsinserted inside the drilled part to break the huge rocks into pieces.

The blasting techniques use the latest technology to insure vibration, dust, and

noise emissions are kept at a minimum. Blasting produces materials in a wide

range of sizes from approximately 1.5 meters in diameter to small particles less

than a few millimeters in diameter. Material is loaded at the blasting face into

trucks for transportation to the crushing plant.


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CRUSHING

Raw material from mines in bulk transported and dumped into the hopper of thecrusher. In the crusher, the limestone is reduced to a size less than 50 mm.

Impact Crusher

The details of the crusher used in this plant are as follows:Make: Larsen and Toubro LtdModel: APCM-2022Capacity: 1600 TPD (with Wobbler feeder)Feed size: ~1.5m diaSize of Product: 90% (-) 40mm

Double Rotor Impactor giving precise control over product size.

Equipped with Vibrating Screen and Wobbler Feeder enhancing Crusheroutput.

Crushing circuit:

Limestone from mines is transported through Dumpers and dumped into hopper ofthe crusher. In hopper the material falls on to an apron conveyor. Apron conveyortransports the material on to a wobbler feeder. The wobbler feeder separates -50mm sized particles present in the feed so that only large sized particles are sent forcrushing. From wobbler feeder material goes into the impact section. Crushing of

material takes place in this section. Size reduction of material takes place byimpact betweeni.) Blow bar and material

ii.) Material and material

iii.) Material and impact arms.

The crushed material will have a size


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RAW MATERIAL HANDLING

Intermediate storage of raw materials between quarry and the raw mill.Used as pre homogenization or pre-blending.

Capacity of stacker1600Tph

Capacity of reclaimer1200 Tph

i . STACKING :

The percentage of limestone in raw material which is quarried from the minesvaries because every part of the mine cannot have same amount of limestone

percentage everywhere. So at the stackers the limestone is homogenized by

arranging the raw material in proper stock piles before sent to raw mill for grinding

TYPES OF STACKER:

1. Slewing and luffing stacker> For coal.

2. Non slewing and luffing stacker-

> For limestone and additives.


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ii. RECLAIMERS:

Reclaimers are used for the transportation of raw material to the respective mill

hoppers. All the raw materials are stored in various stock piles and reclaimed

whenever required.

Machine which removes material from stockpiles.

Used for transportation of raw material to the raw mill hopper.

ADVANTAGES :-

Homogenizing of non-homogeneous material.

Better utilization of inhomogeneous raw materials deposits.

Pre blending of different raw material component is possible.

Better uniformity of raw mill and thus of the clinker, so quality of cement is

constant.


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RAW MATERIAL GRINDING

RAW MI LL HOPPERS

From stacks the raw material is transported to raw mill hoppers with the help ofreclaimers. In this plant there are 5 raw material hoppers of different capacities of

which 2 are for lime stone, 1 for clay and 2 metallic hoppers for laterite and red-ochre each.From here raw material is sent to raw mill where it is ground to very fine particles.

Desired proportions of the raw materials are sent to the mill by using weigh-

feeders. Weigh-feeders calculate the amount of each material from the percentage

of material specified to it. The proportion of raw mix is determined by the Quality

Control department of the plant. From weigh-feeders the material is transported

into raw mill through conveyor belts.

From stacks the raw material is transported to raw mill hoppers with the help

of reclaimers.

In our plant 5 raw mill hoppers are there, 2 for limestone and one each for

clay, laterite and red-ochre each.

From here desired proportions of raw material are send to the raw mill

through weigh feeders via conveyor belts.


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RAW MILL


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Process of raw mill

In our plant the equipment used for grinding in raw mill is vertical roller

mill.

The material from raw mill hopper comes to raw mill through conveyor belts Feed is introduces from the top on the grinding table.

Retention ring on the periphery forms the grinding bed.

Hot air from the bottom lifts the material to the classifier which is located at

the top of the mill

Classifier separates coarse and fine particles.

Fine product moves out of the classifier with the air discharge.


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BLENDING SILO

Known as BLENDING SILO

Capacity31200 MT

Height78.5 mtr

Diameter26 mtr

Last stage of homogenization

Used for storage of raw meal

There are 14 air slides at the top which carry the raw meal to the silo and 12

at the bottom to convey the material further to the pyro processs.


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COAL MILL

Imported Coal and Pet-coke are the main fuels used for burning purposes. Both ofthem are ground to fine powder in the coal mill. Petcoke is the industrial byproductof petroleum industries. It has very high calorific value around 8300kcal/kgcompared to coal. But the grinding of petcoke is difficult when compared to coal.Lot of heat is generated during grinding of petcoke so it is somewhat difficult

process. In India mostly coal is used as fuel. For burning of raw mix the ashcontent in the coal should be as less as possible because more ash% in coal affectsthe color of the cement becomes darker and affects the cementatious properties.In this plant VRM is used for fuel grinding.

Main points:

Main fuel used is imported coal and pet coke for burning purpose.

In coal mill, coal/ pet coke is grounded into fine coal for firing in precalciner

and kiln.

Coal mill also dry up the moisture in raw fuel through the heat of hot kiln

flue gases.


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Has one type of accumulatorBladder Type ( 4 in number) for handling the

operating pressure.

COAL MILL FLOW DIAGRAM


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PYROPROCESS

In the latest cement industries the pyroprocess consists of 3 sections:1. Preheater

2. Burning in a rotary kiln

3. Cooling of clinker formed


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Preheater:

Preheater is the latest technology used in the field of cement industry to

decrease the time of burning in the rotary kiln for the formation of clinker,

so that the production of Clinker is increased. A preheater is long verticaltower consisting of cyclone separators connected in series from top to

bottom and also precalcination tower is arranged as latest Development. For

the formation of clinker the raw mix should be burnt to a temperature of

above 1200oC. Without preheater it takes a long time to achieve this

temperature in the kiln making the retention time of material is very high

hence production of clinker is very low. But with the use of preheater, this

temperature is achieved very fast thereby increasing the production of

clinker to a large extent. Heating of material in preheater is done by hot exitgases of kiln and hot gases generated from cooler.

Make: KHD-GermanyType: 6-stage Preheater with calciner (2 strings)

Capacity: 10000 TPD


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Preheater Material Flow:

In preheater material is introduced from top and hot gases are blown from bottom.A draft fan placed after preheater tower creates suction and regulates the flow ofgas. The raw meal is normally introduced at the riser duct of stage (2)-(1). The

material is dispersed into the rising gas stream, ensuring an instantaneous heattransfer. Due to suction the material and the hot gases are lifted up into cyclonestage (1). Velocity in the riser duct is maintained in such a way that material is not

dropped down. In the cyclone air and material are separated and material leaves thecyclone from bottom cone. It flows through the material flap gate and is 26directed to riser duct of stage (3)-(2) and the process repeats. Major heat transfer

between material and hot gases takes place in the riser ducts. In this manner the

material passes step-wise through the cyclones while heat exchanging with the hot

gas.

From the cyclone stage (5) the material is directed to the calciner. The material willbe suspended in the gas while the calcination process takes place. This ensures an

excellent mixing and transfer of heat. From the calciner top the material and gas

enters the bottom cyclone stage i.e., stage (6) where material and gas are separated.

The exit of stage (6) is connected to the kiln inlet. The inlet temperature of material

entering kiln would be around 1100oC. Upon leaving the last stage the material

should normally have a degree of calcination of between 90-95%.


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KILN

Make : KHD

Length : 85 m

Diameter : 5.8 m

Speed :4.5 rpm

Specific heat consumption : 686 kcal /kg

Number of supporters : 3

Inclination : 3.5%

Function :to produce clinker

There are 4 zones

Calcination zone

Transition zone

Burning zone

Cooling zone


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CALCINATION ZONE:

Endothermic reaction.

In this calcium carbonate decomposes to form quick lime and carbon

dioxide. Temperature required is around 900 degrees Celsius.

In this zone calcination completes.

TRANSITION ZONE

Endothermic reaction

Temperature around 1200 degree Celsius.

Formation of belite, Tri calcium aluminate and Tetra calcium alumino ferrite

in this zone. Without the formation of fluxing reagents i.e. C3A, C4AF the formation of

alite would be slow and difficult.

CHEMICAL REACTIONS :-

2Cao + Sio2 C2S (2CaO.SiO2)

3CaO + Al2O3 C3A

4CaO + Al2O3 + Fe2O3 C4AF


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BURNING ZONE

Also known as HEATING ZONE.

Temperature is around 1300- 1450 degree Celsius.

Tri calcium silicate is formed.

process completes when all the silica is in C3S and C2S crystals and the

amount of free lime (CaO) is reduced to minimum level ( less than 1%).

CHEMICAL REACTIONS :-

COOLING ZONE

Cooling of clinker takes place in this zone by coolers.

Temperature of clinker is reduced to nearly 100 degree Celsius.

Cooling process influences clinker structure, composition grind ability, thus

quality of cement.

Rapid cooling increases sulphate resistance, prevents undesired chemical

reactions in clinker which may affect quality and grind ability.

These reactions happen at different temperatures in preheater and kiln. A glance ofclinkering reactions is given below:

i.) Up to 700oC: At 100oC free moisture in raw meal is removed due to evaporation.

400 C -500 C combined moisture is removed

Clay minerals are decomposed into their oxides (SiO2)

ii.) From 700-900 oC: Calcination continues, CaCO3 dissociates to CaO, free lime increases.

Calcination maintains feed temperature around 850oC.

Lower limited aluminate and ferrite form


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iii.) From 900-1150 oC :

Reactive Silica combines with CaO to begin formation of C2S.

iv.) From 1150-1200 oC :

Calcination is completed

Small belite crystals form from combination of silica and CaO.

v.) From 1250-1350 oC :

Above 1250C liquid phase is formed

Belite and CaO form Alite in the liquid

vi.) From 1350-1450 oC

C2S crystals decrease in number and increase in size C3S crystals increase in size and number

vii.) Cooling :

Upon cooling C3A & C4AF crystallize from liquid phase


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The raw meal enters the top of the kiln, which is slightly inclined

downwards. The material is transported through kiln by the combination ofkiln inclination and rotating movement. The kiln speed is normally

maintained around 4.5-5rpm. Kiln has 3 zones namely Calcination zone,

Burning zone and Cooling zone. In calcination zone total calcination

reaction is completed. The formed lime starts reacting with silica, alumina

and iron oxide to form clinker. In the burning zone the flame heats the raw

meal to 1400oC in order to complete the clinkerisation process, producing

clinker. The cooling zone is very small where the cooling and solidification

of formed clinker starts and material is directed into cooler for final cooling.


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COOLER

Cooling of clinker is essential before storage. A cooler is used for this purpose and

the temperature of clinker is reduced nearly to 100oC at cooler exit. In this plant a

pyrofloor cooler is used for cooling purpose. This is the most advanced clinker

cooler in the field of cement industry. In addition, rapid cooling prevents undesired

chemical reactions in the clinker which may negatively affect the quality and the

grind ability of the clinker.

Make : KHD Germany

Type : Pyro floor cooler

Dimensions : length- 47.8m,width4.09 m

Lanes7

Number of fans11


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In cooler there are lanes placed parallel to each other. Hot clinker from kiln

falls onto these lanes. The lanes move forward and backward in a systematic

way so that the clinker conveyed forward. Cool air is blown from the bottom

by the cooler fans. There are 10 cooler fans installed in this plant. As the

material moves forward cool air is blown from bottom and in this clinker is

cooled. The hot air generated after cooling the clinker is sucked into kiln and

TADs for further heating purposes in preheater, raw mill by the draft fans

placed after preheater exit. The exhaust gases are sucked by a cooler draft

fan and sent to electrostatic precipitator to separate dust from hot air before

sent into stack. The draft fan is placed after the exit of electro static

precipitator. The collected dust is again sent to clinker conveyor. Required

amount of air is sent into cement mills for heating purposes from the stack.


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CLINKER SILO

After cooling, the clinker turns into strong hard balls around 100-130oC. Thisclinker is sent to clinker silo for storage. Bag filters are arranged for the collectionof emitted dust during transportation into the silo.

Design : Peters Silo

Capacity: 1.5 Lac MT * 1 Silo


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CEMENT MI LL

MAKE: Loesche, Germany

SPECIFIC POWER CONSUMPTION : 40 kWh/T

MODEL : LM 53.3 +3 (VRM with 3 master and 3 slave rollers)

CAPACITY : 215 TPH

NUMBER OF MILLS : 2

FEED SIZE : 85%


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Clinker from silo is transported to cement mill hoppers. There are other hoppers

for gypsum, wet fly ash and dry fly ash which are used as additives during grinding

of clinker. Required proportions of materials is measured through weigh-feeders

and sent to the mill for grinding. Here also a vertical roller mill is used for grinding

of clinker. The grinding of clinker to cement is a dry grinding process. It is to be

noted that the temperature of clinker coming out of cooler may be near about

100oC and temperature doesnt go down much in storage and during grinding a

considerable amount of heat is generated. It is not desirable to allow the

temperature of cement above 120oC and preferably it should be below 100oC.


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CEMENT SI LO

After grinding the formed cement is transported to cement silos through air slides

for storage. There are 2 cement silos in the plant having 3 compartments each.

Design: 3 compartment siloCapacity: 15000 MT each silo

In KCP there are two cement silos.

Each silo have capacity of 15000 tones.

Total capacity of cement storage is 30000 tones.

Each silo has 3 compartments.

Silo 1 : 2 compartments of PPC

1 compartment of OPC 43

Silo 2 : 1 compartment of PPC

1 compartment of OPC

1 compartment of OPC 53


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PACKING AND DI SPATCH

The cement is transported into packing plant where the packing and dispatch ofcement takes place. The cement packed into plastic bags with help of packingmachines. There are a total of 8 packing machines in the packing section.

It consists of:1. Storage of element in silo.

2. Silo extraction system.

3. Packing of cement in bags.

4. Truck loaders.


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Cement Loading Capacity: 12000 MT/ Day

Packers :Make: EEL

Model: Roto Packer 6 RS-E(Electronic Packers)Capacity: 90TPH @ 3800 Blaine

No of Packers: 8Other machines in the packing section are:

Trailer Loading MachineMake: BeumerModel: B-18Capacity: 90 TPH

No of Machines: 14

Truck Loading MachineMake: EEL

Model: TLM 1020 J/BCapacity: 90TPH

No of Machines: 2


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FLOW DIAGRAM OF CEMENT SI LO AND PACKING


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PROCESS OF CEMENT PACKING


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Bulk Transport

Clinker is also bulk transported. From silo clinker is sent to the bulk loading

section via bucket elevators and conveyor belts. There are 2 silos in the bulkloading section. Clinker from silo is directly dumped into the trucks.The details of the section are:Make: DCL Bulk Technologies.

Clinker Hopper Capacity: 700 MTClinker loading capacity: 7200 TPD

Other important points are Two loading points

Stationary weighbridges at loading points enabling simultaneous loading andweighing of trucks.

Equipped with dustless loading spouts so that no dust emission duringloading.

No reverse movement of trucks.


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PROJECT ONHEAT BALANCE


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INTRODUCTION OF HEAT BALANCEIn Kotputli cement works dry process kiln system is used. The feed materials are

preheated by the hot gases from rotary kiln. A secondary burner is included toimprove energy efficiency. The mixture of the preheated and precalcined materials

enters the kiln, which is a counter flow reactor. Fuels together with air enter from

the opposite end. The solid feed is heated to an extremely high temperature in the

burning zone such that raw materials react and form clinker. Clinker exits the kiln

at about 1400 degree Celsius and is cooled down to less than 150 degree Celsius by

flowing air. Part of the heated air from the cooler enters the kiln, another portion

flows to the pre-calciner, the rest is gone to preheater by two tertiary air Ducts.

Diagram showing flow in preheater, kiln and cooler


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REASON OF HEAT BALANCE

The main purpose of heat balance is to find the Specific Heat consumption

of kiln system through fuel which is used for burning.

Heat Balance calculation is basically a calculation where heat inputs andoutputs are measured, calculated and compared.

We can yield information about where heat losses occur in the system.

Helps to study the system and diagnose any problems in it.

With this information the plant personnel can decide if any action is required and

identify the points where attention might be needed.

NECESSARY HEAT BALANCE CONSIDERATIONS:

For achieving a good heat balance following considerations should be followed:

The best way to secure a reliable result in heat balance is by ensuring that

the kiln operation is reasonably constant during the period of measurement,

at least 2-3 days. The measurements should reflect average values over a

time span of 8 hours.

To make proper balance it is necessary that all the figures are measured /

calculated individually.

For a heat balance to be reliable it is necessary that the inputs and outputs

established balance within a reasonable degree of accuracy; normally within

2-4% relative. A better result cannot be expected due to limitations on

accuracy of all the individual measurements.

It is important to establish the clinker production with high degree of

accuracy, as it forms basis for many of the calculations. Often plant uses an

approximate value for the kiln feed to clinker factor for estimating clinker


47/78

production. This is often not accurate enough for a heat balance calculation,

so, the clinker must be either weighed or chemical analysis can be done.

The most reliable method is by weighing the clinker production

during the heat balance performance. This can be done on a weighing

bridge. The period required for obtaining a reliable result will often be

approximately 24 hours. If a smaller time span is used, the small

disturbances taking place, such as kiln going cold or hot, or the clinker layer

increasing or decreasing in the grate cooler, will greatly affect the weighed

production and introduce large errors.

All measurements carried out in the course of heat balance should ideally be

performed simultaneously. As this is seldom practically possible, it is

advantageous to identify those heat losses that can be considered almost

constant during the time in which measurements are taken and average

values can be used for the heat balance.

Highly variable and closely connected values must be measured as

simultaneously as possible to get consistent results. Typically connected

values in this sense include surface heat loss from cooler, clinkertemperature, preheater exit gas temperature and exit gas composition.

The magnitude of the various heat losses that enters into the heat balance is very

different. For instance the surface heat loss from a cooler will be approximately 5-

6 kcal/kg clinker while heat losses with excess air from a cooler will be as high as

120 kcal/kg clinker. The higher the value, the more important it becomes to ensure

that the value is correct and that measurement is reliable. The error that can be

caused by estimating surface loss is relatively small compared to the unavoidablemeasuring errors when determining the excess air


48/78

METHOD OF CALCULATION

The main method of calculation is to consider the kiln as a system and then

calculating the Heat entering and heat leaving from the system. Pyro Section

consists of preheater, cooler and rotary Kiln so there are various heat inputs,

losses and outputs are going on. For this, Kiln is considered as a system and

heat balance is done.

Second step is to choose the reference temperature for the calculation of

sensible heats.

Third step is to define input and output material flows. Input include raw

meal , the fuel and the air. Outputs are smoke gas. The dust with the gas,etc.

Some other sources include heat of reaction of raw meal, latent heat,

sensible heat, and convection and radiation losses from surfaces.

Now the final result is calculated in kcal/kg clinker.


49/78

EQUIPMENT USED

Various equipments are used to do the heat balance in kiln .Because for finding

out heat Inputs and outputs the temperature, pressure, flow, specific heat, are some

of the things that Have to be known. Some equipments names are given below:

Pitot tube -It is used to find static and dynamic pressure of the flow. We can

find out the difference between the pressure of two points and the pressure at a

single Point. It is very important for measuring the mass flow rate of gases and

feed Mass flow rate is then used to find heat coming or liberated. For calculatinggas velocities S-type Pitot tube is used. Pressures are measured using a digital

pressure meter.

In the case of Pitot tube the value of c taken to be .83.


50/78

ThermocoupleIt is used to measure the temperature that is very important

for measuring heat inputs and outputs. By the use of temperature and pressure we

can also find out the density which helps in finding flow rate.

Anemometer- It is used to find the velocity of air fans which are used in the

calculation of heat conveying into kiln through air. By this we can directly measure

velocity of fans. For measuring Cooler fan velocities a thermal anemometer isused.

TERMS USED:

Specific heat: It is the amount of heat per unit mass required to raise the

temperature by one degree Celsius. The relationship between heat andTemperature change is usually expressed in the form shown below where cis the specific heat.

Q = Where q is the heat added or removed

Unit = KJ/kg


51/78

Latent heat -latent heat is the heat released or absorbed by a body or a

thermodynamic system during a process that occurs without a change in

temperature. For example phase transition such as melting of ice or the

boiling of water.

Q = mL

Where L is the latent heat for a particular substance

Unit = KJ

Sensible heatIt is heat exchanged by a body thermodynamic system that

has its sole effect a change of temperature. the sensible heat of a

thermodynamic process may be calculated as the product of the bodys mass

(m) with its specific heat capacity(c) and the change in temperature same as

specific heat.

Heat of reactionit is the amount of heat that must be added or removed

during a chemical reaction in order to keep all the substances present at the

same temperature. If the pressure in the vessel containing the reacting

system is kept at a constant value, the measured heat of reaction also

represents the change in the thermodynamic quantity called enthalpy.

Calorific Value (CV):The calorific value or heating value of a

substance, usually a fuel or food, is the amount of heat released during the

combustion of a specified amount of it. The calorific value is a

characteristic for each substance. It is measured in units of energy per unit

of the substance, usually mass, such as: kcal/kg, kJ/kg, J/mol, Btu/m.


52/78

1.SURFACE LOSS:

There are two types of heat loss from surfaces, namely convection andradiation.

Total surface loss = convection loss+ radiation loss

CONVECTION LOSS:It is the measure for heat escaping due to

cooling effects of surrounding air temperature. It will increase with

increase in movement of wind (wind speed). Air acts as medium of

heat transfer. Heat transfer takes place from higher temperature areas

to lower temperature areas.

RADIATION LOSS:It is the heat escaping the surface through radiation. It

depends on the surface temperature and emissivity of the material


53/78


54/78

TABLE SHOWING HEAT INPUTS AND OUTPUTS

Heat inputs Heat outpu ts

Heat with kiln feed Heat of reaction of raw materials

Heat by air from cooler Heat from exhaust from kiln

Heat of Combustion Heat loss by dust

Heat by primary air Radiation and convection losses

Heat from moisture in feed Cooler water spray evaporation

Cooler air Heat from clinker out

Cooler water spray Preheater and cooler exhaust air


55/78

SOME BASIC FORMULAS

1. Specific Heat calculation:

2. Fan Formulae:

a.Flow at operating conditions:

Fop = Cross-section area (or) Suction area * Velocity of air (or) gas m3/hr

b.Normal density of gas = (%gas/100)*Mol.wt/22.4 kg/Nm3

Mol.wtMolecular weight

c. Operating density =Normal density*((9884+PS)/(273+Top))*(273/10333)

kg/m3

9884 mmwg is the barometric pressure at sea level

PSStatic Pressure, mmwg

TopOperating Temperature,oC

d. Velocity of gas = m/sCPitot-tube constant, [here C = 0.83]

PDynamic pressure, mmwg

gacceleration due to gravity, m/s2

Operating Density, kg/m3

e. Mass flow:

Mf= kg/hrFopFlow at operating conditions, m

3/hr

Operating Density, kg/m3


56/78

3. Sensible Heat:

Q = kcal/kg clinkerm: Specific mass, kg/kg of clinker

Cp: Specific heat capacity, kcal/kg-oC

Tbody: Temperature of the body,oC

Treference: Reference Temperature,oC

HEAT INPUTS:

There are various heat inputs in the kiln. They are calculated per kg clinker. These

are explained below:

heat by raw material

Q = mcHere m is the mass of the feed per kg clinker

C is the specific heat

And delta T is the difference in temperature

heat by primary air

Primary air consists of three types of air

Jet airto provide length to the flame

Swirl airto provide width to the flame

Cooling airto cool the burner

Heat by air from cooler: This air is also known as secondary air. It is

transported from Cooler to preheater through kiln and considered as a heat input.

This can be considered as a way to minimize waste air and calculated with formula

mc


57/78

Heat of combustion:Heat of combustion of coal should also be taken into

account for Heat input. Because in Kotputli cement plant we are using two types of

fuels

Imported coal : Ii is mainly imported from south Africa. The composition

of this coal is taken to be 38% in the coal feed in Kotputli cement plant.Its

Calorific value is 6100 kcal/kg

Pet coke : It consists of fly ash also. The composition of pet coke in kcw

is taken to be 62%. Its calorific value is 7900 kcal/kg

Note : Pet coke percentage is higher than imported coal because: Pet cokes calorific value is very higher than imported coal

It is very cheaper than imported coal because it also consists fly

ash and generated here.


58/78

HEAT OUTPUTS

Heat that is coming out of the kiln can be divided into following parts:

Heat of reaction: Heat of reaction can be calculated by the formula

4.11(Al2O3) + 6.48(MgO) + 7.646(CaO)5.1165 (SiO2) - .59(Fe2O3)

Where when we put the percentages of these compounds present in clinker we getthe heat of reaction.

Radiation Loss:The temperature of inside of kiln is very high. To prevent

radiation losses Refractory bricks are put inside the shell but then also kiln shell

temperature is very high. Due to the difference in temperature between kiln shell

and surrounding due to radiation heat Loss takes place. In preheater, tertiary air

ducts and cooler also loss is to taken into account. All cyclones have differenttemperatures so that also have to take into account

Radiation Loss = /(1000 * m)Here is the Boltzmanns constant (5.67 * 10^-8)

Is the emissivityA is the area

M is the mass of clinker in kg/hr


59/78

Heat taken away by clinker: clinker that goes to the cooler from the kiln takes

is also at a high temperature of around 1250 degree Celsius. For calculating heat

due to it mass is taken to be 1kg/kg clinker and specific heat is calculated.

Heat taken by dust:The dust particle that moves from kiln to the preheater

also takes away some heat with them that is also taken into account. For

calculation purpose it can be considered as a constant.

Heat of moisture in input: Feed that is coming to the kiln also brings some

moisture with it this moisture has to be evaporated in order to complete dry

process. This can be calculated by the formula

Q = mL + mc

Heat of moisture in coal:The coal that is used for burning zone also bringssome moisture with it and to evaporate it is necessary. We have to consider both

pet coke and imported coal in it as their percentage in coal feed is different same

formula as stated above is used for calculating.

Heat of convection: convection losses are also there present in the kiln which

can be Calculated in kcal/kg clinker by the below represented formula

80.33 *


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Where 80.33 is constant

A is the surface area of the kiln

T inside is the temperature inside of pyro section

T surrounding is the temperature of the atmosphere

Clinker production in kg/hr

SOME MEASUREMENTS


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Specific heat data

String-1 PH fan % Density A B C Temp(oC) Sp. heat

CO2 30.0 0.59 0.196 118 -43 258 0.07

H2O 4.00 0.03 0.443 39 28 258 0.018

N2 59 0.74 0.244 22 0 258 0.148

O2 6.8 0.10 0.218 30 0 258 0.015CO 0.00 0.00

Total 100.0 1.46 0.248

String-2 PH fan % Density A B C Temp(oC) Sp. heat

CO2 30.0 0.59 0.196 118 -43 266 0.07

H2O 4.00 0.03 0.443 39 28 266 0.018

N2 60 0.75 0.244 22 0 266 0.150

O2 5.9 0.08 0.218 30 0 266 0.013

CO 0.00 0.01

Total 100.0 1.46 0.249

Air (cooler) ESP

exhaust 1.29 0.237 23 0 272 0.243Kiln feed 0.206 101 -37 78.4 0.214

Clinker 0.186 54 0 108 0.192

Fine Coal 0.262 390 0 67 0.288Kiln feed return dust 0.206 101 -37 262 0.230

Air (Cooler fan) 0.237 23 0 19 0.237

Air (PA blower) 0.237 23 0 65 0.238Air (PA fan) 0.237 23 0 20 0.237

Air (coal feed) 0.237 23 0 55 0.238

Air secondary 0.237 23 0 1120 0.263Air tertiary-1 0.237 23 0 865 0.257Air tertiary-2 0.237 23 0 896 0.258

Hot clinker 0.186 54 0 1400 0.262

Cooler water spray 0.443 39 28 19 0.444Kiln feed moisture 0.443 39 28 262 0.455

Density of flue gas 1.46


62/78

1. TEMPERATURES AT VARIOUS POINTS:

PointoC

Air (cooler) ESP O/L 272Raw meal Kiln Feed 78.4

Clinker cooler discharge 200

Fine Coal 67

Raw meal return dust 250

Air (Cooler fan) 19

Air (Primary Air blower) 65

Air (PA fan) 20

Air (coal feed) 55

Air secondary 1120

Air tertiary 900

Hot clinker 1400

2. CLINKER COMPOSITION:

Composition of clinker should be taken on the same day of doing heat

balance. Clinker composition can be acquired from the Quality Control

department of the plant.

Oxide Symbol %

SiO2 (S) 20.95

Al2O3 (A) 5.22

Fe2O3 (F) 4.35

CaO (C) 62.21

MgO (M) 4.85


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3.BLOWERS AND FANS:

Blower/Fan Temperature(oC)

Static Pressure(mmwg)

Burner cooling fan 20 622

Jet air blower 65 7003

Swirl air blower 20 179

Pyroclon1 blower 44 2131

Pyroclone2 blower 45 2516

LowNOx blower-1 54 3910

Kiln Coal conveying

blower44 2271


64/78

C.S.

length Area

T1

(0C)

T1

(0K)

0-1 18 300 573

1-2 18 285 558

2-3 18 280 553

3-4 18 275 548

4-5 18 270 543

5-6 18 240 513

6-7 18 120 393

7-8 18 150 423

8-9 18 220 493

9-10 18 200 473

10-11 18 220 493

11-12 18 220 493

12-13 18 200 473

13-14 18 210 483

14-15 18 260 533

15-16 18 300 573

16-17 18 300 573

17-18 18 300 573

18-19 18 300 573

19-20 18 300 573

20-21 18 150 423

21-22 18 150 423

22-23 18 150 423

23-24 18 145 418

24-25 18 150 423

25-26 18 300 573

26-27 18 325 598

27-28 18 340 613

28-29 18 330 603

29-30 18 310 583

30-31 18 310 583

31-32 18 300 573

32-33 18 250 523

33-34 18 200 473

34-35 18 300 573

35-36 18 280 553

36-37 18 300 573

37-38 18 295 568

38-39 18 300 573

39-40 18 310 583

40-41 18 315 588

41-42 18 310 583

C.S.

length Area

T1

(0C)

T1

(0K)

42-43 18 310 583

43-44 18 300 573

44-45 18 260 533

45-46 18 250 523

46-47 18 255 528

47-48 18 260 533

48-49 18 255 528

49-50 18 255 528

50-51 18 260 533

51-52 18 260 533

52-53 18 265 538

53-54 18 260 533

54-55 18 270 543

55-56 18 260 533

56-57 18 260 53357-58 18 265 538

58-59 18 260 533

59-60 18 255 528

60-61 18 200 473

61-62 18 130 403

62-63 18 240 513

63-64 18 230 503

64-65 18 225 498

65-66 18 200 473

66-67 18 150 423

67-68 18 135 408

68-69 18 200 473

69-70 18 205 478

70-71 18 210 483

71-72 18 225 498

72-73 18 235 508

73-74 18 235 508

74-75 18 230 503

75-76 18 230 503

76-77 18 230 503

77-78 18 225 498

78-79 18 225 498

79-80 18 220 493

80-81 18 210 483

81-82 18 200 473

82-83 18 145 418

83-84 18 110 383

84-85 18 100 373


65/78

Above table indicates the temperatures of kiln shell at surrounding temperature

313 degree kelvin.

CALCULATIONS

HEAT OUTPUTS

Heat of reaction

Material percentage

Al2O3 5.22

Fe2O3 4.35

CaO 62.21

MgO 4.85

SiO2 20.95

Q = 4.11 x A + 6.48 xM + 7.646xC - 5.1165xS - 0.59x F

= 418.783 kcal/kg

Heat in clinker out

Q = mc ()(1 kg/kg clinker) * 0.192 kcal/kg* (2000)

= 38.4 kcal / kg clinker

Heat of moisture in input

Moisture % in feed = 0.16

Total input feed = 648 Tph


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Total moisture in input = (0.16 / 100) *648 *1000 =1040 kg/hr

So, in 1 kg clinker moisture is = (1040 /405000) = 0.0025 kg/hr

Heat of moisture = mL + mc= 0.0025 * 597 + 0.0025 * 0.5 *(2500)

= 1.805 kcal/kg of clinker

Moisture with coal

Pet coke percentage = 62 %

Imported coke percentage = 38 %

Let total coal consumption = X

Pet coke moisture = .7 %

Moisture in imported coal = 1.98 %

Total moisture in coal is = (.62 * .007 * X) + (.38 * .0198 * X)= .01184X kg/kg clinker

So, heat of evaporation in coal moisture= (.01184X)*597 + (.01184X)*(.5)*(67-0)

= 7.29 X

Heat loss by dust

Percentage of dust in feed = 4 %

So, dust present in feed = 4 % of 648 Tph = 26 Tph

So, per kg of clinker = (26 / 405) = 0.064 kg/kg clinker


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Q = mc= 0.064 * 0.23 * (262-0) = 3.85 kcal/kg

Heat loss by radiation

1. by kiln shell:

Q = / (1000 * m)= {4.87 * 10 ^ (-8) * 3.14 *85 *5.8*(513^4313 ^4)} / (1000*405)

= 11.11 kcal/kg clinker

Heat loss by convection

= 80.33 *

= [80.33 *(3.14*85*5.8) *{(513+313)/2} ^ (-.724) * (513-313) ^

1.33]/(1000*405)

= 4.576kcal/clink

Note: Radiation and convection losses from preheater, tad and cooler is

taken to be 35 kcal/kg clinker

Heat in preheater exit gasesTotal Kiln feed 648 TPHClinker output 405 TPHClinker output 405000 kg/hr

a) String-1 Preheater


68/78

Fan

Total Gas flow 641645.0 m3/hr

Total Gas flow 420756.5 kg/hrSpecific mass (m) 1.039 kg/ kg clinkerCp 0.248 Kcal / Kg

oC

Gas temp. 258.0

o

C

Qa= 66.6

Kcal/Kg of

clinker

a) String-2 PreheaterFanTotal Gas flowDensity

664563.91.54

m3/hr

kg/ m3

Total Gas flow 428823.3 kg/hr

Specific mass (m) 1.059 kg/ kg clinker

Cp 0.249 Kcal / KgoCGas temp. 266.0

oC

Qb= 70.1

Kcal/Kg of

clinker

(Qa+ Qb = Q= 136.7

Kcal/Kg of

clinker

Heat in cooler exhaust air

Kiln feed 648 TPHClinker output 405.00 TPH

405000 kg/hrGas flowDensity

827386.61.62

m3/hr1.62kg/ m3

Mass flow rate 509652.5 kg/hrSpecific mass (m) 1.3 kg/kg of clinkerCp 0.243 Kcal / Kg

oC

Q= 83.3

Kcal/Kg of

clinker


69/78

Heat of cooler water spray evaporation


405000.0 kg/hrWater spray in cooler 5.6 KL

5600 Kg

sp. Masstempspecific heat

0.013190.444

kg/kg of clinker

Kcal/kg

Heat loss for coolerwater spray 10.2

Kcal/Kg of

clinker

Heat inputs Heat with kiln feed = mc()

= (648/405) * 0.260 *(90-0)

=37.55 kcal/kg clinker

Heat of combustion

Q = calorific value * mass of fuel

= CV * X

Mass of pet coke = .62X

Mass of imported coal = .38X

Calorific value of pet coke = 7900 kcal/kg

Calorific value of imported coal = 6100 kcal/kg

Q = 7900*.62X + 6100 * .38X

= 7216X


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Heat by primary air

i) Jet airTemp. 65

oC

Air density 1.7027 kg/m3

Air flow 5724.2 m3/hr.9747.11 kg/hr.

air specific mass(m) 0.024 kg/kg clinkerCp 0.24 Kcal / Kg

oC

Q1= 0.37Kcal/Kg of

clinker

ii) Swirl air

swirl air dia 250 MmArea 0.05 m

2

Air velocity 6.04 m/secTemp. 20

oC


air flow 0.30 m3/sec

1066.9 m3/hr

1248.9 kg/hrair specific mass(m) 0.003 kg/kg clinkerCp 0.237 Kcal / Kg

oC

Q2= 0.01Kcal/Kg of

clinker

iii) Burner coolingairTemp. 20

oC


air flow 1861.8 m3/hr.

2275.2 kg/hr.


oC

Q3= 0.03Kcal/Kg of

clinker

iv) Kiln Coal

conveying air


71/78

Temp. 44.00oC


Air flow 6084.2 m3/hr

7948.7 kg/hrair specific mass(m) 0.0196 kg/kg clinkerCp 0.2385 Kcal / KgoC

Q4= 0.21Kcal/Kg of

clinker

v) PC Coal conveying air -1Temp. 44

oC



7887.2 kg/hr


oC

Q5= 0.20Kcal/Kg of

clinker

vi) PC Coalconveying air -2Temp. 45.00

oC


Air flow 6059.3 m3/hr8052.7 kg/hr

air specific mass(m) 0.020 kg/kg clinker

Cp 0.238 Kcal / KgoC

Q6= 0.21Kcal/Kg of

clinker

vii) LOW NOX CoalConveying air-1

Temp. 54o

CAir density 1.44 kg/m

3


9641.1 kg/hrair specific mass(m) 0.024 kg/kg clinkerCp

Kcal KgoC


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Q7= 0.31Kcal/Kg of

clinker

Total Q =Q1 + Q2+Q3+Q4+Q5+Q6+Q7

Q = 1.34Kcal/Kg of

clinker

Heat in clinker cooling air

Temp = 19 degree Celsius

Specific mass = 2.39 kg/kg of clinker

Cp = .237 kcal/kg

Q = 10.8 kcal/kg of clinker

Cooler water spray


405000.0 kg/hrWater spray in cooler 5.6 KL

5600 Kgsp. Mass 0.013 kg/kg of clinkerSpray water

temperature 19oC

Heat by cooler waterspray 0.109

Kcal/Kg of

clinker

Sensible heat of fuel

specific mass (m) X kg/ kg clinkerT 67

oC

Cp 0.2881 Kcal / KgoC


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Q = 19.3 X Kcal/Kgclinker


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Total heat Input

7216 X37.5510.8

1.340.10919.3 X

7235.3 X + 49.799

Total heat output

418.7833.85136.7

38.483.31.8057.29 X10.250.686

743.724 + 7.29 X

Total heat Input =

Total heat

output

7235.3X + 49.799 =743.724 + 7.29X

7228.01 X = 693.925

X = 0.096kg coal /kgclinker

Coal consumption 0.096

kg coal /kg

clinker

Heat consumption 692.7 kcal/kg clinker


75/78

SUMMARY OF HEAT BALANCE

Kiln Feed = 648 Tph

Clinker out = 405 Tph

Kcal/kg

clk. %

Kcal/kg

clk. %

Clinker 38.4 5.2 Cooler air 10.8 1.4

Heat of reaction 418.8 56.3 Kiln feed sensible heat 37.6 5.1

Kiln feed return dust 3.9 0.5 Fine coal sensible heat 1.9 0.2

Moisture evaporation 2.5 0.3 Coal conveying air 0.9 0.1

Cooler exhaust air 83.3 11.2 Primary air sensible heat 0.4 0.1

Preheater flue exhaust gas 136.7 18.4 Cooler water spray 0.1 0.0Cooler water spray

evaporation 10.2 1.4 Coal specific heat 692.7 93.1

Kiln 15.7 2.1

preheater ,tad and cooler 35.0 4.7

Total 744.4 100 Total 744.4 100

* All heat measured in kcal/kg clinker

Net specific heat

consumption(coal)692.7

Kcal/Kg

clinker

Radiation & Convection losses

Heat output Heat input


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OPTIM ISATION IN CEMENT KILN

ROTARY KILN FIRING SYSTEMS

The minimizing excess air in rotary kiln without any formed CO leads toimprovement in the performance of the kiln and consequently leads to reduce the

fuel energy consumption shorten and intensify the flame leads to reduce the fuel

energy consumption. Further in Plant optimized kiln burner primary is also

considered for decreasing fuel energy consumption

Lime saturation factor, sillica moduli and alumina moduli of kiln feed

The fuel consumption can be decreased by reducing lime saturation factor (LSF),

sillica Moduli (SM) and alumina moduli (AM) of kiln feed. These ratios are very

important for producing the optimum quality of cement required.

Fuel quality and fuel combustion efficiency

In Kotputli cement plant largest proportion of energy consumed in manufacturing

of cement consists of fuel that is used to heat the kiln. Therefore, the greatest gain

in reducing input may come from improved fuel efficiency. The fuel energy

consumption can be decreased by selecting the type of fuel which having higher

calorific value and easy to combustion. In Addition to that, by adjusting the flame

shape, the fuel energy consumption in the plant can be improved.


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UTIL I ZATION OF WASTE HEAT

The overall efficiency of the kiln system can be improved by recovering some of

the heat Loss. The recovered heat energy can then be used for several purposes

such as for electricity Generation. Some major heat losses that can be considered

for heat recovery are heat losses by kiln exhaust gas, hot air from cooler stack and

radiation from the kiln surface. The amount of the heat in the waste gases can be

utilized mainly depends upon the flows, Temperature of the waste gas and thermal

capacity of the waste gas. Some methods can be done as below:

Exhaust gas from preheater

In the preheater mainly moisture removal takes place and heat is utilized in thatway but the Temperature of the gases is very high. If the raw materials moisture

content is low, we can only use a part of this gas for drying. In this case a waste

heat boiler can be installed which Utilizes the upper temperature of the exit gas at

around 300 degree Celsius.

Exhaust air from the cooler

In a cooler considerable amount of exhaust air is obtained as waste air. Thetemperature of this waste air lies in the range 200-300 degree Celsius. The exhaust

air can be extracted from the cooler at two different points. In this case, waste air

can be divided into zones inside the cooler, colder and hotter portions. The hottest

portion can be used for heating of the thermal and drying of slag. It can also be

used for steam. A colder portion of air could be used for heating of water to

produce steam to generate power by using turbine.


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