Certificate

This is to certify that the work presented in this project report is a bonafied work of

SUBHAM KUMAR MODI a student of 7th semester B.Tech (mechanical engineering) of

“Academy of Technology” Hooghly, West Bengal has undergone a indutrial training from

01.07.2016 to 30.07.2016 at THE POWER PLANT and THE SINTER PLANT of TATA METALIKS

LIMITED, vill: Mahespur, PO: Samraipur, PS: Kharagpur, Local: Paschim Medinapur, 721301,

WEST BENGAL, INDIA

………………………………….. …………………………………

Mr. A. BANERJEE Mr. D. BANERJEE

(HOD POWER HOUSE) (HOD SINTER PLANT OPERATION)

…………………………………… ……………………………………

Mr. E. A. KUMAR Dr. S. SAHAI

(HOD SINTER PLANT MAINTAINANCE) (HEAD PLANT HR)

Content

I. CERTIFICATE

II. CONTENT

III. ABSTRACT

IV. ACKNOWLEDGEMENT

1) COMPANY PROFILE

2) INTRODUCTION

3) POWER PLANT

A. OVERVIEW

B. THERMODYNAMICAL CONCEPT OF POWER PLANT

C. STEAM AND WATER CYCLE

D. BOILER AND ITS ASSOCIATED COMPONENTS

E. TURBINE AND ITS COMPONENTS

F. CONDENSOR

G. DEAERATOR

H. FANS USED IN POWER PLANT

I. CHIMNEY

J. DM PLANT

4) SINTER PLANT

A. OVERVIEW

B. SINTER AND ITS PROCESS

C. COMMON UNITS OF SINTER PLANT

D. SINTER MACHINE

5) CONCLUSION

6) REFERENCES

Abstract

Refining of iron ore is the most important need of the era, since everywhere various iron products

are used in different forms and structure. Hence the 1st most primary form that we get after

refining the ore is pig iron.

Pig iron is the intermediate product of smelting iron ore. It is

the molten iron from the blast furnace, which is a large and

cylinder-shaped furnace charged with iron ore, coke, and

limestone. Charcoal and anthracite have also been used as

fuel. Pig iron has a very high carbon content, typically 3.5–

4.5%, along with silica and other constituents of dross, which

makes it very brittle and not useful directly as a material

except for limited applications.

The traditional shape of the molds used for pig iron ingots was a branching structure formed

in sand, with many individual ingots at right angles to a central channel or runner,

resembling a litter of piglets being suckled by a sow. When the metal had cooled and

hardened, the smaller ingots (the pigs) were simply broken from the runner (the sow),

hence the name pig iron. As pig iron is intended for remelting, the uneven size of the ingots

and the inclusion of small amounts of sand caused only insignificant problems considering

the ease of casting and handling them.

Sinter plants agglomerate iron ore fines (dust) with other fine materials at high

temperature, to create a product that can be used in a blast furnace. The final product,

a sinter, is a small, irregular nodule of iron mixed with small amounts of other minerals.

Sintering is the process of compacting and forming a solid mass of material by heat and/or pressure without melting it to the point of liquefaction. Sintering happens naturally in mineral deposits or as a manufacturing process used with metals, ceramics, plastics, and other materials. The atoms in the materials diffuse across the boundaries of the particles, fusing the particles together and creating one solid piece.

Acknowledgement

It is to acknowledge that I, a student of mechanical engineering from Academy of

Technology, Hooghly, West Bengal, present this report on the sinter plant and power plant

that runs on blast furnace gas as fuel to support the two blast furnace (MBF I-II) used to

extract the pig iron. This work is based on the industrial training program conducted under

the supervision of various intellectual engineers and officers associated with TATA

METALIKS, during the period of 30 days, i.e 01.07.16 to 30.07.16

With due respect I would like to thank Mr.D.Banerjee, Mr. A.Banerjee, Mr. E.A.Kumar and

all other members associated with the project guidance. A special thanks to Mr. S.Sengupta

and Dr.S.Sahai without whose help the project would have been a abstract.

The practical exposure of the working of a power plant with fuel as blast furnace gas and the

making and use of sinter in the extraction of pig iron has helped us to understand the

academics of mechanical engineering more transparently. I also appreciate TATA group for

establishing such industries and being a pioneer in the growth and development of the

industrial and economic sector of the nation.

Subham kumar modi

Company’s profile

As one of the leading manufacturers of foundry grade pig iron in India, Tata Metaliks Limited

(TML) is committed to deliver excellence. Inspired by the rich Tata heritage, the Company

has grown from strength to strength over the last two decades since its inception in 1990.

A subsidiary of Tata Steel, TML has its manufacturing plant at Kharagpur, West Bengal, India

with an annual production capacity of 345,000 tonnes of pig iron and turnover of Rs. 12.3

billion in 2014-15. With the help of its team of experienced professionals and state-of-the-

art manufacturing facilities, TML produces one of the finest qualities of pig iron in India.

The Company has been fulfilling its vision of "Reaching Tomorrow First" by offering

innovative products to its customers worldwide. In 2012-13, Tata Metaliks introduced its

premium product Tata eFee®, the first branded pig iron that reduces energy consumption in

foundries by 5-15%. Tata Metaliks also manufactures Ductile Iron Pipes through its 100%

subsidiary company, Tata Metaliks DI Pipes Ltd. (TMDIPL). Setting industry benchmarks through quality and service, as a way forward, the Company

has set ambitious targets of manufacturing and

selling higher volumes of pig iron by increasing

the capacity of its plant. As a part of backward

integration, Tata Metaliks has set up a 4,00,000

tpa Sinter Plant to improve its productivity and

cost competitiveness. With latest capacity

expansions and improvement initiatives, the

Company is on a steady growth curve while

focussing on performance excellence.

Introduction

A blast furnace is a smelting furnace in the form of a tower into which a blast of hot

compressed air can be introduced from below. Such furnaces are used chiefly to make iron

from a mixture of iron ore, coke, and limestone. The first blast furnaces appeared in the 14th

Century and produced one ton per day. Blast furnace equipment is in continuous evolution and modern,

giant furnaces produce 13,000 tons per day. Even though equipment is improved and higher production

rates can be achieved, the processes inside the blast furnace remain the same.

Blast furnace gas (BFG) is a by-product of blast furnaces that is generated when the iron ore

is reduced with coke to metallic iron. It has a very low heating value, about 93 BTU/cubic

foot, because it consists of about 60 percent nitrogen and 18-20% carbon dioxide, which are

not flammable.

The total amount of CO and CO2 gases by volume in the BF gas at the furnace top is around

40 % to 45 % of the total gas volume. The CO/CO2 ratio can vary in a blast furnace. Higher

percentage of CO in the gas makes the BF gas more hazardous. Hence for environmental

consequences this gas is used again by the power house to run the turbine and generate

power , used for various operation in the blast furnace and the industry, reducing the

consumption of electricity from the national power grid.

While the purpose of the sinter plant is to process fine grained raw materials into a coarse

grained iron ore sinter, ready to be charged to the blast furnace. Sintering of fine particles

into a porous clinker – sinter – is necessary to improve the permeability of the burden,

making reduction easier. A high quality sinter has high reducing ability, which reduces the

intensity of blast furnace operations and reduces coke demand.

POWER PLANT

CPP (Captive Power Plant)

Overview

At Tata Metaliks Limited, the plant generates most part of the electricity it needs, through

its two power plants i.e. CPP-1 and CPP-1 . Here CPP means Captive Power Plant. There is

one power plant for one of the blast furnaces (and their supporting plants) each, only the

sinter plant runs on grid power.

A Captive Power Plant is a facility that is dedicated to providing a localised source of power

to an energy user. These are typically industrial facilities or large offices. The plants may

operate in grid parallel mode with the ability to export surplus power to the local electricity

distribution network. Alternatively they may have the ability to operate in island mode; i.e.

independently of the local electricity distribution system.

Captive power plants are a form of distributed generation, generating power close to the source of use. Distributed generation facilitates the high fuel efficiency along with minimising losses associated with the transmission of electricity from centralised power plants.

In Tata Metaliks, blast furnace gas is used as a fuel for the captive power plants. It not only reduces the cost of buying electricity from outside but also is environment-friendly as BFG(blast furnace gas) is harmful to the environment and living beings and it is burned as fuel and then emitted in the air rather than emitting it as it is.

A Captive power plant is useful as:-

1) It provides continuous power supply through self generation i.e. the plant is no more dependent on grid power to run it.

2) It makes the plant more environment-friendly as it reduces the pollution significantly

Blast furnace gas here heats the boiler which in turn generates steam and the steam is used to rotate turbines which are connected to alternators which generate 3-phase AC electricity.

FLOW DIAGRAM OF THE POWER PLANT

#2(4 Megawatt)

SD - steam Drum PS - primary superheater

SS - secondary superheater DS - De- Superheater

MSL - main steam line TG - Turbo Generator

CN - Condenser CT - cooling tower

CEP - condensate Extraction pump EJ - Ejector

BFP - Boiler Feed Pump Eco - Economiser’

DMTP - DM Transfer Pump DM - Demineralised

Thermodynamical concept of working

of a power plant

A power plant follows a combination of reheat and regenerative

modification of the Rankine cycle. In this process heat is added

to the saturated water at constant pressure to form saturated

vapour, then it is superheated at constant pressure to a higher

temperature then the steam expands isetropically in an H.P

turbine and does work on its blades as a result the pressure and

temperature of the steam fall. After this a part of the steam is

regenerated to the feed water heater and the rest is reheated

to a higher temperature isobarically. Then again it expands in

the I.P. turbine generating shaft power and simultaneously fall

in pressure and temperature. From the I.P turbine a part of the steam is again regenerated and the

rest is finally expanded in the L.P turbine. After leaving the L.P. turbine the steam is .85 dry and then

it enters the condenser where the steam forms saturated water by constant pressure heat rejection.

After the condenser the saturated water enters the boiler feed pump which pumps the water to a

higher pressure to the boiler drum.

BOILER

A boiler or steam generator is a device used to create steam by applying heat energy to water

Although the definitions are somewhat flexible, it can be said that older steam generators were

commonly termed boilers and worked at low to medium pressure (1–300 psi or 6.895–

2,068.427 kPa) but, at pressures above this, it is more usual to speak of a steam generator

There are two types of boiler namely:

i) Water tube boiler- In the water tube boiler the water is circulated through pipes in the

walls of the boiler and fire is lighted at the middle by spraying pulverized coal.

ii) Fire tube boiler- In the fire tube boiler the fire is run through tubes at the centre of

boiler and the water is circulated around the fire tubes leading to the heat transfer from

the fire to the circulating water.

WATER CYCLE IN POWER GENERATION

OF A POWER PLANT

In the water cycle of a thermal power plant the saturated water of the condenser is extracted from

the condenser using a condensate extraction pump at a stipulated temperature and pressure. The

C.E. pump, pumps this water into the deaerator to relieve the water of all gas molecules, after

preheating it in the L.P heater. The deaeration is done for safe working of the boiler feed pump,

because if air molecules are sucked into the B.F.P then it may lead to its damage or retard its

pumping efficiency. After deaeration of the water it is sucked into the Boiler Feed Pump, the B.F.P.

then pumps this water into the boiler drum through a H.P. heater and then to an economizer where

the water is finally preheated by extracting heat from the outgoing flue gas from the boiler, leading

to its final increase in its enthalpy.

Now in the boiler drum the saturated water is converted to saturated vapour by heat addition at

constant pressure by passing it through the water tubes of the boiler where there is a large increase

in the enthalpy of the fluid and the constant pressure is maintained in the boiler drum due to the

presence of mixture of the water and vapour and it is also fitted with pressure sensitive valves which

extract steam from the boiler as there is an increase in the boiler drum pressure.

STEAM CYCLE IN POWER GENERATION

OF A POWER PLANT

Saturated steam from the boiler drum is superheated at the same pressure to a temperature of

about 540deg Celsius which is the combustion temperature of coal , by passing it through the

superheated tubes of the boiler. Where there is an increase in its enthalpy. Then the steam is

directed to the high pressure turbine

where the steam expands isentropic ally

through the turbine blades making it to

rotate and here the enthalpy of the

steam is converted to mechanical energy

of the turbine shaft, this leads to a drop

in the temperature, pressure, enthalpy

of the steam. Then from the H.P turbine

a part of the steam is regenerated to the

H.P heater and the rest is reheated in

the boiler at constant pressure to a

higher temperature to obtain an increase in its enthalpy. From the reheated the steam is fed to the

Intermediate pressure turbine, where it expands isentropic ally leading to a drop in its enthalpy and

conversion into shaft power. From the I.P. turbine a part of the steam is again regenerated to the

L.P. heater and the rest is again finally expanded in the low pressure turbine for the extraction of the

remaining enthalpy of the steam and partially converting the steam into water with a quality of .85 .

Then the steam enters the condenser where it is converted to saturated water at constant pressure.

The ph of the water circulating in the cycle is constantly monitored as acidic water may damage the

equipments of the plant. Therefore the ph is always kept less than 7. Now if the ph of the water rises

so this water is discarded from the cycle by throwing out the steam. This process is known as blow

down.

ASSOCIATED COMPONENTS OF A

BOILER

Feed Water Pump:

The first step is to get a constant supply of water at high pressure into the boiler. Since the boiler is always at a high pressure. ‘Boiler feed water pump’ pumps the water at high pressure into the boiler from the ‘feed water tank’. The pump is akin to the heart in the human body.

Drum: The drum itself a large cylindrical vessel that functions as the storage and feeding point for water and the collection point for water and steam mixture. This is the largest and most important pressure part in the boiler and weighs in the range 250 Tons for 600 MW power plant.

Water Walls: Boiling takes place in the ‘Water Walls’ which are water filled tubes that form the walls of the furnace. Water Walls get the water from the ‘down comers’ which are large pipes connected to the drum. The down comers and the water wall tubes form the two legs of a water column. As the water heats up in the furnace a part of the water in the water-wall tubes becomes steam. This water steam mixture has a lower density than the water in the down comers. This density difference creates a circulation of water from the drum, through the down comers, water walls and back to the drum. Steam collects at the upper half of the drum. The steam is then sent to the next sections. The temperature in the drum, down comers and water wall is at the saturation temperature.

Economiser: Most of the sensible heat is absorbed in the Economiser. These are a set of coils made from steel tubes located in the tail end of a boiler. The hot gases leaving the boiler furnace heat the water in the coils. The water temperature is slightly less than the saturation temperature. From the economiser the water is fed to the 'drum'.

Super Heater:

Steam from the drum passes to the Super Heater coils placed in the Flue gas path.. The steam temperature increases from the saturation temperature till the maximum required for operation. The superheated steam then finally goes to the turbine. Final Superheater temperatures are in the Range of 540 to 570 °C for large power plants and SuperHeated steam pressures are around 175 bar.

In our power plant there were three components of super heater

1. Primary Super heater -The steam is heated step by step in this power plant . for improving the steam quality.

2. D-super heater- This super heater is used to control the boiler temperature. A tapping from the Economiser is done to the D-super heater for this purpose.whenever required to lower the temperature it sprays water from the economiser to lower its temperature

3. Secondary Super heater- the steam is further heated in secondary superheater and the steam becomes superheated steam after this point.

TURBINE

A turbine is a simple device with few parts that uses flowing fluids (liquids or gases) to produce

electrical energy. Fluid is forced across blades mounted on a shaft, which causes the shaft to turn.

The energy produced from the shaft rotation is collected by a generator which converts the motion

to electrical energy using a magnetic field.. The heat produced from combustion is used to heat

water in boiler. The liquid water is converted to steam upon heating and is exhausted through a pipe

which feeds the steam to the turbine. The pressurized steam flow imparts energy on the blades and

shaft of the turbine causing it to rotate. In this turbine the compounding is done in thirteen stages by

the blades of the turbine . A tapping is done to from the 5th stage of compounding to the dearator

for compensate the loss in the dearator . The rotational mechanical energy is then converted to

electrical energy using an alternator.

OIL COOLER There is an oil cooling circuit for the cooling of the turbine . the oil is used for two purposes

1. For the lubrication of the bearings and the gear boxes

2. For cooling of the turbine- the cooled oil is circulated in the front and rear side of the tubine

bearing, in the main gear box, and the front and rear bearings

The oil is circulated in the following parts of the turbine and then it feed back to the heat exchanger

where oil is cooled with the induced cool water from the cooling tower. The cooled water is then

pass through an oil filter where extra particles are removed and then it is distributed to parts of the

turbine.

Trip Circuit- There is an trip circuit for any emergengy purpose. The circuit closes the supply of the

steam from the main steam line

Condenser

A condenser is a commonly used term for a water-

cooled shell and tube heat exchanger installed on the

exhaust steam from a steam turbine in thermal power

stations. These condensers are heat exchangers which

convert steam from its gaseous to its liquid state at a

pressure below atmospheric pressure, Where cooling water

is in short supply, an air-cooled condenser is often used. An

air-cooled condenser is however, significantly more

expensive and cannot achieve as low a steam turbine

exhaust pressure (and temperature) as a water-cooled surface condenser.

Condenser- If the steam coming out from the turbine is released into the atmosphere, it will result in a huge amount of wastage of water. So the steam is condensed to water to feed it to the boiler again. Here the there are two subparts:

1) Cooling Tower: Here the steam is cooled by the means of cooling water 2) CWP: CWP or the condensed water pump is used to pump the condensed

water back to the condenser from the cooling tower.

Mechanical draught cooling tower: these uses a power driven fan motors to force or draw air

through the towers. A mechanical induced draft tower with a fan at the discharge (at the top) which

pulls the air up through tower. The fan induces hot moist air out the discharge. This produces low

entering and high exiting air velocities, reducing the possibility of recirculation in which discharged

air flows back into the air intake.

This process continues as long as the condensed water is not at a particular temperature. The condenser contains a hot-well where the hot water is stored.

CEP- CEP(Condensate extraction pump) is a pump used to circulate condensate water in the feed cycle path up to dearator a specified pressure. It is a multi-stage (8-stage) pump.

deaerator

A deaerator is a device that is widely used for the removal of oxygen and other

dissolved gases from the feed water to steam-generating boilers. In particular,

dissolved oxygen in boiler feed waters will cause serious corrosion damage in steam systems

by attaching to the walls of metal piping and other metallic equipment and

forming oxides (rust). Dissolved carbon dioxide combines with water to form carbonic

acid that causes further corrosion. Most deaerators are designed to remove oxygen down to

levels of 7 ppb by weight (0.005 cm³/L) or less as well as essentially eliminating carbon

dioxide.

There are two basic types of deaerators, the tray-type and the spray-type:

The tray-type (also called the cascade-type) includes a vertical domed deaeration

section mounted on top of a horizontal cylindrical vessel which serves as the deaerated

boiler feedwater storage tank.

The spray-type consists only of a horizontal (or vertical) cylindrical vessel which serves

as both the deaeration section and the boiler feedwater storage tank.

FANS FOR POWER PLANT

Supply air for combustion in the furnace and for evacuation of the flue gases formed from

the combustion.

Maintain balanced draft inside the furnace.

Supply air for cooling of equipments working in hot zones.

Supply air for sealing of gates, feeders & mill bearings ets.

Air used for combustion is divided into two parts.

1. Primary air:

Portion f total air sent through mill to the furnace. This air dries the pulverised coal and

transport it to the furnace for combustion.

2. Secondary air

Large portion of total air sent to furnace to supply necessary oxygen for the combustion.

Types of fan

I. Axial fan with two sub groups i. Impulse ii. Reaction

II. Radial fan or centrifugal fan (single suction or double suction).

Forced Draft (FD) Fan:

Supplies secondary air to the furnace through APF to assist in combustion.

Supply total air flow to the furnace except where an independent atmospheric P.A Fan is

used.

Provides air for sealing requirement and excess air requirement in the furnace

Axial fan-reaction type with blade pitch control is use in the pulverised fired boiler.

Induced Draft (ID) Fan:

Suck the gases out of the furnace and throw them into the stack by creating sufficient

negative pressure in the furnace (5-10mmwc) in the balanced draft units.

Located in between the ESP and chimney in the flue gas path.

Radial fans- double suction backward curved vane with inlet guide vane control and VFD is

use in all boilers.

Handles large volume of hot dust/ash laden flue gases from the furnace and all leakage

occurring in the system till the inlet of the fan.

CHIMNEY

The function of the chimney is to eject flue gas out of the plant. The height of the chimney is kept

sufficiently large so that the flue gas does not fall over the plant and also to create a higher draught

for driving the waste out of the flue gas circuit.

.

Demineralised Plant

Typical flow diagram of a DM plant

What is DM Plant? Why use DM plant?

In power plant water is known as the heart of the plant, so it is most necessary to supply salt free

water for process. The demineralization is the process of removing mineral salts from water by

using ion exchange process. The D.M water reduces the scale formation, Deposition and corrosion

of tubes. It increases the life of pipes and tubes in plant. It prevents the deposition of minerals in

turbine blades. It removes Mineral salts in the form of cations such as sodium, calcium, iron, copper

and anions such as chloride, sulphate , nitrate etc.

SOURCES OF WATER

There are 3 types of sources of water-

1. Surface water - River water,lake water, pond water ect.

2. Ground water - Bore water, well water.

3. Sea water - Sea water.

Rain water is the purist of all sources of water. since the water having unique property of absorbing

everything on the earth that is why water is called universal solution. As the rain water falls on the

earth it will be exposed with several gases present in the atmosphere, after falling on the earth

water will be flows through several salts& minerals on the earth. In this way water is getting

contaminated.

Reservoir:-Reservoir is used for water storage purpose. Water is taken from here for dm

water process work

MULTI GRADE FILTER (MGF):- It consists of vertical or horizontal pressure filters that

contain multiple layer of coarse fine sand.It reduce turbudity and TSS (<5 PPM) from water. water is

passed through multi layers of filter media consisting graded sand, pebbles and gravels layers. The

contaminants in the water are captured in the media bed and filtered water passes into the

discharge manifold at the bottom of the tanks. The next and last step is back washing, a process of

effectively removal of captured contaminants from the media bed. After back-washing the filter is

rinsed with raw water and after the required quality of water is achieved the filter is put back into

service.

Activated carbon filter- It reduces the turbidity, filters totalled dissolved solids, reduces

the smell of water and for dechorinization purpose

Strong Acid cation(H+

)- as the name suggest it absorbs the cation from the the water.

There is a resin which can catch the cations. The H+ are then regenerated by Hydrazine.

Re-H + KCl = Re-K + HCl

Strong Base anion(OH-

)- It absorbs the anions from the water. The resin absorbs the

excess anions from water

Mixed bed- mixed bed contains both H+ and OH- bed resins. If some cations or anions are not

removed it is then removed by mixed bed

Degreaser system- in this system the co2 and other gases are removed

Sinter plant

overview

Sintering plants are normally associated with the production of hot metal in blast furnaces in integrated steel pants. The process of sintering is basically a pre-treatment process step during iron making to produce charge material called sinter for the blast furnace from iron ore fines and also from metallurgical wastes (collected dusts, sludge and mill scale etc.). The sintering technology was originally developed for the purpose of using the iron the metallurgical waste of a steel plant and iron ore fines in the blast furnace. But currently the focus has changed. Now the sintering process aims to produce a high quality burden for the blast furnace. Today sinter is the main metallic burden for a large blast furnace. The Principle of sintering The principle of sintering involves the heating of iron ore fines along with flux and coke fines or coal to produce a semi-molten mass that solidifies into porous pieces of sinter with the size and strength characteristics necessary for feeding into the blast furnace. It is basically an agglomeration process achieved through combustion .

Sintering Plant - TATA METALIKS LTD.

Sinter Project approved by TML Board 31st January 2011 by CAPEX.

40.5 SQM size Linear Sinter Machine and Linear Cooler.

Consortium Partners : China metallurgical Engineering and Project Corporation (MEPC).

SINO India Metallurgical Engineering and Supply (P) LTD.

Karan Construction Company (KCC)

Site Work Started on 4th march 2011.

The Product Sinter

The product of the sintering process is called sinter and is having good following quality characteristics

1. Chemical analysis 2. Grain size distribution 3. Reducibility 4. Sinter strength

Typical properties of sinter

Item Unit Value

Fe % 56.5 to 57.5

Feo % 6.0-8.0

SiO2 % 4.0 to 5.0

Al2O3 % 1.8 to 2.5

CaO % 7.5 to 8.5

MgO % 1.6 to 2.0

Basicity (CaO/SiO2)

1.7 to 2.9

ISO Strength (+6.3mm) % >75

RDI (-3 mm) % 27-31

The Process

The process of sintering begins with the preparation of the raw materials consisting of iron ore fines, fluxes, in-plant metallurgical waste materials, fuel and return fines of the sinter plant. These materials are mixed in a rotating drum and water is added in order to reach proper agglomeration of the raw materials mix. This agglomeration is in the form of micro-pellets. These micro pallets assist in obtaining optimum permeability during the sintering process. These micro pellets are then conveyed to the sintering machine and charged. A layer of controlled size sinter (bedding) is fed to the bottom of the sinter machine grates for the protection of the grates. After this the moistened micro pellets of the raw materials mix is fed and leveled.

After the material is leveled on the sinter machine, the surface of the charged material on the sinter machine is ignited using gas or oil burners. Air is drawn through the moving bed causing the fuel to burn. Sinter machine velocity and gas flow are controlled to ensure that “burn through” (i.e. the point at which the burning fuel layer reaches the base of the strand) occurs just prior to the sinter being discharged. During the machine movement the sintering of the material bed on the grate proceeds downward. Waste gas circuit is to be fully leak proof, not allowing air from atmosphere to be sucked by the system. This results into saving of power in the waste gas circuit.

At the end of the machine the sintered material in the form of cake is discharged into the hot sinter crusher. Here the hot sinter cake is crushed to a pre-determined maximum particle size. From here the sinter is discharged onto sinter cooler which can be either straight line or circular cooler. After cooler the sinter is transferred to the screening section. In the screening section the product sinter, bedding and return fines are separated. Return fines, not suitable for downstream processing, are conveyed to a bin for recycling in the sintering process.

Common units of a sinter plant

1. Raw materials handling system

2. Crushing of fluxes and coke breeze

3. Propositioning of raw materials

4. Mixing and nodulizing

5. Charging of mix on to sintering bed

6. Ignition of charge on sinter bed

7. Sintering process along the sinter bed

8. Cooling of product sinter

9. Screening of cold sinter

10. Conveying of product sinter to BF stock house

raw materials handling systems

A belt conveyer is an iron structure to support the belt used for transporting material

generally at a very small or zero angles to the horizontal from one location to another. The

belt is supported by idlers throughout the way. The idlers are arranged in a trough on the

carrying side and flat on the bottom or return side. The driving unit move one or more

pulleys which, in turn move the belt. The whole conveyor is supported on a steel structure

known as TRANSOM, which supports and keeps the idlers in line as well as supports the

pulleys and the drive cover.

The gravity pulley is tightening the

entire belt so that there should not

be any sagging of belt in the

conveyor system of RMHS (Raw

material handling system).

Belt conveyers are used to carry

economically greater diversity of

bulk materials and for greater

distances. It can be use for material

varying in lump size, moisture

content, chemical composition and

characteristics.

Crushing house

The required material is needed of 3mm size, and

the given material supply is of variable sizes so, the

given materials should be properly crushed to the

required sizes. Each material need a different

crusher, like coke breeze needs a 4 roll crusher and

fluxes like dolomite and limestone needs hammer

mill for crushing, it’s their force withstanding quality.

In the plant there are 2 hammer roll crusher(both forward and reverse motions are

possible)and one four roll crusher

From the hoppers, the raw materials like coke breeze, dolomite and limestone travel

through conveyor belt as a medium. Coke breeze & flux (i.e. fuel and flux) belt and then

separate into F1, F2, F3 and F4 line for fuel and FL1, FL2, FL3, FL4 and FL5 for flux. The fuel

circuit goes to 4 roll crusher and the flux circuit goes to hammer mill.

FOUR ROLLER CRUSHER

Four roll crusher is used to crush coke. The product

coke breeze are then transferred to the bunkers via

conveyer belts the crossectional diagram

Specification of four roll crusher

Maker Henen qurying machine manufacturing

Model 4 P G 900*700

Feeding size 40/100

Discharge size Less than 10

Motor power 24/30

Crushing capacity Less than 18 TPH

SRL number 11105003

Roller diameter 900mm

Roller length 700mm

Upper roller gap 8-10mm

Lower roller gap 3-4mm

HAMMER ROLL CRUSHER

Hammer roll crusher is used to crush to

crush fluxes like dolomite and limestone. There

are two hammer roll crusher one for back up

purpose. The fluxes like dolomite and limestones

are crushed one by one and the size is 3mm

+80% and he send to the bunkers after screening

The specification of hammer roll crusher is

below:

Hammer crushing mill

Feeding size 40mm

Product size 3mm

Rotor speed 1104 rpm

Capacity 35 TPH

Propositioning of raw materials

This is the sector where the raw materials after crushed gets into a line, feed one above the

other. In raw feeder particles plant, there are a total of 14 hoppers,

1- 6 hoppers are for iron ore fines,7 - 8 hopper are for crushed coke breeze and the

9th,10th,11th & 13th are for the fluxes crushed dolomite, limestone alternatively. The 13th

hopper is for quick lime, which is also a kind of flux. These raw materials are layered one by

one using feeder machine. There is a separate machine used for weighing and feeding into

the conveyor belt, that machine is called weigh feeder. This weigh feeder is used to

estimate the output product in terms of tons per hour (TPH).

weigh feeder

This machine, weighs the input raw material and the output material is compressed to the required

quantity and estimated to tons per hour (TPH). This machine is connected to the main control frame

for estimating quantity of output. The techniques used are zeroing and tearing. Zeroing is making

the overall weight of the quantity of the material to zero and tearing is distributing the weight all

throughout.

Mixing and nodulizing drum

The raw materials which are feed from raw feeder

particles chamber and sent to mixing and nodulizing

drum. In this drum, the raw materials are mixed like

churning and a little moisture is added and mixed

throughout and the product is sent out through the

product belt. This mixing an nodulizing should have

proper moisture else the mixture will be damp. So,

there is a moisture detecting machine known as

“moisture probe “This detects the moisture content in

the mixture and alert the unit if the content of

moisture is either high or low.

Mixing and nodulizing

Drum diameter 2800mm

Drum length 9000mm

Inclination 0.9o

Speed 6 RPM

Capacity 150 TPH

Sinter machine

The sinter machine consists of following components

1. Charging of the raw materials

2. Charging of Hearth layer

3. Water jacket

4. Ignition chamber

5. Wind chamber for suction

6. Pallets

7. SRC (single roll crusher)

Specification of sinter machine

Surface area 40.5m2

Effective length 27.0m2

Machine width 1.5 m

Bed height 700mm

Machine speed 0.5 to 2.4 m/min

Charging of raw material

The mixed produced after mixing in MND is placed in the bed of the sinter machine i.e the hearth

layer. The top layer is sprinkled with coke bridge for better ignition.

Drum feeder

drum feeder is used to uniformly distribution of the mix(from MND) to the hearth layer

Charging of the Hearth layer

The product of sinter machine i.e. sinter is been screened just like flux screening. And we know that

our objective from starting was to make a product of less than 5mm. so when the product of sinter

machine i.e. sinter is made, the product is screened well and the product which are above 5mm are

used as hearth layer in the sinter machine. This sinter is needed to be reduced to lower size so this is

sent back to the sinter machine. This is made to be hearth layer because; it’s porous and protects

the suction pipe from getting choked by raw materials.

Water jacket

The water jacket is placed just in front of the ignition chamber so that the heat shouldn’t radiate

from ignition chamber to the other places. This jacket is hollow and is continuously circulated by cold

water.

Ignition chamber

This name indicates ignition i.e. starting of fire or heat. In this chamber the input raw materials and

hearth layer is been heated to the temperature 900-1100oC.This ignition chamber is ignited using

BFG gas. This BFG gas is used as a fuel to start the heat. And this process is continued for a serial

sequence of time. Each pallet gets heat approximately a time of 2-3 minutes. And this upper layer of

the raw materials gets pretty much heated up.

Wind chamber(for suction)

Suction valves are the compressors used to pull the air out of the raw materials layers. The pressure

produced by the suction valve is -1Kg per cm2. That is a huge amount of pressure and “-“ the

negative sign shows the direction of force. This suction takes place just like the smoking of cigarette,

at first the upper layer of the cigarette is burnt, and then slowly when u inhale the flame spreads to

the consecutive layers and at last to the end. Just like that when the upper layer is burnt and the

suction valve applies a negative pressure i.e. the air is sucked in, the heat and temperature spreads

from one layer to another till the bottom layer. This is how it works. And this is the use of suction

valve.

Pallets

Pallets are the covering medium for the raw material or the product. It acts as a box to hold the raw

materials going through this process. This pallets contains a material to protect the raw materials by

giving base, it’s known as Grate bars. These pallets are of various numbers. Each pallet contains raw

materials which later get converted to sinter cake. It just acts as a medium of transport.

Single roller crusher

The sinter cake after coming through pallet cart falls into the single rotor crusher (SRC). In SRC the

sinter cake is further crushed in the required size and then sent through the sinter cooler by the

conveyor belts to the screening house

Single roll crusher

Model size 1500*1720 mm

Capacity 80-160 TPH

Speed of the crusher 6.6 RPM

Total no. of hammers 21(7*3)

Sinter cooler

The hot sinter after crushing in the SRC is

passed through sinter cooler for cooling.

In the sinter cooler the sinter is cooled by

blowing air through it. There are 4

FD(fored draft ) fans for this purpose.

The specipication of sinter cooler

Linear cooler

Effective area of cooling surface 45.6 m2

Trolley running speed 0.6-0.95 m/min

Maximum processing capacity 110 TPH

Effective cooling time 40-70 min

Bed height 1200mm

Cooler inclination 9o

Feeding temperature < 750oC

Discharge temperature < 120oC

Material feeding size 6-200mm

Bulk density 1.7 T/m3

Sinter Screening

Sinter screen is used to separate the product of required size from the outcome size. The sinter

which are less than 5mm are given as a by product and the sinter above 5-10mm goes for hearth

layer and above 10mm sinter goes to Blast furnace for reduction process. This sinter screen works in

elliptical motion rather than in linear motion.

ELECTRSTATIC PRECIPITATOR

An Electrostatic Precipitator (ESP) is a filtration device that removes fine particles, like dust and

smoke, from the flowing gas using the force of an induced electrostatic charge minimally impending

the flow of gases through the unit.

The most basic precipitator contains a row of thin vertical wires, and followed by a stack of large flat

metal plates oriented vertically, with the plates typically spaced about 1 cm to 18 cm apart,

depending on the application. The air or gas stream flows horizontally through the spaces between

the wires, and then passes through the stack of plates.

A negative voltage of several thousand volts is applied between wire and plate. If the applied voltage

is high enough, an electric corona discharge ionizes the gas around the electrodes. Negative ions

flow to the plates and charge the gas-flow particles.

The ionized particles, following the negative electric field created by the power supply, move to the

grounded plates. Particles build up on the collection plates and form a layer. The layer does not

collapse, thanks to electrostatic pressure (due to layer resistivity, electric field, and current flowing

in the collected layer).

The collected particles on the collecting plate is removed by methods such as

Dislodging by raping the collecting particles.

Scraping off with a brush.

Washing off with water.

and then removing from a hopper.

HOPPERS:

These are bins used to collect and temporarily store the particles removed during rapping. They are

located at the bottom of an ESP. A Hopper is a large, pyramidal shaped container used to hold

particulate matter that has been collected from expelled air. Hoppers are installed in groups to allow

a greater collection quantity.

ID FAN

Under the effect of main system fan ,the dust containing gas enters the dust precollection chamber

through inlet and the duct-containing air flow knocking against finder turns to hopper. At the same

speed the flow speed slow down. Parts of heavier particle slow down Induced Draft (ID) fans are

used to create a vacuum or negative air pressure in a system or stack.

Fans that are used to evacuate a space or create negative air pressure in a system are referred to as

induced draft fans. Occasionally, manufacturing spaces are required by specifications to be

maintained at a specific negative pressure. Induced draft is also used to identify the combustion

process used in large boilers. When mechanical ventilation is supplied to these boilers, the heat

transfer rat e increases; the boiler can be reduced in size to produce the same amount of energy as

natural draft. The induced draft fans used in combustion systems are normally high temperature and

extra heavy-duty construction. Induced-draft An induced-draft burner uses a blower to pull air into

the burner, and through the combustion chamber and heat exchanger. The fan then pushes the flue

gases out through the vent. This creates negative pressure in the furnace, and may create positive or

negative pressure in the venting systems. Sidewall-vented, induced-draft furnaces have significant

positive pressure pushing exhaust gases outside. Induced-draft furnaces designed to vent into

chimneys or B-vents, for example, are baffled so the exhaust gases are at atmospheric pressure

(considered negative) when they enter the chimney. These can then be manifold with natural-draft

water heaters, for example. Sidewall-vented systems cannot. Induced-draft fans are also called aunt

blowers, power vents or power venters . Systems with induced or forced draft fans are sometimes

referred to fan-assisted.

CONCLUSION

A month training at TATA METALIKS LTD. has been a enriching experience for me . it has not only

helped me in venturing into the practical aspects, but also had allowed me to broaden our vision and

helped us to co relate our academics with the real work, processes and its application. But still there

is a lot to know and discover. With the passing time and technologies more and more technologies

are developed to generate energy conventionally and efficiently, hence increasing the production

without any wastage of resources.

At the end I Subham kumar modi would take the opportunity to thank the TATA GROUP and its

associates & engineers, under whom i have enriched my knowledge.

Dr. Sikha Sahai

HR PLANT HEAD

Reference

http://ispatguru.com/blast-furnace-gas-its-characteristics-and-safety-requirements/

http://ietd.iipnetwork.org/content/sinter-plant

google.co.in/?gfe_rd=cr&ei=D7XNVuHnEcSL8QeU0rmoDg&gws_rd=ssl

https://en.wikipedia.org/wiki/Power_station

https://en.wikipedia.org/wiki/Sintering

http://www.tatametaliks.com/corporate/company-profile.aspx