submitted report
TRANSCRIPT
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A.Company ProfileName of the company : Jaypee Rewa Plant (JRP)
Jaiprakash Associates Limited
Cement Division.
Establishment Year : 1986
Chairman : Mr. Manoj Gaur
No of Employees : 3330
Products
Production Capacity : 3.3 MTPA
Motto : Work for Quality, Safety,Health
& Environment
Product Range (Cement)
Type - Grade Brand Name
OPC-53 SUPER PLUS
OPC-43 TIGER
OPC-33 BUNIYAD
OPC - IRS T-
40/53S
BULAND
PPC BUNIYAD
PPC BULAND
PPC
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B.Brief HistoryYear 1979:
Jaiprakash Associates Private Ltd. (JAPL) formed. Ultra Rasayan Udyog Ltd. was formed for setting up
Malathion Technical plant in Sikandrabad (U.P.),
which was changed to Jaiprakash Enterprises Ltd.
Year1980:
Hotel Siddharth was set up.Year1982:
Hotel Vasant Continental was set up.Year1986:
Commissioning of 1st unit of 1 MTPA Jaypee RewaPlant.
Formation of Jaiprakash Industries Ltd. (JIL) byamalgamating JAPL into Jaypee Rewa Cement Plant.
Year1991:
Commissioning of 2nd unit of 1.5 MTPA Jaypee RewaPlant (JRP) in District Rewa (M.P).
Year1992:
Formation of JaiprakashHydro Power Ltd (JHPL).
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Year1995:
Formation Jaiprakash Power Ventures Ltd (JPVL). Hotel Jaypee Residency Manor set up.
Year1996:
Commissioning of 1.7 MTPA Jaypee Bela Plant (JBP) inDistrict Rewa, M.P.
Year1999:
Jaypee Palace Hotel, Agra set up.Year2000:
Acquisition of land for Jaypee Greens Ltd.Year 2001:
Commissioning of .6 MTPA Jaypee Blending Units atAllahabad district in U.P. The first of its kind in the
country.
Jaypee Institute of Information Technology (DeemedUniversity Since November 1, 2004) at Noida, U.P.
Year2002:
Commissioning of 1.0 MTPA grinding unit in districtAmbedkar Nagar in U.P.
Jaypee University of Information Technology (StateUniversity), Waknaghat was set up.
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Year2003:
Commissioning of 25 MW captive Thermal PowerPlant-1 at JRP.
Formation of Jaiprakash Associates Ltd (JAL) formedby merging JIL with Jaypee cement Ltd.
Year2004:
Commissioning of 25MW captive Thermal PowerPlant-2 at JRP.
Commencement of Work for setting up 3MnTPACement Plant at Baga & Baghri at District Solan in H.P.
and 1.5 MTPA.
Year2005:
Successful completion of up-gradation scheme,enhancing the total capacity of Rewa Operation to
7.0 MTPA.
Shares of JHPL Listed on BSE/NSE. First hydro powercompany to be listed in the country.
Year2006:
Setting up of Madhya Pradesh Jaypee MineralsCorporation Ltd. (MPJMCL).
Commissioning of 38.5MW captive Thermal PowerPlant-3 at Jaypee Rewa plant.
Railway siding operational at Jaypee Bela plant.
Commencement of work for setting up a new greenfield 1.5 MTPA cement plant in district Sidhi, M.P.
Acquisition of cement plants & assets of U.P. StateCement Corporation Limited (in Liquidation) of 2.5
MTPA capacity.
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Acquisition of Gujarat Anjana Cement Limited forsetting up a Green field cement plant of 1.2 MTPA
capacities Bhuj district in Kutch, Gujarat.
Year2007:
Signing of MOU with Gujarat Mineral DevelopmentCorporation (GMDC) for setting up a new Green Field
Cement Plant of 1.2 MTPA capacity, in JV in Kutch
district, Gujarat.
Signing of MOU with Government of H.P, or setting upa new Green Field Cement Plant of 2.0 MTPA capacity
at Chamba district in H.P.
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C.IntroductionJaypee Rewa cement is sub division of
Jaiprakash Associates Ltd. Jaiprakash
Associates is one of the biggest construction
companies in India. Mr. Manoj Gaur is the
Executive chairman of this company with its
head office is in New Delhi.
Jaypee Rewa cement is single largest
production unit. Its annual production is
about 3.3 Million Tons. There are two units installed for the production of
clinker namely Unit-1 &Unit-2.
Unit-1: Supplied by Krupp. Plysious (Germany). 1.5 million ton capacity was
commission in December 1986.
Unit-2: Supplied by F. L. Smidth (Denmark) 1.8 million ton capacity was
commission in April 1991.
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D.Cement ManufacturingProcess
I. MiningThe cement manufacturing process
starts from the mining of limestone,which is the main raw material for
making cement. Limestone is excavated
from the quarries at about 6 m from
ground level after drilling and blasting
and than loaded on to the dumpers
which transport the material and
unload it into the hoppers of limestone crusher.
II. Crushing Stacking & Reclaiming ofLimestone:
The limestone crusher crushes the limestone to
approximately 70 to 80mm size and discharge
the material onto a Belt Conveyer which takes itto the Stacker via the Bulk Material Analyzer.
The material is stacked in longitudinal
stockpiles and than Limestone is extracted
transversely from the stockpiles by the
Reclaimers and conveyed to the Raw Mill
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hoppers for grinding of raw meal.
III. Crushing Stacking & Reclaiming ofCoal:
The process of making cement
clinker requires heat. Coal is used as
the fuel for providing heat. Raw coal
is stored in the coal yard. Raw coal is
dropped on a belt conveyer from a
hopper and is taken to a crusher for
being crushed. Crushed coal
discharged is stored in the longitudinal stockpiles from where it is
reclaimed by the Reclaimer and taken to the coal mill hopper for grinding it
to fine coal.
IV. Raw Meal Drying/Grinding &Homogenization:
Reclaimed limestone along with some laterite
stored in their respective hoppers is fed to the
Raw Mill for fine grinding. The hot gases coming
from the Cooler House are used in Raw Mill fordrying. Grounded Raw Meal is than transported
to the Electrostatic Precipitator (ESP) /Bag
house, where it is collected and then stored and homogenized in the
concrete SILO. Raw meal extracted from the SILO is than fed to the top of
the pre-heater for pyro-processing.
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V. ClinkerizationCement clinker is made by
pyro-processing of Kiln feed
in the pre-heater and the
rotary Kiln. Fine coal and air
is used as fuel to heat the
Kiln and the pre-calciner
located at the bottom of the
5/6 stage pre-heater. Hot clinker discharged from the Kiln drops on the
gate cooler and gets cooled. The clinker discharged by the Cooler House
falls onto the pan conveyor and it is than transported to the clinker
stockpiles/SILO. The clinker is than taken from the stockpiles/SILO to the
Ball Mill Hoppers for cement grinding.
VI. Cement Grinding & StorageClinker and Gypsum (for OPC) and also Pozzolana (for PPC) are extracted
from their respected hoppers and fed to the cement mill. These ball mills
ground the fed materials to a fine powder. The mill discharge is than fed to
the elevator, which takes the material to the separator, which separates
fine product and the coarse material. The latter is sent to the mill inlet
again for regrinding and the fine product is stored in concrete SILO.
VII. PackingCement extracted from SILO is than conveyed to the automatic electronic
packers where it is packed in 50 Kg polythene bags and dispatched in
trucks.
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SHUTDOWN OPERATIONS
INKILN AND COOLER HOUSE
(UNIT-2)
I. Detailed Descriptiona. Rotary Kiln
Kiln is cylindrical rotary equipment rotating on supporting rollers at about
3.5 RPM and discharges on the completion of calcinations reactions. Firingis done from Kiln outlet with the help of burner pipe.
i. Technical specification of Rotary Kiln:Unit-2
Maker FLS
Pre-calciner SLC
Diameter 4.75 M
Length 75 MCapacity 5500 TPH
Rpm 3.8
Burner pipe Duoflex
Slope 8
Fuel Used Coal
Thrust roller Hydraulic
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Thermal Load 14.44
Supporting Roller 6nos
ii. Construction:a. Kiln inlet (consist seal, grease pump, lines, cylinders etc)b. Girth gear (Gear, pinion, spray system)c. Thrust roller (Hydraulic cylinder, oil line)d. Supporting roller & tyre (Consist of bearing, chair plate, bolts etc)e. Kiln outlet seal (S.S shims, crown shell, seal)f. Burner pipe(consist of air pipe, coal pipe, diesel pipe etc)
Kiln inlet
Kiln inlet is sealed by sealing arrangement. Greasing is done by
pneumatic pump seal. It consists of 10 to 14 segments so that it can be
mounted and disassembled from Kiln inside. A conical section forms an
extension of the inlet ring. A brick retaining ring has been mounted at
the end of conical section.
Girth Gear
Kiln is rotating by Gear pinion arrangement.
Girth gear is mounted on Kiln with the help of
spring plates.
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Specifications of Girth Gear are as follows:
KILN GIRTH GEAR
P.C.D. 7149 mm
No. of Teeth 220
Width of Teeth 640 mm
Thrust Roller
The function of thrust roller is to control
axial moment of Kiln in both upward &
downward directions.
Supporting Rollers & Tyre
Supporting rollers are for support of Kiln. They are in contact with tyre
which is fitted in Kiln shell.
Kiln Outlet
There is a sealing arrangement at Kiln outlet.
Burner Pipe
It is for firing of fine coal into the
Kiln. Air is controlled by damper
and fine coal by solid flow meter.
Duoflex type of burner is used inKiln Unit-2
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iii. MaintenanceRefractory Lining
The high temperature inside the Kiln leads to severe
thermal shocks which cause cracks in the brick lining as
well as Castable. Also, during the half yearly maintenance as
the Kiln is stopped, leads to high temperature changes
which causes cracks in the brick lining. This may cause the
molten liquid to reach the Kiln shell causing damage to it.
Hence the Kiln stoppages are usually averted as much as
possible. It may be noted that temperature of shell does not
rise beyond 300 C
The Castable is used wherever brick lining cannot be used
in Kiln generally in sections which are not straight.
Process of Replacing Brick Lining
Check the refractorybrick lining during the
maintenance time.
If the brick lining iscracked than we replace
the lining.
The cost of brick lining isquite high so we use
bricks according to the
temperature they are
supposed to sustain. Usually high alumina percentage bricks
are placed near the Kiln Inlet where the temperature is
highest and material flows in molten form.
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During lining of bricks a ceramic plate is placed in betweenthe two refractory bricks using adhesive. This is provided to
avoid stresses in the brick during thermal expansion.
A Ram is placed inside the Kiln which presses and supportsthe brick lining.
The last brick to be placed is known as Key Brick which isplaced with 2 shims maximum in order to tighten the whole
ring.
When the entire lining is completed, the pneumaticallydriven brick lining machine is used in order to press the
lining for final fit.
The bricks which were used were DALMIA 625 and 425where first letter denotes the diameter and last two the
thickness of insulation.
For e.g.: 625 means the brick is for lining 6 m diameter Kilnand insulation thickness is 250 mm. Since the diameter of
the Kiln is 4.75 m so these bricks are placed in the ratio of
1:1.
Castable is placed over the tip casting plate by weldingsmall sections
over the tip
casting plates and
than filling
Castable in it.
After the Castable
has solidified we
cut the extruding
parts. And remove
the support plates.
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Tip Casting Plate
The Tip Casting plate is placed
at the tip of the Kiln outlet.
These plates are those overwhich a ring of Castable lining
is made. These plates protect
the Kiln shell from the hot
molten material when the
Castable lining has worn off due to the continuous abrasive
action of between molten material and tip.
Process
Tip Casting Plate is imported from outside and is placed just
on the tip of the Kiln and screwed to the tip. Later this forms
a base for the Castable.
Chair Plate, Shims and Guide Blocks
The live ring migration is
equal to the relative motion
between Kiln Shell and Tyre
during a single revolution. It
is an indicator of ovality of
Kiln Shell. Chair plates are
inserted between the Kiln
Shell and Tyre and Shims areinserted in between to
reduce the clearance. This
stops the mitigation. It should be seen that mitigation of
Tyre does not exceed beyond 20 mm as it would reduce
Kiln lining life.
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Guide blocks are also provided to keep the live ring in its
axial position on the Kiln shell. This implies the transfer of
axial thrust on the Kiln shell between live ring and side
guides. The relative moment of the face depends upon the
ovality of Kiln shell. Therefore, there is a chance of high
wear.
The maximum clearance between the guide blocks and the
tyre should not exceed 4 mm.
At the time I was at the Plant a design change of guide block
was taking place. Previously adjustable guide blocks used to
be bolted over the Chair Plates. But over a period of time the
nuts used to get jammed and were no longer adjustable
hence the newer version of guide blocks were directly
bolted over the Chair Plates.
Crown Shell and Sealing Plate
Due to high
temperature andoxidation due to
atmosphere
surrounding it the
crown shell and sealing
plate may wear off and
get damaged. So during
shut down these
damaged plates need to
be checked and should be replaced if damage to them is
more than a limit.
The function of Crown shell is that it acts a nozzle for the air
blowing from side cooling the lip of the Kiln.
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Also Sealing plate does not allow the hot gases from the Kiln
to escape thus trapping energy.
Rollers
Rollers are also
checked because
they sustain heavy
loads hence even a
small particle will
lead to great loss
and wear the
surface. These
rollers are not
replaced rather grinded so as to make them polished and
workable.
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b.Cooler HouseIt is a vital part of Kiln System and a decisive influence on plant performance.
It is for the cooling of clinker (less than 100 degree), as produced in Kiln.
i. Technical Specification of Grate cooler
ii. Main Functions of Cooler HouseClinker cooler has two main functions to perform. These are as follows:
1. To cool the hot clinker quickly (from 1400to normally 100-200 degrees).2. To provide necessary hot air byrecuperating as much heat as possible from
hot clinker by heating up air use for
combustion of coal in pre-calciner and Kiln.
After introduction of red hot clinker into
the cooler, it falls over IKN plates. These
are fixed grate plates and hence to move
the clinker an air blaster is placed at the
start of the Cooler House. After this the
clinker moves to mechanically driven
gates. These grates are such that one row of grates is fixed and one row of
Type Folax
Make FLS(Germany)
Capacity 5500 TPD
Size 37.8m length*5.1m width
No. of gates 4
No. of cooling Air fan 11
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grates is reciprocating with the help of motor. These reciprocating grates
ate installed over a beam which moves over the rollers. The grates are
having holes from which pressurized air flows and cools the clinker
quickly.
Clinker cools down gradually as it moves, due to the air blown by the
centrifugal air pumps which is taken from the atmosphere. Air flowing
from below through the cooling grate plates helps in cooling the clinker
quickly
Clinker escaping out of the cooler is fed to a hammer crusher, since lumpy
material requires crushing. Crushed material is transported to clinker silo
through deep bucket conveyor. Temperature of clinker escaping out of
cooler is about 208oC.
iii. Grate Cooler operationThe grate cooler operates with a cross current principle in which the
clinker moves horizontally while cooling air blow in from below through
the grate and clinker layer.
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As the hot clinker falls from Kiln, it forms clinker bed on the grate plates
and is than transported through the cooler over alternatively fixed and
reciprocating grates. At the inlet of Cooler House, clinker is quenched and
spread evenly across the cooler width by the cooling air. The grate is
fabricated in order to obtain a thick clinker layer and a uniform
distribution of air through the clinker bed in the interest of heat recovery.
During the clinker transportation
from the cooler, a part of dust and
small size clinkers fall off from the
grates and get collected into
hoppers under the grates. These
hoppers have dust bin valves attheir bottom which opens only
when a certain weight has been
reached. The dust is released in the
same DBN conveyors which carry
the clinkers. The drag chain and
rotary air lock system feed these
clinkers and dust to clinker
transport system. A dust collecting ESP is also installed known as cooler
ESP. Exhaust gases from collection is fed to the ESP for dust collection.
iv. ConstructionCooler parts are as follows:
IKN Grate (fixed) - IKN kids, Fans
Cooler I-IV Grate - S.S Grate plates, S.S Bolts
Cooler Fans - Fan, Belts, Pulley, Motors
Hammer Crusher: - Hammers, Pans, Rollers
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IKN Grate
It is a stationary grate plate. Previously, there
used to be similar S. S Plates in place of IKN
plate but a change was made by the productiondepartment. They are not only having a
guaranteed 1 year life but also have increased
the production of Unit-2.
IKN-KIDS
There are 6 to 8 stationary and stepped enclosed air beams. These air
beams are aerated by individual ducts. Refractory side dams are used to
collect and aerate segregated clinker from discharge. Air blasters are
used to avoid snowman formation.
S.S Grate Plates
These plates are of old design. It
has holes over it with air blowing
from below. Due to air blowing
with heavily from below causes
widening of air holes which causes
clinker to pass from it to lower
chamber where rollers
reciprocating the plates are
placed.
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Fans
For Cooling purposes high efficiency fans are placed below over the
ground which suck air and send it for cooling
Cooler Fan
Maker REITZ
Fan Capacity- In/Out 46190m3/hr,
45360 m3/hr
Pressure 4.7 KPa
RPM 1480
Hammer
At discharge end of cooler hammer crusher is provided consisting of a
rotor with shaft. Hammers are mounted on each row. Hammers are
casted out of high chrome or manganese steel. Clinker is crushed to a
size of 15-25mm by Hammer Crusher.
v. MaintenanceShutdown Activities
All Cooler Grate Plates, Side Blocks should be checkedIf we find that the Grate Plates have worn off too much by
abrasion action of clinker or high velocity air gushing from below
than it is replaced. During my visit this operation was going in the
Cooler House. The old Grate Plates had their holes widened due
the high velocity air and also the thickness of those plates was
reduced due to the Clinker abrasive action. The replaceable lip is
also checked. A lip is provided in order to hold the side grate
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plates. These plates in a row are welded to each other and any gap
bigger than 3 to 5 mm is filled between the Grate Plates.
All compartment internals as pull rod, single and twin supporting rollersand grease lines should be checked.
All Grate connecting rod and non-drives must be checked Dust valve hopper leakage should be checked for holes etc which needs to
be patched and under Grate compartment jail needs to repaired/replaced
Just below the Grate plates there is a net type arrangement which
is used to allow the dust to fall into hopper connected to dust
valves. This net sometimes gets clogged by large clinkers which
need to be removed. Also sometimes they may create a hole in the
hopper causing leakage.
The net over the leaking hopper
is cut in this and the hopper is
thoroughly checked for holes and
repaired.
Hammer crusher hammers, impactplates, lining needs to be repaired/
replaced
Hammers get worn off due to
continuously striking the clinker and
breaking it to smaller pieces. The
hammer are either replaced or used
again by reversing them.
The impact plate just below the crusheralso gets worn off by continuously
striking clinker over it. There might be
holes created in them. The size of the
crushed piece can also be set by a screw
provided for changing inclination of
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impact plate.
Also hard basing is done at the end of the Cooler House so as to
protect it from continuous abrasion taking from the moving
clinker. The welding alloy LH 745S is used for this purpose itprovides hard surface at high temperature.
Pan conveyor or damaged track wheels should be checked and changed. Under Grate beams etc. should be checked All Cooler Fan Belts, bearing, Impellers should be checked.
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A.Company ProfileName of the company : Bokaro Steel Plant (SAIL)
Establishment Year : 1972
Chairman : Mr. S.P Verma
No of Employees : 25000
Products
Production Capacity : 4.3 MTPA Steel
Products
CokeAmmonium Sulphate
Naphthalene
Crude Anthracene
Road Tar
Crude Benzol
Nitration Grade Benzene and
Toluene
Solvent Naphtha
Light Pyridine
Ferrous Sulphate
Pig Iron
Steel
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B.IntroductionBokaro Steel Plant, the biggest steel complex in India, was designed with
the collaboration of former USSR. It is one of the main units of Public
Sector Organization, Steel Authority of India (SAIL). Bokaro Steel City is
situated on the bank of river Damodar in the North, river Garga in the
East, Chas-Ramgarh road in the south and Muri -Chandrapura line in the
west. It is about 50 kms from Dhanbad, which is on the main Delhi-
Howrah Railway line. It has been long acknowledged that Bokaro would
be one of the best possible locations for a large sized Iron & Steel Plant.
Its present capacity is 4.3 MT and is rapidly modernizing itself to double
its production. At present it is working with 5 Blast Furnaces and 8 Coke
Oven batteries.
Units of Bokaro Steel Plant
1. Raw Material & Handling Plant (RMHP)2. Coke Ovens3. By Product Plant4. Sintering Plant5. Blast Furnace6. Steel Melting Shop7. Slabbing Mill8. Hot Strip Mill9. Hot Rolled Coil Finishing
10. Cold Rolling Mill11. Roll Grinding and Bearing Shop12. Slag Granulation Plant13. Scrap & Salvage Department14. Refractory15. Research & Control Lab16. Inspection & Quality Control17. Industrial Engineering Department18. Water Supply19. Oxygen Plant20. Acetylene Plant
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21. Protective Gas Plant22. Machine Shop23. Forge Shop24. Structural Shop25.
Steel Foundry26. Pattern Shop
27. Ingot Mould Foundry28. Iron & Copper Foundry29. Thermal Power Plant30. Production Planning & Control
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C.Brief Description of UnitsVisited
I. Raw Material & Handling PlantPurpose:
1. To obtain homogeneity ofchemical and physicalcomposition of different raw
materials received from
different sources by method of
blending.
2. To keep an optimum stock ofmaterials in order to take care
of irregularities of supplyarising due to strike in railways, mines etc.
3. To release the wagons irrespective of consumption of material bycustomers. Thus, it avoids the demurrage charges.
II. Coke OvensMetallurgical and Engineering Industries generally require coke as fuel.For the production of solid, porous, coke ovens of certain characteristic
properties needed.
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In Bokaro Steel Plant, coke is chiefly used as fuel and for reduction of
iron ore. The Coke Oven here is largest in India. It has got 8 batteries at
present. Each battery contains 69 ovens.
The process of making coke consists of the destructive distillation of
coal in the absence of air. The coal is heated in closed chamber thereby
driving out the volatile components present in the coal and leave
behind the residue called coke. This phenomenon is called as the
carbonization of coal. The carbonization of coal can be carried out at
different temperature depending upon the type of coke we need.
Different sections of Coke Oven plant are:
1. Coal Tower2. Coal Handling Plant3. Coke Oven Battery4. Coke Sorting Plant
III. By Product PlantThe high temperature carbonization of coal is basically adopted for production of
metallurgical coke for use in Blast Furnace. The gas so produced is also used as fuel
for making, shaping and treatment of steel after detailed process of cleaning to make
it suitable for plant uses. In the process of cleaning some primary by-products,
namely crude tar, benzol, ammonium sulphate etc are obtained. The primary and
secondary chemicals that can be produced from these are of great importance for
the growth of chemical industry.
IV. Sintering PlantIt has been found that the production rate can be increased if the raw
material is sent into the Blast Furnace in sintered form. Keeping this in
view, BSL has the largest plant in India. There is provision for partially
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cooling the sinter on the machine itself. The ignition furnace is of double
hearth and provision is there for adding extra amount of coke on the
topmost layer of the charge. This plant not only helps in supplying a
suitable charge for the Blast Furnace, but also eliminates other intricate
problem.
V. Blast FurnaceIt is the root plant of any steel producing complex. It is the unit where
reduction of Iron Ore takes place. Hot metal is the final product from
the Blast Furnace. There are five furnaces, each of capacity 2640 Tons/
Day with a useful volume of 2000 cubic meter. The annual capacity of
Blast Furnace is 4.82 MT.
VI. Steel Melting ShopThe raw material for the Steel Melting
Shop is Hot Metal coming from Blast
Furnace. Here pure oxygen is blown
into the hot metal. Impurities are
oxidized and metal is transformed
into steel.
The Steel Melting Shop at Bokaro is
largest in India with an annual
production of almost 4.3 MT. There
are 5 LD Converters in SMS 1 of 100 T each where as in SMS 2 these LD
converters are of annual capacity of 300 T each. The steel produced is
meant for plates and sheets.
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VII. Auxiliary ShopsThe main function of Auxiliary Shops of
Bokaro Steel Plant is to extend help in a
specified manner to the principal
production line by producing spare parts
to exact specifications. The objective of
the set up of various Auxiliary Shops is
the economization of the production
complex and/or easy running of the production process. Some of these
Shops are as follows:
1. Ingot Mould Foundry2. Steel Foundry3. Forge Shop4. Machine Shop5. Structural Shop6. Pattern Shop
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D.Detailed DescriptionI. Raw material and handling plant
This plant deals with the raw materials which are coming from various
sources. It deals with around 10 MT of raw material per annum that
amounts to about 400 to 500 wagons which has to be unloaded per day
with each wagon carrying 60-70 tons per wagon. Mr. R.R. Kumar (AGM
RMHP) described about the plant and gave an introduction about its
operations and functions.
a.Functions of RMHP1. Unloading of Raw Materials within a given time
The material which comes within the plant by the well spread railway
routes within the plant has to be unloaded as quickly as possible. For
this purpose Tipplers are provided in the yard where each wagon is
uncoupled and placed inside the Tippler and tilted to be emptied. The
amount of wagons which have to be emptied is so much sometimes
that they have to remain docked in the yard for days and because of
this reason the company has to pay a heavy leverage of 10 15 Crores
each year.
2. Storage with proper blendingThis function is achieved by two types of machines Stacker and
Reclaimer. To keep the plant running we need continuous supply of
raw materials which is achieved by stacking them in 18 different
beds. Since the quality of material may differ hence blending is
needed. Stacker distributes the material in piles horizontally using
boom conveyors. so when Reclaimer reclaims the material, it takes
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the entire pile at a time hence blending the different composition or
material together.
3. Supply to Internal CustomersThese are the following Internal Customers of RMHP
1. Refractory Material Plant (RMP)2. Blast Furnace3. Sintering Plantb.Types of raw material
c. ProcessThe Raw Material coming from different parts of the world reaches
RMHP via rail routes to the captive yard inside RMHP. At this yard
there are 4 Tipplers located whose function is to unload the raw
materials. There are 3 cradle tipplers and 1 hydraulic tippler. Thecradle type tippler has a cradle located at top and on 1 side on which
the BOX wagon rests while it is being toppled by an angle of 170
where as the hydraulic tippler holds the wagon by hydraulic arms
and topples it. The cradle type unloads a wagon at the rate of 20
wagons/hr where as the hydraulic type unloads it at the rate of 12
RAW MATERIAL SIZE SOURCE
Iron Ore Lump
(Hematite)
10-40 mm Kiriburu,
Meghanathburu
Iron Ore Fines
(Hematite)
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wagons /hr. But the cradle type Tippler may cause damage to the
wagons which may increase railways cost of material handling and is
quite noisy.
There is a R & C sampling lab also known as Yard Lab nearby
consisting of equipments such as jaw crusher, evaporator etc. This
lab takes sample from each rake (59 wagons) of material arriving at
the yard. They do the physical size test and classify the material as
fines and lump. For chemical test the material is converted to a fine
powder and sent to the R & C Lab where a spectrometer test is done
in order to determine the composition of the raw material. This is
done so as to maintain the quality of the raw material.
Below each Tippler there are two hoppers located which empty the
raw material over to oppositely moving conveyor belts which empty
it in a chute moving over a conveyor which carries it to the junction
house. The junction house than decides where the raw material has
to be sent. There are numerous junction houses within the plant
which keeps the track of material movement. Each junction house
has 3 conveyors moving in each direction in which 2 are used and 1
is kept in case of breakdown of one of them.
The junction house sends the material for stacking in 18 beds
(280m*27.5m*9m) with the help of double boom stackers. The raw
material in beds is as follows:
Bed 1 Sinter (It could be either purchased sinter in
case of shortage or it could be for storage
during breakdown)
Bed 2 to 6 Iron Ore Fines
Bed 7 to 10 Iron Ore Lump
Bed 11 to 14 Flux for Sintering Plant
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Bed 15 to 17 Materials for RMP
Bed18 Sinter, L.D, Slag, Corzite
There are 2 stackers for Bed 15 to 18 and rest 4 stackers for Bed 1 to
14. These stackers moves between the bed and could be moved from
one position to other by placing it on a platform. These stackers
could stack at the rate of 1200 Tons/Hr. Similarly there are 6 barrel
type Reclaimers, 1 Bucket Wheel Reclaimer and 1 Shovel and
Travelling Reclaimer which are used for reclaiming the raw material
and sending it to the customers. The Barrel Type Reclaimer reclaims
the material at the rate of 1000 Tons/ hr and Bucket Wheel
Reclaimer reclaims at the rate of 500 Tons/ Hr.
There are screening units for limestone and lump ore within the
RMHP. The raw materials have to travel miles within the plant so
there is possible breakage of materials hence they have to be
screened before sending it to the internal customers since the size of
material is very important during charging. The capacity of both
screens is 500 Tons/Hr.
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II. Blast Furnace and Pig CastingMachine
a.Raw materialMATERIAL SOURCE
Iron Ore RMHP
Coke Coke Oven
Sinter Sintering Plant
Limestone RMHP
b.ProcessThe raw materials (Iron Ore, Coke, Sinter, Limestone etc.) are carried
to the blast furnace by conveyor belts from their respective sources
(RMHP, Coke Oven, Sintering Plant). The notable part during
charging is the size of the charge. Hence the fines and the lumps of
ores are separated in the RMHP itself. Further during material
handling of raw materials there is fine generated at different levels
so there are Vibrating Dust Separators at the start of the Blast
Furnace from where fines are separated and sent to the sinter plant
to be converted into Crude or Spongy Iron.
The raw material is emptied into their respective hoppers until they
reach Skip Pit where the raw material is weighed by weighbridge and
is loaded in the Skip (13.5-14.5 m3). In a Shift maximum 45 charges
are done with each charge having 20 skips. A same schedule is
followed for each charge. There could be a positive or negativedifference of 500 Kg but the total raw material in each charge
remains the same. The Skip moves over the rail in the skip bridge
and empties the contents at the top of the Blast Furnace. The skip is
operated by means of the skip wrench located in the wrench house.
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The hot blast is supplied from the stoves to the bustle pipe and is
blown through the tuyers at the bottom of the Blast Furnace
respectively located in the Cast House. The molten Iron and Slag flow
through the iron runner and the Slag runner. These runners are
made up of refractory powder (CaCO3, Al2O3, and SiO3) which needs
to be rebuilt after every 2 months. A new L&T furnace has a Siphon
Hall which sucks and separates Slag from the Iron thus there is no
need of two different tap holes. Just beneath the Cast house, at the
end of the runner there is a ladle wagon run by a locomotive which
carries the molten Slag to a Slag yard where it is stored in pits and
molten Iron to SMS. About 5% of this Pig Iron is sent to the Pig
Casting Machine (PCM). At the end of each runner there is manually
controlled swivel and rocker type runner which helps in pouring themolten material in ladles.
The waste gases from the blast furnace are taken through uptakes
and gas outlets to the dust catcher and further to the Gas Cleaning
Plant (GCP). This cleaned gas is taken through gas pipes to the stoves
for heating the blast pipes. There are checker plates in it which can
me made of refractory material or graphite which gets heated up and
the heats the cold blast sent by turbo-blasters which is sent to Bustle
pipe. The gaseous products of combustion evolved in the hot blast
stoves are exhausted through the chimney.
c. Blast FurnaceThe foundation has to carry a very heavy load. It constitutes piles
driven to the bed rock over which a huge reinforced concrete
structure is constructed. The steel columns mounted on the concrete
ring support the mantle ring. The Blast Furnace shell and the insidebrickwork is supported by mantle ring. The hearth bottom consisting
of fireclay bricks and carbon blocks is laid out within concrete ring.
The hearth is a cylindrical portion where the iron slag notch and
tuyers are located. The bosh is the section which slopes outwards
just above the hearth. The body is again a cylindrical portion above
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the bosh. The shaft which is in the form of a cone comprises the
portion above the body. The throat cylindrical in form is at the top of
the shaft.
There are box type coolers within the refractory lining of the throatand shaft through which water circulates. The coolers are mounted
to the shell of the Blast Furnace. The bottoms of the hearth and side
walls are having plate type coolers.
In 2000 m3 Blast Furnace, the Iron notch is situated at the height of
1.1 m above hearth bottom. The slag notch is located at a height of
1.8 m above iron notch. The tuyers through which the blast is blown
are located at a height of 3.4m above the iron notch. Hot blast from
the stoves passes through the Bustle pipe and tuyers (28 no.) into
Blast Furnace. The Bustle pipe is located at a height of 5.5m above
the iron notch. Another important feature of the recently
modernized Blast Furnaces is Coal Dust Injection System (CDI).
Previously the company was planning to replace the old coke based
furnaces by gas based furnace due to poor availability of
metallurgical coke and high cost of import of metallurgical coke from
Australia and New-Zealand. But CDI reduced the present
consumption of coke by 50%.
The charging mechanism is Bell Less Type. These systems use
multiple hoppers to contain each raw material, which is then
discharged into the blast furnace through valves. These valves are
more accurate at controlling how much of each constituent is added,
as compared to the skip or conveyor system, thereby increasing the
efficiency of the furnace. Some of these bell-less systems also
implement a chute/bin in order to precisely control where the
charge is placed. This valve system is easy to control and have
replaced the old Bell Systems. In the Furnace, a stirrer is placed for
equally distributing the raw material inside. A Bleeder Valve is
placed at the top of the Blast Furnace to release pressure if it exceeds
10000kg also a wench is provided to open it as and when required.
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In the cast house, the electric mud gun, tap drilling machine and the
slag notch stopper is located. Tap Hole drilling machine is used for
drilling out and opening the Hole (iron notch) for tapping the hot
metal. The closing of the hole at the end of tapping is accomplished
by means of clay gun. The opening and closing of slag notch is carried
out by the slag notch stopper.
Reduction by means of CO begins in the shaft and proceeds in steps
from the highest Iron Oxide (Fe2O3) to the intermediate oxide
(Fe3O4) and further down to the lowest oxide (FeO).The reaction
between FeO and CO is
FeO + CO = Fe + CO2
This is called indirect reduction of the iron and takes place around
600-1000 C. The chemical reaction between FeO and solid C is:
FeO + C =Fe + CO
This is called as the direct reduction of Iron and takes place around
1100 C. Usually 50-60% of iron is reduced in the blast furnace by
indirect reduction and 40-50% by direct reduction. This metallic iron
formed initially is in the solid state since the melting point of pureiron is 1540 C
The carburization of the spongy metallic iron takes place in the
presence of CO and its melting point is lowered to around 1200 C.
This carburized iron with about 2 % C melts and drops through the
incandescent coke on the wall of the wall of the furnace hearth. At
this time the iron absorbs more carbon up to 4% and settles at the
hearth bottom as liquid pig iron.
The reduction of Manganese, Silicon and Phosphorous from the
charge takes place in the furnace simultaneously with the reduction
and carburization of Iron. These elements also go over into the pig
iron.
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The slag forms at the lower part of the shaft due to the oxides of Iron,
Lime, Silica and Alumina. Liquid ferrous slag is formed at 1200 C and
at a certain proportion of the above oxides. As it moves down into
the hearth, it is heated and dissolves coke ash, fluxes and the
remainder of ore gangue
The production of each Blast Furnace is about 2600-3000Tons/Day.
d. Pig Casting MachineAbout 5% of the production of Blast Furnace is sent to PCM because:
1. Poor quality of Hot Metal2. SMS Breakdown3. Excess production by Blast Furnace & SMS not able to process
the entire lot.
Vital Equipments are:
1. Wagon Shunting Wrench2. Ladle Shunting Wrench3. Ladle Tilting Wrench4. Belt5. 4 PCM6. 2 Lime Preparation Plant (LPP)
The molten material comes to the PCM via Locomotive and than a
ladle shunting wrench is used to pick the ladle and place the ladle for
pouring where another wrench tilts the ladle over a conveyor belt
with pig cast coated with lime. The lime sprayed over the Pig Cast
does not allow the Pig Iron to stick to the cast. Water is sprayed over
the Pig Cast to cool it as the conveyor is moving. Just beneath, whereporing takes place over the Pig Cast, there are plates below which
dont allow the splashing to damage the machine elements below.
The splashed metal is again taken for pouring by a skip. This
prevents the loss of material.
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Limestone is used to prepare the Lime by mixing it with water. A
large amount of heat is evolved during this process. This is pumped
to the Lime sprayer which sprays it over the Pig Cast from below.
This process is continuous with the conveying action. The Pig Cast is
kept in the Cold Pig Yard and can be transported using Locomotives.
There are 4 electromagnetic cranes having 10 Ton capacity each
which are used for transferring Pig Iron to the Wagon.
At the time of my visit the PCM was closed for maintenance.
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III. Machine ShopIn order to keep the plants
continuously in working conditioneach plants have their own Area
Repair Workshop which deals
with the specific maintenance
problem of that Plant.
The Machine Shop is the Centre
Repair Workshop where parts are
given final touches. It has got 4
Bays, LE (Light Engineering), ME
(Medium Engineering), HE (Heavy
Engineering) and Assembly Bay. Each Bay has got an overhead Crane
with a capacity varying from 5 tons to 30 tons.
LE Bay houses simple lathes and turret lathes with bed length varying
from about 1m to 3.5m. It also has small size gear hobbing machine and
milling machines.
ME Bay houses medium size gear hobbing machine, Gear shapingmachine etc.
HE Bay houses Asias largest vertical boring machine with stroke length
of 4m. It also houses other large size vertical and horizontal boring
machines.
The Assembly Bay is the place where the parts are assembled and final
product is ready for dispatch.
Near the Machine there is another shop Structural Shop which houses
an Annealing Furnace which is used for annealing large size ladles etc.
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IV. Forge ShopThe Forge Shop is a part of auxiliary shops of Bokaro Plant. It takes its
raw material from Steel Foundry and from outside as per specificationand supplies it to the internal customer Production Planning Shop (PPS)
which gets the further work done by Machine Shop
a.Machines
b. ProcessThe job is first heated in the furnace at about 1200-1250C just below
the melting point of iron. Then it is picked up by crane incase the job
exceeds human holding capacity and the pneumatic ally driven jaws of
manipulator holds it. The manipulator jaws are pneumatically driven
and not hydraulically because we require impulse action in the jaw
arms of manipulator. When the hammer strikes the job, the job applies
impulse force over the jaws which if hydraulically driven remain rigid
hence the job breaks where as the pneumatically driven hammers are
flexible to impulse force and leaves and holds the job immediately as
Steam & Air Forging Hammer NO
5T 1
3T 1
2T 1
Pneumatic Forging Hammers
1T 2
4T 2
25T 2
2 Ton Forging Manipulator 2
1 Ton Forging Manipulator 2
Band Saw 1
Bogie Hearth Furnace 3
Box Type Furnace 2
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hammer strikes. The manipulator moves over the railroad by a
mechanical drive and because we require accurate movements of arms
of jaws we use hydraulically driven mechanism.
During forging due to heavy forces over the job its crystal structuredistorts which is improved by heat treatment. Sometimes a job becomes
soft on cooling in case of copper where as sometimes the job becomes
hard in case of iron. Hence annealing and seasoning is done later for
proper hardness of the job. The hardness is checked by the Inspector
who pierces the job and checks the depth and measures it with the
standard. Sometimes rough sizing of job is also required in that case the
Forge Shop has a band saw which cuts the job in blanks. Sometimes the
job is not required immediately but after a period of time. In that casethe job is sent to open entry where they are seasoned in open to
improve the crystal structure of the part.
There are two types of furnaces present in the shop
1. Bogey TypeThis type of furnace is used for heating the job entirely at a
single time. There is a bogey in which the job is placed and it
goes inside the furnace.
2. Box TypeThis type of furnace is used if the job is not to be heated
entirely i.e. a part of it is kept outside and part of it is heated
in the furnace.
The fuel which is used in the furnace is Coke Oven Gas and Oxygen in
the ratio of 1:4 and small amount of Hydrogen.
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A centre core is also prepared from High Silica Sand and additives. The
mixture is prepared as follows:
1. High Silica Sand : 100 Kg2.
Part A (Binder) : 20 Kg
3. Part B (Hardener) : 1 Kg4. Part C (Accelerator) : 4 Kg
The mixture is thoroughly mixed and it is placed inside the Core Box but
it is not rammed. It sets itself to the size of the pattern and thats why it
is known as self setting sand. It is than sent to 3 ovens where it is heated
with CO gas for 10 hours and than it is cooled for 1 hour inside the oven
and 1 hr outside the oven. The stopper dryer is than used for drying the
core by keeping it at 100-120 C for about 48 hours.
The mold is prepared from the two parts the drake and the copes After
these two things are prepared than the mold is prepared by placing the
prepared core over the drake and keeping the cope over it. A sheet
pattern is placed in between the core and case of cope. The molding
sand is sand now filled in between the core and the case and rammed by
sand slinger.
Now as the mold is prepared, hot metal coming from the Blast Furnaceis poured in the mould through the runner and the gate present in the
mould and it is kept for solidification for about 72 hours. Later the cope
and drake is lifted using a cope lifting machine. A 5 % coal powder is
added in the additives in molding sand which when comes in contact
with the hot metal causes a gaseous layer to be formed between the
casting and the sand. The graphite paint is also applied over the molding
sand which prevents the sand fusion.
To collapse the core, we strike the casting over iron pillars and thus the
core collapses and breaks away.
It must be noted that Silica Sand cannot be used for molding basic
materials (Magnesium etc.) since Silica Sand is slightly acidic. For this
purpose Olivine Sand is used which is generally found in Europe.
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After the Ingot Mould is prepared the milling operation is performed
over the ends of the molds to remove the bulges or extra material
attached.
Finally, the Ingot Mold is placed over bottom plate. This bottom plateacts like a reinforced plate for holding the Ingot Mould and sent to Steel
Melting Shop (SMS).
The Ingot Moulds have a life of about average 25 castings.
The Ingot Molds are of following specification:
1. 17 Ton2. 20 Ton3. 25 Ton4. 28 Ton
The first two are having ribs so that the Ingot formed gets ribs for
holding it in Slabbing Mill.
There are two other foundries namely:
b.Iron and Copper FoundryIt is where non-ferrous alloys such as copper, brass, zinc and aluminum
as well as Cast Iron casting are done.
c. Steel Foundry :The foundry takes scrap steel from the SMS and use it for its casting
purposes.
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VI. Steel Melting Shopsa.Steel Melting Shop (SMS)-1
The Steel Melting Shop-1 consists of 4 L-D Convertors which is used for
converting the Hot Metal from the Blast Furnace into Ingots.
Process
The process of converting hot metal into is a 5 step process. It is as
follows:
1. Hot Metal from the furnace is supplied by rail routes to SMS-1 throughladles to Mixer Bay Mixer which use CO gas as fuel. The furnaces are
preheated to about 1300 C to prevent metal sticking to the furnaces.
This heating is done in order to prevent the hot metal sticking to the
ladle. This is done in order to homogenize the old hot metal and the new
feed.
2. The Hot Metal is sent to the LD Convertor via ladles (5 No each of 130Ton) which reduces the C % to .10 to .15 %. In this Limestone and
Dolomite is added to remove the impurities in the form of slag. Oxygen
blasting is done in order which causes the impurities to burn away by
forming oxides and the proceeding chemical reaction causes the
temperature rise.
3. After conversion is completed, tapping is done. During tapping, Ferro-Mg and Silicon-Mg is added to remove oxygen which can cause blister to
be formed in casting. If the carbon percentage has decreased too much
than re-carburization is done using coke bags which is purged through
Argon Gas.
4. After tapping is done in the ladle, the ladle is lifted using cranes andtapping is done using sliding gate mechanism. The gate is opened which
is fitted below the ladle and the mould is filled. Aluminum shots added
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to the casting if oxygen content is found to be high since it forms Al2O3
which is lighter and floats over the surface.
b.Steel Melting Shop (SMS)-2 & CCSThis is a new shop which is set up in conjunction with continuous
casting shop. The process of conversion from hot metal to steel is same
as in the case of SMS-1. The only difference is that here we have only 2
converters instead of 5 in SMS-1 but of higher capacity of 300 Tons.
In continuous casting shop we have a Steel Refining Unit in which the
refining of steel is done. It is used for heating a ladle of 300 Tons at a
time using an electric arc. The Aluminum bricks are added which are
used for removing oxidized material from the crude steel also the
refining of other elements such as Cr, Mn etc is done. The ladle is than
kept over a car and sent to the continuous casting machine over which it
lifted by crane and kept over high Cr manganese pipe which could
sustain higher temperature. This fluid as flows starts solidifying and
passes through the mold thereby taking the shape of slab. Now it is cut
to the actual size by means of acetylene gas. The Slab is than send to Hot
Strip Mill to produce steel rolls upto thickness of 2 mm which is later
sent to the Cold Roll Mill for reducing its thickness to .15 mm.
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VII. Coke Oven and BPPThe main purpose of the coke oven is to provide blast furnace quality coke to
the blast furnace. During the process of coke preparation a large amount ofvolatile material and dust escapes which is processed in the By-Product Plant
which to give a range of products which are used in various fields like
pharmacy, roads, railways etc.
The coke arrives via rail routes to the tippler (2 No which unloads in the
similar fashion as in the case of RMHP and send via 2 conveyor belts to the
Silo. There are 81 Silo. These Silo's are numbered from 1 to 53 odd numbers, 2
to 54 even numbers and 1A to 53A odd numbers. Capacity of each Silo is 2500
Tons. Each Silo consists of coal coming from a different source namely
Australia, New-Zealand, Karghali, Kathara, Moonidi, and Jharia etc. These coals
have different ash percentage and different volatile material. The captive coal
mines of the SAIL produces coal of various qualities having ash percentage
between 15-25% where as the imported coal have ash percentage between 7-
8%. So accordingly these need to mix in order to obtain coke. The Indian Coal
and imported coal are mixed in the ratio of 1:4 almost. From the Silo the coal
is sent to Hammer Crusher which has a capacity of crushing 350Tons/Hr.
which crushes the coal to about -3.2 mm size. The homogenization and mixingof coal used to occur via mixture but now it is not anymore used. The mixing
occurs automatically when the coal is transferred through several conveyor
belts. From t
The crushed coke is transferred to Coal Tower (4 no's) with each having a
capacity of 3200 Tons. From there the coal i supplied to the 8 Coke Oven
Batteries.
Coke Oven Battery consists of 69 coke ovens and 70 heating walls. In eachCoke Oven there are 3 charging holes on the top and is charged by the
charging car. On the side of the Coke Oven one would see a huge Push car
which is used to ram out the coke prepared in the oven. The leveling ram
levels the top of the coal. On the other Side one would see the Guide car which
supports the rammed column of coke and guides it to the quenching car.
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The Coke Oven walls are made up of refractory material having hole in
between through which the Coke Oven Gas and Blast Furnace Gas as a fuel are
burnt which causes the bricks to become red hot. There is no air inside the
oven so the coal burns without air at about 1200 C. The flue pipes of the
refractory tunnel s connected by the flue tunnel with Twin reverse valve by
help of which flow reverses after some time. The two heating walls are
connected over the top by means of pipes. It carries the burnt gas out through
the chimney. The top of the coke oven is connected by pipes coming out which
is connected to the pipe which carries the burnt particles and volatile particles
to the By Product Plant.
From the coke oven it is sent for quenching in Quenching Tower where water
is dropped from the overhead pipe. The Quenched coke is sent for CokeCrushing Station and than to Coke Screening Station from where the coke of
25 mm size is sent to Blast Furnace and coke of size between 25-80 mm is
sent to crushing station again.