vizag steel plant
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VIZAG STEEL PLANTABSTRACT
Steel has always been the backbone of nation's economy. From an annual
production of 13 million ton in 1900, global steel production raised to 300 million ton in 1950
and to 842 million ton in 2000. India produces 30 million ton per annum from 9 major plants.
The major steel plants contribute 19 million tones and the rest is contributed by secondary
sector. Visakhapatnam Steel Plant is one of the 6 integrated steel plants contributing 3.51
million ton of liquid steel per annum. It is the only steel plant in India accredited with ISO 9001,
ISO 14001, and OHSAS 18001 certificates for Quality environment and Safety aspects of the
steel making activities. With the improvement in operating performance of major units and
efficient maintenance and material handling system the plant has made a turn around and
achieved net profit of 2100 crore rupees during the current fiscal 2004-05.
This project deals with the Design verification of critical Trunnion ring of a process
equipment LD Converter used for steel making process. The LD converter is a steel shell lined
with refractory material used for handling the molten steel at 1650° C. The vessel is suspended
on a trunnion ring with four numbers of tie rods and rotates at 0.1-1.0 RPM by means of four
hung reducers and one special reducer with motors of 4 - 172KW DC. The trunnion ring is box
section with plates 140mm having forged end journals and the entire assembly weighs around
147 Tons carrying 1000 Tons of vessel with hot metal. The linear dimension of the trunnion ring
will be around 14 Meters and the straightness of the surface should be 1 mm over 1000mm
span. General norms of the life of the trunnion is around 1 0 Years but the it is to be changed
with the survey readings if the deformation exceeds the limit. In converter No.1, the survey
readings depicted around 20mm deformation and is to be changed in a planned shutdown as
the repair takes around 40 days shutdown of the process equipment. Keeping this in mind a
new trunnion ring was imported from the Russia and is observed the changes in the design
compared to the existing trunnion in the hole sizes 0300 fTom 0180. It is necessary to verify the
design before implementation about the safety of the system.
In this regard after visiting the site and collecting the necessary dimensions a
3Dimensional modeling using CATIA has been done for the existing and modified design. Also
the model has been imported to ANSYS and the von-mises stresses have been obtained by
applying fixed support constraint
and loading conditions and the stresses induced in the trunnion ring is around 25.32 N/mm2 in
the existing trunnion and 36.5 N/mm2 in the modified trunnion ring. With the material of
ASTM-A36 of the trunnion, the existing Factor of safety is reduced fTom 11 to 8 and as per the
norms for the structural the allowed factor of safety shall be above 5. Hence the design is safe
for the operation. The data is presented with 3D model of objects, meshed images and von-
mises
stresses. The present analysis was done only in static case. This can be further
extended to dynamics considering the rotation of the trunnion ring. As the technological
developments are taking place in steel making process there is an
. ample scope of adopting new design Russian LD converter trunnions with the
adoption Top cone water cooling system coupled with bottom bath agitation facilities which
require bigger hole sizes in the trunnion end journals, the designs become critical and requires
thorough analysis.
SOCIAL RESPONSIBILITY
Peripheral development and special concern for the displaced persons underling the
Visakhapatnam steel plant's commitment and concern for the social and regional development
around it. As a special gesture for the welfare of the displaced persons, Visakhapatnam steel plant
provided them with over 5,900 jobs, which constitute more than 1/3 of its total non-executive
manpower. In the recruitment policies of VSP displaced persons have been given several
concessions in the areas of educational qualifications, age and skill levels. As a part of social
responsibility VSP took a massive afforestration program has been launched in and around the
plant. Out of the total 9,200 hectares of area 3,600 hectares has been ear marked for afforestation.
Along the land boundary of VSP a green belt of half a kilometer has been delineated for
afforestation. 1.4 lakh trees have been planted in 100 hectares during 94-95 and 1.22 lakhs of
trees has been planted in 207 hectares during 95-96.3 million trees for 3MT of steel was the
slogan ofVSP.
That target also achieved. VSP has been complying with statutory standards of
both Andhra Pradesh pollution control board and central pollution control board. It has been
closely maintaining 31 major stack emissions and 8 ambient air-monitoring areas out side steel
plant. I
. Mission and Core values of VISAKHAP A TNAM STE
PLANT :.
-
Vision:
To be a continuously growing world-class company.
We shall:
.:. Harness our growth potential and sustain profitable growth.
.:. Deliver high quality and cost competitive products and be the first
choice of the customer.
.:. Create an inspiring work environment to unleash the creative energy
of
people.
.:. Achieve excellence in enterprise management.
.:. Be a respected citizen, ensure clean and green environment and
develop vibrant communities around us.
Mission:
To attain 10 million ton liquid steel capacity through technological
up- gradation, Operational efficiency, to produce steels of international
standards of cost and quality to meet the aspirations of the stake holders.
Core-values:
.:. Commitment
.:. Customer satisfaction
.:. Continuous improvement
.:. Concern for environment
.:. Creativity and innovation
OVERVIEW TO VIZAG STEEL PLANT
GENERAL SURVEY OF IRON AND STEEL MAKING IN INDIA
India is the third largest producer of iron and steel in the common wealth nations
(surpassed only by the UK and Canada) and is 16th among the steel producers of the world. At
present, India's capacity of steel production is nearly
1.5% of the total world production.
The Tata Iron and Steel Co., Jamshedpur (Bihar), Indian iron and steel Co., Burnapur
(West Bengal), Visveswaraya iron and steel limited, badhravali (Karnataka) and a few electric
arc furnaces were the only steel plants in India until 1955.three new public sector plants under
Hindustan steel Ltd,. Were established in the period 1955-60 at Bhilai (MP), Rourkela (Orissa)
and Durgapur
(WB). Each of these has their own coke-ovens which supply the large amount of coke needed for
steel manufacturer. The plant at Bhilai and Durgapur employs the basic open-hearth process of
steel making. The Rourkela plant is unique in the fact that it employs L-D process for
manufacturing 75% of steel. The output of the remainder (Le., balance of25% of steel) is by the
basic open-hearth process.
At present there are eight integrated steel plants and about 174 mini steel plants. The
integrated steel plant located at Jamshedpur (TISCO) is the only private sector plant, and the
rest are in public sector. Integrated steel plants in public sector are:
1. Indian iron and steel Co., (IISC,), Burnapur (WB)
2. Viswesraya iron and steel Ltd,.(VISL), Badhravali (Karnataka)
3. Rourkela steel plant (RSP), Rourkela (Orissa)
4. Bhilai steel plant (BSP), bhilai (MP)
5. Bokaro steel plant (BSL), Bokaro (Bihar)
6. Durgapur steel plant (DSP), Durgapur (WB)
7. Visakhapatnam steel plant (VSP), Visakhapatnam (AP).
The visakhapatnam steel plant is designed to produce three million tons of
liquid steel per annum to be converted to 2.656 million tons per annum of saleable
steel. In addition, Visakhapatnam steel plant will produce annually about 5.56 lakh tons of pig
iron and various by-products for sale.
LOCATION:
The plant is located in Visakhapatnam City, which is on the coast of Bay of Bengal.
Visakhapatnam city is an important commercial center of Andhra Pradesh. It has the deepest
port and is one of the principal outlets for country's exporting Iron ore. The city has many large
industries such as the Hindustan Petroleum Refinery, Bharat Heavy Plates and Vessels ltd.,
Coromandal Fertilizers, Hindustan Zinc, Hindustan Shipyard etc. The city is situated on the main
broad gauge railway line between Calcutta and Madras and is well connected with other major
cities and state capitals by rail, road and air. The Visakhapatnam steel plant is located 16 Kms.
to the southwest of the Visakhapatnam Port and is about 26 Ian ITom Visakhapatnam city. The
town ship and the plant have been built on an area of 27,000 acres, between the national
highway no.5 and the Bay of Bengal.
CLIMATE:
Visakhapatnam has warm and humid climate. April to June are the warmest months of
the year and December to February are the coldest months of
the year. The city benefits ITom the Southwest monsoons (June to September) & Northeast
monsoons (October to December). The average annual rainfall is 973.6mm and highest mean
montWy maximum temperature is 37.8 degrees centigrade.
THE DEPARTMENTS:
There are altogether 25 departments in Vizag Steel Plant. These have been divided
into two categories as Core Zone and Service Zone. Some of them are as follows:
Core Zone: Blast Furnace, Coke Ovens, Steel Melt Shop, Mills, Sinter Plant, and
Raw Material Handling Plant.
Service Zone: Thermal Power Plant, Calcined Refractory Manufacturing Plant
Coke Ovens & Coal Chemical Plant:
Coking coal after selective crushing and proper blending
is subjected to destructive distillation (heating in the absence of
air) in the Coke Ovens. After heating for nearly a period of 16-18
hours at a temperature of about
1100°C, coke is obtained and is used as a fuel as well as
reducing agent in the Blast Furnace. The Coke Ovens of VSP are
engineering feats by themselves. They are the
tallest ovens constructed in the country. There are three batteries, each having 67 ovens.
Each oven is having a volume of 41.6 cu.m and can hold 31.6 T of dry coal charge. The
carbonization time is 16 hours. A mixture of blast furnace gas and coke oven gas having a
calorific value of 1000 Kcal/NM3 supplies the heat for carbonization. Another feature is
the dry cooling of coke carried out by the inert gas nitrogen thus, reducing pollution
considerably. Besides, a bio-chemical plant separately undertakes the treatment of
effluents. By-products like benzene, toluene, xylene, naphthalene, coal tar, creosote oil,
pitch, ammonium sulphate and benzol products are also recovered from the coke ovens
gas. VSP produces, among other by-products, pushkala a prime fertilizer based on
ammonium sulphate.
Sinter Plant:
Iron ore fines, coke breeze, limestone and dolomite
along with recycled metallurgical wastes are converted
into agglomerated mass at the Sinter Plant, which
forms 80% of iron bearing charge in the Blast Furnace.
The Sinter Plant comprises of two sinter machines each
having
312 square metres of grate area with a total,
production capacity of 5.256 million tons per annum. Hot sinter, discharged ITom sintering
machine at 900 degrees centigrade, is crushed to 15mm size in a spiked single roll crusher
with a 1300 X 4200 mm rotor. Unsintered grains are liberated as sinter returns.
Blast Furnace:
VSP has two Blast Furnaces with a useful volume of
3200 cu. m. each. Blast Furnace is charged with coke, iron ore
and sinter ITom the top and produces about 5000 tons of
molten iron per day. Its novel circular cast house with four tap
holes ensures continuous tapping of hot metal. There are four
hot blast
stoves for each furnace with a total heating surface of 224000
square metre. The dome is heated to a
temperature of 1450 degrees maximum, while the waste flue temperature is 400degrees
centigrade. The stoves are capable of giving a blast temperature up to
1300degrees centigrade. A mixture of blast furnace gas and coke oven gas having a
calorific value of 1100 KcalINM3 heats stoves. Gas mixing station is provided to mix BF
gas and coke oven gas in required proportion and to get the necessary calorific value.
Separate stations are provided for each furnace. The annual production capacity of these
Blast Furnaces is 3.4 million tons of liquid
lron.
Steel Melt Shoo & Continuous CastinS!:
Three topblown converters, each of 133 cu.m.
Volume, produce a total of 3.51 million tons of liquid
steel per annum. This liquid steel thus produced is
casted in six-4 strand bloom casters. A special feature
in energy conservation is the collection of Converter
gas to be used as a fuel in the plant. The entire molten
steel at VSP
is continuously cast at the radial type continuous
casting machines resulting in significant energy conservation and better quality steel. 100%
Continuous casting on such a large scale has been conceived for the first time in India.
RollinS! Mills:
The cast blooms trom continuous casting department are heated and rolled in the
three high speed and fully automated rolling mills namely Light & Medium Merchant Mill,
Wire Rod Mill and Medium Merchant & Structural Mill, to produce various long products
like reinforcement bars, rounds, squares, flats, angles, channels, billets, wire rods etc.
Technologies adopted at Rolling Mills include world-class Stelmor and Tempcore processes.
MODERN TECHNOLOGY:
Visakhapatnam Steel plant is the most sophisticated and modem integrated steel
plant in the country. Modem technology has been adopted in many areas of production,
some of them for the first time in the country. Among
these are:
1. Selective crushing of coal.
2. 7 meter tall coke ovens
3. Dry quenching of coke.
4. On ground blending of Sinter base mix.
5. Conveyor charging and bell less top for blast furnace.
6. Cast house slag granulation for blast furnace.
7. 100% continuous casting of liquid steel
8. Gas expansion turbine for power generation utilizing blast furnace
top gas pressure
9. Hot metal desulphurisation 10. Extensive treatment facilities of effluents for
ensuring proper
environmental protection. 11. Computerization for process control 12.
Sophisticated, high speed and high production rolling mills.
MAJOR PLANT FACILITIES:
The production facilities in the Visakhapatnam steel plant are most modem
amongst the steel industry in the country. The know-how and the technology have been
acquired from different parts of the world from the reputed and established sources.
Some of the novelties of the Visakhapatnam steel plant are:
1. 7-meter height coke ovens ofVSP are the tallest so far built in the
country. Dry quenching of coke has been adopted which will not only improve the quality
of coke and economics of coke production, but also contribute significantly to the
reduction of environment pollution.
2. Base mix yard for sinter plant introduced for the first time in the
country helps in excellent blending of the feed material to the sinter machine and
production of consistent good quality sinter.
3. With useful volume of 3200 cubic meters each the two blast
furnaces have bell less top charging equipment and 100% cast house slag granulation. The
granulation of the entire molten slag arising at the furnace cast house avoids the need to
transport molten slag and optimizes utilization of slag.
4. 100% continuous casting ofliquid steel into blooms result in less
and better quality of blooms.
5. The VSP have three sophisticated and large rolling mills with the
latest features of automation and optimization.
6. The operations of blast furnaces, steel melting shop and rolling mills have been
entirely computerized to ensure consistent quality and efficient performance.
The major production departments of Visakhapatnam steel plant are the raw
materials handling system, coke ovens, sinter plant, blast furnace, and steel melting shop
and rolling mills.
Extensive facilities have been provided for repair maintenance as well as
manufacturing of spare parts. There is a Central machine shop, Structural shop, forge
shop, foundry, wood working shop and loco repair shop. Visakhapatnam steel plant has
got its own Air separation plant for production of oxygen and acetylene plant for
production of acetylene gas. A captive power plant has also been provided for power
generation with 4 units, three of 60MW generation and one 67MW capacity.
RAW MATERIAL LINKAGES:
The steel plant is getting it supply of iron ore-lumps and fines from the Bailadilla
deposits in Madhya Pradesh, blast furnace grade lime stone from the Jaggayyapeta in
Andhra Pradesh, SMS grade lime stone from Badnapur in MP,
blast furnace grade lime stone from the Kotni-sonor deposits in MP. Most of cocking coal
requirement will be met by imports through the Visakhapatnam harbor while the balance
will come from the Bengal-Bihar area. Coal for power generation will come from Anantha
deposits of Talc her region in Orissa. POWER SUPPLY:
Peak construction power requirements were about 12MV A This was arranged
from the Gajuwaka substation of APSEB at 33KV.
The Plant has in-plant power generation from a power plant having 3 Nos, of
60 MW sets installed. An additional requirement of operational power, around 150 MV A,
is being met from APSEB grid. Operational power supply is initially at 220 KV, which is
subsequently stepped down to 400 KV.
WATER SUPPLY:
Requirements of water during the peak of construction were of the order
of 4.5 mgd. This was met from the Meghadrigedda, and Raiwada schemes of Andhra
Pradesh State Government.
Operational water requirements 70 mgd of the steel plant are being met
ftom the Yeleru water supply scheme provided by the A.P. State Government. This
involved construction of a storage reservoir at Yeleswaram and a 153 Kms. long linked
canal to the plant site apart from the Kanithi Balancing Reservoir.
Product Mix:
The product mix of
VIZAG Steel Plant
compnses
. Wire Rods
. Bars
. Angles
. Channels
. Beams
. Rounds
. Billets
The Plant also produces Pig Iron, Granulated Slag and Coal Chemicals. The rolled
products find extensive usage in the Construction, Inftastructure, Railways, Power, Oil,
defense, and Transport and Ship Building sectors. Bars and Rods are used mainly for re-
inforced concrete work for housing, construction of dams, buildings & factories,
manufacture of agricultural implements, fabrication of light engineering components. The
Wire Rods are used in Wire Drawing industry for electrodes, transmission lines and weld
ability requirements. The structurals find application in engineering, house building,
agricultural implements, machinery, transmission towers, etc.
BRIEF ON STEEL MELTING SHOP OF VSP
In line with international levels of operation, the levels of steel production
can be considerably higher than that what was envisaged in the revised
DPR. Each converter with a volume of 133M3 is capable of producing 150 tons of liquid
steel per heat and considering 10,000 heats annually per operating converter, a liquid steel
achievable ftom one operating converter. Thus with the installation of
third converter in SMS the shop has the potential to produce about 3.0MT of liquid steel.
Accordingly, it is proposed to install one more converter and two additional bloom casters
in SMS-l, within the area provided for the future expansion. As a result, SMS-2 need not be
installed. To achieve the production of3.0 MT per year the following is a must:
~ Silicon content of hot metal should not exceed 1%
~ Lime used as flux should have 90-92 %(CaO + MgO) and Si02 content
should not exceed 2.5%. This may necessitate import of high-grade limestone.
~ Converter lining life should be 300 heats, and the relining time should not
exceed 5 days.
~ The blowing time should not be more than 18 minutes and the gas
cleaning system shall be adequate to meet this requirement.
~ Each bloom caster is required to cast 10 heats in sequence. The machine
availability may have to be
increased to 310 days per year.
~ The capacity of cranes, transfer cars
etc. marginally increased to handle 150 tons
per heat.
FACILITIES:
The major facilities are as follows:
3.0 MT Stage
1. Production (T lye)
(a) Liquid steel (b)
Cast blooms (1) 250x320 MM (2)
250x250 MM
3,000,000
1,915,000
905,0002. Facilities
(a) Hot metal mixers 2x1300T
(b) L-D Converters 2x1333
(c) Continuous casting machines 3x4-strand
2x 1300-7 torpedo
cars of 300T cap
3x133M3
6x4 -strand
REFRACTORIES FOR SMS:
~ FOR CONVERTER LINING: Permanent lining is by chrome magnesite bricks.
Working lining is by pitch -bonded magnesia enriched dolomite bricks.
Magnesite blocks line tap hole. Lining life is 300 heats.
~ High alumina bricks line steel teeming ladles as working lining and medium
heat duty fireclay bricks as back up. Life is 15-20 heats. ~ Mixer lining is by high
duty magnesite bricks, and back-up lining
is by mica insulation bricks. Alumino-silicate bricks line Root. Upto 1.0 Mt of HIM can be held with this lining over a year.
~ High grog bricks line hot metal ladle, and medium heat duty bricks
are used as back-up lining. Life is 500 heats.
~ For slide gate refTactories high alumina based material is used.
~
~
Fire clay and high grog bricks line Tundishes and slag boxes. Stopper rods
for tundishes are corundum graphite mono-block stopper rods, Al203
graphite nozzles. Submerged nozzle is
corundum graphite; lining life of tundishes is 10 heats for working lining.
LAYOUT:
The LD Converter building 36m towards north end and a new scrap aisle is provide
adjacent to the charging aisle. The ladle preparation bay is extended by the north end to
facility installation of new ladle preparation bay is extended by the north end to facilitate
installation of new ladle preparation facilities. The continuous casting department is
extended by 102m towards north end for relocation of CCM-4 and housing the 5th and 6th
bloom casters.
CONVERTERS:
The tap-to-tap cycle time is
Timing in min.
. Charging of scrap 3
. Charging of hot metal 4
. Oxygen blowing18
. Intermediate slag off 3
.Sampling, temperature recording etc.
5
. Steel tapping 6
. Draining of slag 2
. Preparation of converter 3
. Unforeseen days 6
Total: 50
Provision is kept for production of 59 heats per day.
SAILENT FEATURES OF THE CONVERTERS:
· Converter capacity, tons
· Effective volume of converter M3 · Converter specific volume, M3 rr ·
Mouth diameter inside lining, nun
150 145
0.95 2700
· Weight of converter lining including bottom lining,tons 455
· Thickness of working lining, mm 780
· Thickness of permanent lining, mm 230
· Weight ofline shell with trunnion ring and bottom, tons 849
· Weight of lined bottom, tons 60
· Speed of converter tilting, rpm: Max. 1.0
· Min. 0.1
· Lance movement speed, mtslsec: nominal 0.88
· Minimum 0.2
· Lance travel, mm 15000
· Oxygen working pressure 15 KSCG
· Water working pressure 12 KSCG
Suppressed combustion type gas collection, cooling and cleaning system is provided. This
system comprises of tube-bar-tube type skirt, gas cooling hood, closed loop type gas
cooling arrangement with fin-fan cooler, gas duct, ill fan, change over valve, flare satack,
gas holder, electrostatic precipitator, booster fan etc. the gas is being recovered and when
the gas composition is acceptable.
AUTIOMATION AND CONTROL
CONVERTER CONTROL SYSTEM:
Following level hierarchical system is provided: level-l consists of
process control computer system for overall shop management, co-ordination, and data
acquisition and monitoring. Level-2: Blowing: micro computer system for on line dynamic
end point control using sub lance and set point control and Level 3 :Distributed control
systems for control and monitoring of the process parameters, flux and Ferro alloys
charging control, main and sub lance position control etc. This works in conjunction with
electric controls including thyristor
converters and programmable logic controller for sequential and safe operation of process
equipment.
SLAG YARD:
The estimated slag arising is about 2000 kg per ton of cast bloom and one slag pot
of 16M3_18M3 is adequate for one heat. The filled slag pot fTom the converter is
transported to slag yard by self propelled slag transfer car. Two 100+20 T EOT cranes, lime
spraying unit, 10T steel ball, slag dump car etc., are
provided. Pits are provided for dumping, cooling and crushing: Operation of dump car
provided with tilting mechanism is controlled fTom a control post. There are four lime-
spraying points. After cooling, the slag cakes are broken by 10T steel ball by magnet crane.
The steel jams are used as plant return scrap. Broken slags are removed fTom pit by shovel,
pay loader and loaded into dumpers for disposal by road. The total area required for slag
dumping is about 9800 sq.m. In
the slag yard of about 8280 sq.m. is available. Therefore, an additional area of about 1500
sq.m. is provided by extension of slag yard 96 M toward end.. SCRAP PROCESSING AND
STORSGE YARDS:
Plant returns scrap and purchased are stored here. There are two yards. In yard
nO.1 about 38,000 T/yr. Of steel scrap is cut to require and has two 1ST magnet cranes. In
scrap yard no.2 about 60,000 T/yr. Of scrap is processed. This yard has four 1ST magnet
cranes. The sized purchased scrap is received by rail. This yard can store about 19 days
stock. Oxy-acetylene torches and 02 lancing do cutting of scrap. An alligator type scrap-
cutting shear is provided in each yard for preparing scrap to be added during argon rinsing.
Self-loading and unloading trucks will be used for transport of scrap to SMS.
SKULL BREAKER:
About 52,000 T of steel and iron-scrap is processed here. A 20 t overhead crane
with detachable magnet is used for dropping a 10 T steel ball to break the ladle skull and
other pieces. A 50/20 T crane with detachable magnet is used for lading and unloading of
wagons and for supplying and removing scrap fTom the crushing pit. Oxy-acetylene torches
do cutting.
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