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.

Section through the BOF vessel during oxygen blowing.