A Report on Industrial Visit

A REPORT ON INDUSTRIAL VISIT

TO

VIZAG STEEL PLANT

SUBMITTED TO:

G. HARA GOPAL

PROFESSOR

CBIT

SUBMITTED BY:

SONI SRIDHAR

BE ¾ PROD

02097052

ABSTRACT:

1. INTRODUCTION:

Visakhapatnam Steel Plant, popularly known as Vizag Steel Plant is one of the major

steel producers in India. Vizag Steel Plant has been conferred Navratna status on 17

November 2010. Founded in 1971, the company focuses on producing value-added steel,

with 214,000 tonnes produced in August 2010, out of 252,000 tonnes total of salable steel

produced. It is the only integrated steel plant in the country to be certified for ISO

9001:2000, ISO 14001:2004 and OSHAS 18001:1999

2. HISTORY:

On 17 April 1970, the then prime minister of India, Late Mrs. Indira Gandhi announced

the government's decision in the Parliament to establish a steel plant at Visakhapatnam.

The activities kicked off by appointing site selection committee in June 1970 and

subsequently the committee‘s report was approved for site. On 20 January 1971 she laid

the foundation stone. Consultants were appointed in February 1971, and feasibility

reports were submitted in 1972. The first block of land was taken over on 7 April 1974.

M/s M.N. Dastur & Co was appointed as the consultant for preparing the detailed Project

report in April 1975 and in October 1977 they have submitted the report for 3.4  mtpa of

liquid steel. With the offer for assistance from government of erstwhile USSR, a revised

project concept was evolved. Detailed Project Report for a plant capacity of 3.4 Mtpa was

prepared by M/s M.N. Dastur & Co in November 1980. In February 1981 the contract

was signed with USSR for preparation of working drawings for coke ovens, Blast

Furnace and sinter plant. The blast furnace foundation was laid with first mass concreting

in the project in January 1982. The construction of township also started.

A new company Rashtriya lspat Nigam Limited (RINL) was formed on 18 February

1982. Visakhapatnam Steel Plant was separated from SAIL and RINL was made the

corporate entity of Visakhapatnam Steel Plant in April 1982.

Vizag Steel Plant is the only Indian shore-based steel plant, and it has massive land, up to

19,000 acres (7,700 ha), and is poised to become up to 20 MT in a single campus and

turnover in 2009-2010 was 10,600 Crores. Recently it has gone for expansion from

3.1 MT to 6.3 MT with an investement of 9000 crores.

3. INFRASTRUCTURE:

This section consists of all the infrastructure facilities seen during the visit at Vizag Steel

Plant.

3.1 Coke Ovens & Coal Chemical Plant

Coal is converted into coke by heating the prepared coal blend charge in the coke ovens

in the absence of air at a temperature of 1000oC-1050oC for a period of 16/18 hours. The

volatile matter of coal liberated during carbonization is collected in gas collecting mains

in the form of raw coke oven gas passing through stand pipes and direct contact cooling

with ammonia liquor spray. The gas cooled from 800oC to 80oC is drawn to Coal

Chemical Plant by Exhauster. The residual coke is pushed out of the oven by pusher car

through a guide into coke bucket. The red-hot coke is taken to coke dry cooling plant for

cooling.

The main by product in the process of coke making is crude coke oven gas and this has

lot of valuable chemicals. Coal Chemical Plant recovers Ammonia (NH3), Tar and

Benzol from CO-Gas. The primary By-products from Crude CO Gas are Ammonium

Sulphate (NH4)2 SO4, Crude Tar, Crude Benzol and cleaned coke oven gas. The cooled

coke from CDCP (Coke Dry Cooling Plant) is separated into 3 fractions, BF Coke i.e.

+25-70 mm which is sent to Blast Furnaces, Coke Breeze i.e. +0-15 mm which is sent to

Sinter making and nut coke i.e., +15-25 mm, which is also used in the Blast Furnaces.

Facilities

There are 4 batteries, each having 67 ovens.

The volumetric capacity of each oven is 41.6 m3.

Dry Coal charge /Oven is 32 t

Salient Features

      Largest and technologically unique Coke Oven Batteries in the country at

the time of commissioning.

        7 metre tall coke ovens batteries.

        Selective crushing of coal to improve the coke quality.

        100% Dry Quenching of coke using Nitrogen gas.

        Power generation, from the waste heat recovered, at BPTS (Back

Pressure Turbine Station).

Capacity

Production capacity – 2.635 Mt of Gross coke per annum (2.261 Mt of BF Coke per

annum)

3.2 Sinter Plant

Sintering is agglomeration of fine mineral particles into a porous mass by incipient fusion

caused by heat produced by combustion within the mass itself. Iron ore fines, coke

breeze, limestone and dolomite along with recycled metallurgical wastes are converted

into agglomerated mass at the Sinter Plant, which forms 70-80% of iron bearing charge in

the Blast Furnace. The vertical speed of sintering depends on the suction that is created

under the grate more the suction higher will be the vertical speed of sintering and more

the productivity. At VSP two exhausters are provided for each machine to create a

suction of 1500 mm water column under the grate. Each exhauster is driven by a 5.6 MW

motor capable of rotation the fan at 1000 rpm with an output of 15,000 m3/min

Facilities

Two Sintering machines of Dwight Lloyd type having 312 M2 total grate area each.

Salient Features

      On ground blending of sinter base mix.

Capacity

Production Capacity - 5.256 MT of Sinter per annum.

3.3 Blast Furnace

Iron is made in the Blast Furnaces by smelting iron bearing materials with the help of

coke and air. The solid charge materials like sinter, sized iron ore, etc. are charged in the

vertical shaft of the Blast Furnace at top and hot air blast is blown through the tuyeres

located at the bottom. The oxygen from the hot air combines with the carbon of the coke

and generates heat and carbon monoxide. The gases while ascending upwards react with

the charge. Eventually the charge melts and hot metal and slag are produced and tapped

out. The cooled gas is also used as fuel in the plant. The Paul-wurth, bell loss top system

is installed for furnace charging.

There are four hot blast stoves for each furnace with a total heating surface of 224,000

m2. High temperature zone is lined with silica and mullite corundum refractories, medium

temperature zone, with kaoline refractories and low temperature zone with fire clay

refractories. Its novel circular cast house with four tap holes ensures continuous tapping

of hot metal.

Facilities

Two Blast furnaces of 3200 cum. useful volume each.

Salient Features

        Conveyorised charging of Blast Furnaces

        Paul-Wurth “Bell-less” top charging system for Blast Furnace.

        On-line correction of coke moisture and batch weights.

        Circular cast house with four tap holes and no slag notch.

        Cast house slag granulation plant.

        Tuyere leakage detection system

        Gas Expansion turbines for power generation by utilizing the blast

furnace gas top pressure

        Automation with Programmable Logic Controllers (PLC).

        A circular cast house with four tapholes and no slag notch.

Capacity

Production Capacity – 3.4 MT of Hot Metal per annum.

3.4 Steel Melt Shop & Continuous Casting

Steel is made in steel melting shop in the refractory lined vessels called LD Converters

by blowing oxygen through the hot metal bath. While iron making is a reduction process,

steel making is an oxidation process. The oxygen reacts with the carbon in the hot metal

and this reaction releases large quantities of gas rich in carbon monoxide along with huge

amount of dust. The gases released from the converter are collected, cooled, cleaned and

recovered for use as fuel in the steel 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.

Facilities

Three LD converters of 133 cum. volume each

6 nos. of 4-Strand Continuous Bloom Casting machines.

Salient Features

        100% Continuous casting of steel

        Converters gas cooling, cleaning and recovery systems

        Use of Sublance and computerisation of the converter process

Capacity

Production Capacity – 3.0 MT of Liquid Steel per annum

          – 2.820 MT of CC Blooms per annum

3.5 Light & Medium Merchant Mill

Blooms from Continuous Casting Division are rolled into billets, some of which are sold

and rest are sent to WRM. The continuous multi-line mill comprises 8 stand double

strand roughing train, 2 Nos., 4 Stand Single strand finishing trains. Loopers are provided

in between the finishing stands for tension free rolling in order to obtain good surface

quality and tolerances. Housings are of closed top type. Roll necks are mounted in anti

friction bearings.

Facilities

7 Strand Break-Down Mill

8 Strand Roughing Mill

5 Strand intermediate Mill (2 Strand rolling)

2*4 Strand Finishing Mill (Single Strand rolling)

6 nos. of 4-Strand Continuous Bloom Casting machines.

Salient Features

        Evaporating cooling systems in Rolling Mill furnaces.

        Computerization in Rolling Mill

        Tempcore cooling process facilitating high strength with good

bendability and weldability.

Capacity

A Mill of 0.710 MT per annum production capacity.

3.6 Wire Rod Mill

The Wire Rod Mill of VSP is high speed 4 strand No-Twist continuous mill designed to

produce 8,50,000 T of wire rod coils. The mill is designed to produce plain wire rods

from 5.5 mm to 12.7 mm dia and Rebar in 8mm, 10mm and 12mm diameter in coil form.

However sizes up to 14mm are being rolled presently. The mill is constructed at an

elevated level of +5350 mm. Rolled billets of 125 mm x 125 mm square cross section,

length ranging from 9.8 m to 10.4 m and weighing approx 1250 kgs are used as input

material. The mill is designed to roll steel stock of 0.9% max. Carbon content.

Facilities

7 Strand Roughing Mill (4 Strand rolling)

6 Strand Intermediate Mill (4 Strand rolling)

4*2 Strand Pre-finishing Mill (Single Strand rolling)

4*10 Strand Finishing Mill (Single Strand rolling)

Salient Features

        Evaporating cooling systems in Rolling Mill furnaces.

        Computerization in Rolling Mill

        Controlled cooling of Wire Rods, by ‘Stelmore’ process giving high

strength and good ductility.

Capacity

A Mill of 0.85 MT per annum production capacity.

3.7 Medium Merchant & Structural Mill

The Medium Merchant and Structural Mill (MMSM) is one of the modern rolling mills of

Visakhapatnam Steel Plant. It is the third and last rolling mill as per the rationalized

concept. This is a single strand continuous mill having production capacity of 8,50,000

T/year. The important feature of this mill is that Universal beams (both parallel and wide

flange) have been rolled first time in India using Universal stands. Parallel flange beams

have advantage over conventional beams as per the same weight the section is stronger

and stiffer due to greater moment of inertia and higher radius of gyration.

Facilities

8 Strand Roughing Mill

6 Strand Intermediate Mill

6 Strand Finishing Mill

Salient Features

        Evaporating cooling systems in Rolling Mill furnaces.

        Sophisticated, High speed rolling mills with computerized controls

Capacity

Walking Beam Furnace – 1 lighting up – 22.11.92

Walking Beam Furnace – 2 lighting up – 24.12.91

Mill inauguration – 28.03.92

4. CONCLUSION