BLAST FURNACE

Introduction: The main function of Blast Furnace in steel industry is to produce pig iron for steel making by smelting iron ore of different grades with coke, flux and a blast of air. At present in DSP there are four Blast Furnaces of which the details are as following:-
Furnace No. Name Useful Volume Capacity Blast Temperature
1. Kasturba 1323 cu m. 1250 T/Day 11000C
2. Kamala 1400 cu m. 1870 T/Day 11000C
3. Sharada 1400 cu m. 1820 T/Day 11000C
4. Durga 1800 cu m. 2340 T/Day 12000C

The raw materials used are:

1. Coke: Hard porous coke, which serves as a source of heat and a reducing agent
2. Flux(limestone & dolomite): Flux is used to combine with the gangue material of the ore and the ash of the coke to form a fusible mass known as slag which is used in the cement production.
3. Blast of Air: A hot blast of air is given to the mass to supply necessary oxygen for combustion.

SOURCE OF RAW MATERIALS

• Iron ore - Bolani, MMTC
• Limestone - Birmitrapur, Birla
• Manganese ore - Bolani, MMTC, Barabil

PROCESS DESCRIPTION
There is a storage house for the various raw materials used for the charging the blast furnace. Iron ore, coke, flux, Manganese ore, quartzite etc are stored in the bunkers. These bunkers are fed by conveyers and also by wagons. Scale cars running below the bunkers on track charged the required amount of raw materials into the skips and skips charge them into the blast furnace. The scale car is not being used in blast furnace II.
The raw materials are charged into the furnace from the top in the required proportion and then preheated air is blown in through a number of symmetrically placed openings called tueyers. The main air pipe is known as Bustle pipe. The reducing gases rise up through the descending raw materials. The descending raw materials travelling through the various temperature zones are heated up, prepared and gets smelted. The liquid iron and the liquid slag formed trickle and accumulate in the hearth, which is the bottom most part of the blast furnace. The slag separates and floats above the liquid metal, as it is lighter than the hot metal. The descending raw materials takes 10-12 hours to descend and gets melted, whereas the gases take only a few seconds to ascend. The slag produced is separated from the molten metal with the help of an obstruction, which is known as skimmer and is boat shaped, is poured into ladles, which are then sold or sent to Durgapur Cement Works for cement production.

TYPICAL ANALYSIS OF THE BLAST FURNACE PRODUCTS
Hot Metal: Si=1.67% S=0.45% Mn=0.46% Slag: SiO2=32.9% Al2O3=23.5% MgO=4.2% CaO=35.9% Blast Furnace Gas: CO2=14.4% O2=0.2% CO=25.8% H2=2.8%

SINTER PLANT

Sinter is a hard porous produced by incipient fusion combustion developed within the mass itself. It is agglomerated from the iron ore fines, limestone and dolomite fines, flue dust and coke fines.
Sinter plant plays a vital role in the modern steel making industries. It has following advantages:

1. It has sufficient strength, porous giving more surface area for reaction, partial (incipient) fusion leaves iron ores.
2. Utilization of all iron ore fines which have increased due to mechanization of iron ore mining, 40% of iron ore fines is produced during mining.
3. Utilization of all waste materials like coke breeze, mill scale, carbide sludge, lime dust, flue dust.
   

RAW MATERIAL HANDLING COMPLEX

It is the starting point in the steel making process in DSP. RMHC is mainly concerned with the receiving, unloading, storing and processing of all the raw materials viz. iron ore lumps, limestone, dolomite, manganese ore and bauxite. The preparation of sinter mix is also done in RHMC using state of the art automation.
It consists of two plants:-

1. Ore handling plant
2. Coal preparation plant.
   

ORE HANDLING PLANT INVOLVES

• Unloading and storage of ores and fluxes with new wagon tipplers and side oven chargers
• Screening and blending facilities of iron ore lumps
• Flux crushing and screening facilities
• Computerized raw sinter mix preparation
• Stacker cum Reclaimer for handling iron ore lumps and fines, limestone and manganese ore
• Automobile sampling and electronic weighing facilities on conveyer routes
  

COAL PREPARATION PLANT INVOLVES

• Four additional coal storage bed units with new wing trippers for stacking and bucket wheel reclaimer
• For reclaiming bunker blending
• Selective crushing in two stages with pneumatic clarifier
  

DURGAPUR STEEL PLANT

The integrated steel plant, spread over an area of 6.5 sq km, employs a workforce of about of 17 thousand people. The largest industrial complex in West Bengal, Durgapur Steel Plant has introduced the latest state-of the-art technology that would ensure production of better quality of steel at a lower production cost that would enable it to operate as a viable unit. The modernization programme, undertaken with an expenditure of around Rs. 5000 crores, is the biggest such programme for any single unit in the country. It has brought about a complete transformation of the organization. After the completion, of modernization, the plant is envisaged to attain higher levels of annual production: hot metal – 1.92 million tons, liquid steel – 1.876 million tons and saleable steel – 1.586 million tons.
SMS, BOF, Merchant Mill, Wheel and Axle Plants are covered by ISO9002 Quality assurance certificate. With the successful commissioning of the modernized units DSP is all set to produce 2.088 tons of hot metal, 1.802 MT of crude steel and 1.567 MT of saleable steel.

The salient features of DSP are given below:



SHOPS/UNITS: PRINCIPAL PRODUCTS
(Size in mm)
A. BLOOMING MILL Blooms Slabs 190×160,210×160,250×250,356×18
B. BILLET MILL Billet Slabs 100×100,125×125,75×100,140×75,155×75,210×75
C. MERCHANT MILL Round and Thermo mechanically treated bars 12,14,16,18,etc.
D. SECTION MILL Joists Flats Channels Angle 116×100,200×100,150×75,225×100
40,55 thickness of 6-12 mm.
125×65,175×75,150×75,200×75,280×82
150×150,130×130,110×110,100×100
E. SKELP MILL Strip & Skelp 147,181,184,196,205
F. WHEEL & AXLE PLANT Wheel
Wheel sets : For Diesel engines.
: For Railways coaches.

SEMI FINISHED STEEL (Blooms and Billets): 65,70,90,160 to 250 mm.

DSP AT A GLANCE:

A dream child of Dr. B. C. Roy, Durgapur Steel Plant was set up in the late fifties with an initial capacities of one million tons of crude steel per annum. Its standards and norms were determined by the raw material characteristics available then. In the late sixties, the capacity of the plant was enhanced to 1.6 million tons of crude steel per annum and further enhanced to 1.876 million tons.

• Coke ovens: 4 batteries of 78 ovens each.
• Blast Furnace:
  FURNACE NO. NAME USEFUL VOLUME CAPACITY
  1 Kasturba 1323 cu m. 1250 T/Day
  2 Kamala 1400 cu m. 1820 T/Day
  3 Sharada 1400 cu m. 1820 T/Day
  4 Durga 1800 cu m. 2340 T/Day
  
• Steel Melting Shop: 3 × 110 tons BOF converters to produce 1.876 MT of liquid steel.
  
  
• New Lime Calcination Plant: 2 × 300 T per day lime kilns to produce soft burnt lime.
  
  
• Rolling Mills: Primary two strands 42” & 32”, Blooming Mill and a Billet Mill, Section Mill, Merchant Mill, Skelp Mill, Wheel & Axle Plant.
  
  
• Service Units: Central Engineering Maintenance, Foundry, Oxygen Plant, and Power Plant, Electrical Repair Shop, Research and Control Laboratory, and Training Department.
  
  
• Railways Tracks: 180 km.
  
  
• Roadways: 32 km.
  
  

INTRODUCTION

A BRIEF HISTORY OF SAIL:

The Government of India decided in December 1972 to set up a holding company for steel and the associated input Industries under the name of Steel Authority of India Limited (SAIL). To be registered in the Union Territory of Delhi. The company with an investment of Rs. 13,972 crores is the largest industrial enterprise in India. With a turnover of Rs. 16,000 crores a year, SAIL figures in the list of the top Industrial corporations of the world.

SAIL FAMILY:

At present SAIL manages the following Plant Units and subsidiaries:

• Bhilai Steel Plant.

• Bokaro Steel Plant.

• Durgapur Steel Plant.

• Rourkela Steel Plant.

• Alloy Steel Plant, Durgapur.

• Salem Steel Plant.

VERSATILITY OF ITS PRODUCTS:

SAIL is today India’s largest steel producer and the world’s ninth largest. It’s five integrated plants have a total capacity of 11 tons of crude steel. The ASP, SSP and VISL are engaged in the production of special and alloy steel and MEL is the only producer of ferro-alloys.
SAIL produces about 500 grades of mild and special alloy steel which caters the need of several industries like the automobile industries, Ship building, Indian Railways, ONGC, Power Sector, Defense, Construction, etc. The product not only finds market in India but have also found ready acceptance in about 70 countries. Product export to various countries include mild steel Billets, slabs, hot rolled plates, coils, sheets, wheels, etc. In 2001 SAIL plans to achieve an export level of 155 of its products.

ACKNOWLEDGEMENT

We express our sincere thanks and gratitude to the Training Department, D.S.P. for giving us an opportunity to visit the plant and to learn varied aspects of the plant.

We would like to thank all the employees of D.S.P. for their co-operation and giving knowledgeable technical explanation and advices, without which the training would have been meaningless.

We also like to thank Dr. Ananta Kumar Das (Head Of The Department, Chemical Engineering) and all the faculty members for their useful guidance regarding the preparation of project report.

ABHRA DAS
PRANTIK KARMAKAR
SOUDIPTYA KUMAR BASU
Chemical Engineering Department
DIATM, Rajbandh, Durgapur, W. B.

A REPORT ON:
OVERVIEW OF THE PLANT
PREPARED BY:

ABHRA DAS

Process Engineer

Himadri Chemicals & Industries Limited

Mahistikri, Haripal, Hooghly (W.B.)

Prantik Karmakar
Chemical engineer


Soudiptya Kumar Basu
Chemical Engineer
Pursuing M.Tech from NIT.