Showing posts with label BF. Show all posts
Showing posts with label BF. Show all posts

May 15, 2012

Biggest Blast Furnace BF-3 Goes on Stream at Rashtriya Ispat Nigam Limited (RINL) - Vishakhapatnam Steel Plant (VSP)


The blowing-in process of newly built third Blast Furnace (BF–3) which was commenced on Wednesday (24th April 2012) went through successfully with first tapping of Hot Metal from Blast Furnace (BF–3) took place at 17.06 hrs IST. With this the 3800 cubic meter capacity Blast Furnace – 3 at RINL (Rashtriya Ispat Nigam Limited) / VSP (VishakhapatnamSteel Plant) goes on stream adding about 4 per cent capacity increase in the country. It was built as a part of the expansion project to take the capacity of the Vishakhapatnam Steel Plant (VSP or RINL) from the present 3 million tonnes to 6.3 million tonnes. The cost of the blast furnace along with the turbo blower, water system and auxiliary systems is estimated at Rs 3,800 crore.
Blowing-in of the newly built third Blast Furnace (BF-3) was carried out by employees along with CMD, RINL (Rashtriya Ispat Nigam Limited) on 24th April 2012. Sri.A.P. Choudhury, CMD, RINL chaired the long cherished dream of commissioning of biggest blast furnace by participating with employees in tapping process and congratulated one and all for this historic moment. Sri. Beni Prasad Verma, Honourable Union Minister of Steel, Sri. D.R.S. Choudhury, Secretary Steel congratulated the RNIL collective for the successful commissioning and production from new blast furnace (BF – 3).
Sri. S. Machendra Nathan, AS and FA who is in RINL complimented the team by witnessing the tapping process. Dr. Dalip Singh, Joint Secretary, Steel and the Independent Directors of the Company complimented the RINL collective. Directors of the company along with several senior officers witnessed this most memorable moment of first tapping.   
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August 31, 2011

Job Opportunity (Vacancy) for Mechanical, Refractory, Metallurgical Engineers | Senior Executive (Manager) - Blast Furnace Operation at Nagpur (India)



Senior Executive / Manager - Blast Furnace Operation
Company Name
F S Management India Pvt. Ltd., hiring for their client who are a leading Refractories Manufacturing Company based in Nagpur, India.
Position
Senior Executive / Manager - Blast Furnace Operation (No. of vacancy – 1)
About the Company
The employer is a leading manufacturing company of refractories, ceramics, and bricks.
About the Job
As an operation in charge, the incumbent will be responsible for smooth operation of Blast Furnace as well as Blast Furnace related equipments, Refractory Deskulling (Braking) and Refractory Lining of Mini Blast Furnace, Tap hole maintenance, operation of Cast House.
Location
Nagpur, Maharashtra (India).
Job Type
Regular.
Functions
Operational / Engineering / Maintenance.
Industry
Refractory / Steel.
Desired Candidate Profile
B.E / B.Tech / Diploma (Mechanical Engineering / Ceramic (Refractory) Engineering / Metallurgical Engineering) with 5 - 10 years of exposure to the operation and refractories of Blast Furnace and Refractory Braking (furnace deskulling) and refractory lining etc.  
Salary Package 
A beautiful growth package will be offered.​

Contact Details
Priti Srivastava / Varsha Das
F S Management India Pvt Ltd
FS House, Marui Vihar, Mahoba Bazar
G E Road, Raipur 07712575542
RAIPUR,Chhattisgarh,India

August 29, 2009

Blast Furnace Trough Materials (Trough Mix)


The flow rate of molten metal and slag through the trough system increase many times in case of larger blast furnaces. To get good campaign life special attention must be given to both refractory lining and design i.e. trough geometry and cooling system. The trough design is based on fluid flow characteristics along with thermo-chemical reactions. The important parameters of the geometry would be - length, width, depth at drainage point, distance between iron and slag over-flow, skimmer opening dimensions, and side-wall angle. Each of the above parameters affects the campaign life of the furnace trough if not designed properly. Cooling helps to bring down the hot face temperature, and thus the wear by way of chemical attack, infiltration and thermal stresses.
Development of sophisticated materials and innovative installation and repair techniques now make it possible to hold hot metal in today’s deep pooling type iron troughs for a week or more without draining for maintenance. In this area the traditional graphitic high alumina ramming masses used in the past have been replaced by high quality, low moisture, metal or organic fiber containing  castables with  Al2O3 - SiC - C as the standard refractory base material (dry ramming masses / gunning compound / ULCC) for troughs. The important physical properties for this material are - thermal expansion, hot strength and thermal conductivity. The following shows the role of different constituents of trough mix (material).
Table: Role of different components in the
Blast Furnace Trough Mix (Refractory)
Material
Role
Alumina components
=> Volume stability
=> Wear resistance
Silicon Carbide (SiC)
=> Wear resistance
=> Oxidation resistance
=> Slag penetration resistance
Carbon
=> Spalling resistance
=> Slag penetration resistance
Anti-oxidants
=> Oxidation resistance
=> Hot MOR
Resin
=> Hot MOR
=> Binding strength
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July 27, 2009

Blast Furnace (BF) - Refractory Lining Pattern

Refractory Technology: Different temperature zones of a Blast Furnace image Fig: Blast Furnace Temperature Zones

Refractory Technology: Blast Furnace image
Fig: Typical areas of a Blast Furnace
Blast Furnace - An Introduction
Blast Furnace is the focus of any integrated steel plant. Blast furnace is used to reduce the iron ore to iron. The charge, which consists of iron ore, coke and limestone etc. in the form of lumps and different ratios, is fed from the top. Air heated in the blast furnace stoves, is applied from the bottom of the furnace. The hot blast comes in contact with the descending charge in furnace and the iron ore gets reduced to iron due to reducing conditions on account of CO2 and CO in the furnace. CO provides further heat and a very high temperature is developed because of which the iron gets melted which, along with the slag is collected in the hearth from where these are tapped separately from different tap holes.
Ironmaking technology in general made great strides particularly, during the past few decades and as a result of which many alternative ironmaking processes such as Finmet, Fastmet, Hismelt, Romelt, COREX®, and FINEX® etc. have emerged. Nevertheless, the classical Blast Furnace, which has been around the longest, continues to be the dominant method of ironmaking till now. Improvements in burden quality, burden distribution, casting technology, and computer assisted supervision were realized throughout the world. To a great extent these operational improvements made it possible to install very sophisticated refractory lining systems in blast furnaces. The application condition of different sections of a blast furnace is different due to the very nature of its geometry and also pyrometallurgical process occurring at different stages (see adjacent Blast Furnace figures). Therefore, the Blast Furnace Bottom, Hearth, Taphole, Tuyeres, Bosh, Belly, Stack, Cast house, Blast Furnace Stoves all require different quality of refractories depending on the respective application conditions.
Selection of appropriate refractory combination depends on in-depth knowledge of ironmaking system and the physical, mechanical and chemical properties of the proposed refractories. An improper understanding of the above factors often leads to a refractory failure which, subsequently, becomes a complex problem to solve. Refractory linings whether it is of a Blast Furnace or any other furnace, usually fail due to any number or combination of such factors. For the convenience of understanding, here we will discuss the types of refractory lining required in a blast furnace area wise as well as the trend in the refractory lining pattern that has been observed during the last few years.
Furnace RefractoriesRefractory Technology: Blast Furnace refractory lining pattern graphics
Fig: Conventional and New Refractory Lining along with Wear Mechanism
Now-a-days the campaign life of Blast Furnace is measured in terms of 10 - 15 yrs rather than 4 - 5 yrs while on the other hand, the trend is to replace smaller Blast Furnaces with large capacity Blast Furnaces, which are being subjected to even more stringent operating conditions. To achieve these goals, it is necessary to have a good combination of high grade refractories combined with highly efficient cooling systems and tight control on furnace operation to ensure high productivity without excessive wall working and with minimization of massive “slips” in the blast furnace which can cause excessive premature damage to the refractory linings. It is known that the bottom and a part of the hearth are corroded mainly by pig iron, slag and alkalies. Refractory bricks in these areas are subjected to high load and temperature. So it requires a refractory lining which should have high strength, lower creep in compression value and higher RUL and PCE values. Many furnaces still use low iron, dense 42-62% Alumina, Mullite refractory bricks, conventional Carbon blocks etc. in the bottom and lower hearth while the present trend is to replace it with super micro-pore Graphite bricks.
Research and data shows that Blast Furnace hearth life mainly depends on the following factors:
1. Operational Factors such as,
(a) High productivity leading to High heat loads
    (b) High fluid velocity causing more erosion
    (c) High coal injection means lower permeability
None of the above factors is under the control of furnace operator and hence, the only solution for this can be a robust refractory lining.
2. Refractory Lining System Design The entire refractory lining is also subjected to thermal stress which also plays a dominant role especially when the design is inadequate. The refractory lining system or design must take care of the following things -
(a) Optimize thermal resistance
(b) Provide expansion relief
(c) Prevent cracking
(d) Eliminate built-in barriers.
3. Refractory Properties
(a) High thermal conductivity
(b) Alkali resistance
(c) Low permeability
(d) Low thermal expansion
(e) Low elasticity.
The recent development of micro-porous carbon bricks and improvement in the quality of semi-graphite and graphite bricks has led to higher infiltration resistance to iron and slags, and thermal conductivity. The problem of brittle layer formation around 800OC isotherm by alkali condensation and thermal stresses have been addressed to by using smaller blocks, optimum expansion allowances etc. The carbon refractories are covered by fireclay or mullite bricks to protect it against oxidation. The design of this ‘Ceramic Cup’ is important, as the isotherms are altered depending on the quality and thickness of the cup material.
The stack bricks are particularly; exposed to high abrasion and erosion by charge material from top as well as high velocity fume and dust particles going out due to high blast pressure in a CO environment. Therefore, the application condition demands refractory materials which should have high strength, low permeability, high abrasion resistance and resistance to CO disintegration. Superduty fireclay refractory brick or dense alumina brick having Al2O3 around 39 - 42% can impart these characteristics required for stack application. The tuyere and bosh are attacked by temperature change, abrasion and alkalies; and the belly and lower shaft by thermal shock, abrasion and carbon monoxide attack etc. In the critical areas of the furnace, i.e. tuyere, bosh, belly and lower stack, silicon carbide, SiC-Si3N4 and corundum refractories have replaced carbon and 62% Al2O3 or Mullite bricks – taking advantage of the high thermal conductivity of SiC in combination with the stave coolers. However due to the problem of water leakage around taphole and tuyere area many blast furnaces are lined with high alumina or Alumina-Chrome corundum refractories.
Hot Blast Stove Refractories
The hot blast system, incorporating either three or four hot blast stoves per blast furnace, is the other major refractory installation in the blast furnace complex. With today’s large blast furnaces, the main trend in hot-blast stoves is toward high temperature and pressure ventilation with dome temperature around 1550OC, blast temperatures of 1250 - 1400OC, and furnace pressures of 3 - 5 kg/cm2. Therefore, selection of refractories for hot blast stoves depends primarily on their creep resistance properties, bulk density, specific heat, thermal shock resistance, cold crushing strength, thermal expansion and dimensional accuracy. Blast furnace stoves are generally designed by high alumina bricks and checkers. Silica bricks have been introduced in high temperature stoves operating over 1300OC and where the temperature is never allowed to drop below 600OC as silica bricks display poor thermal shock resistance at such low temperatures. Alternatively silica checker bricks can be used can be used in high temperature zone, high alumina bricks in the middle temperature range and hard fired fireclay bricks and other high strength bricks at the bottom checker level.
Table: Blast Furnace Refractories
Area
Present
Trend
Stack
39-42% Al2O3
Super-duty fireclay
Belly
39-42% Al2O3
Corundum, SiC-Si3N4
Bosh
62% Al2O3, Mullite
SiC-Si3N4
Tuyere
62% Al2O3, Mullite
SiC self-bonded, Al-Chrome (Corundum)
Lower Hearth
42-62% Al2O3, Mullite, Conventional Carbon block
Carbon/Graphite block with super micro-pores
Taphole
Fireclay tar bonded, High Alumina / SiC tar bonded
Fireclay tar bonded, High Alumina / SiC tar bonded
Main Trough
Pitch / water bonded, Clay / Grog / Tar bonded ramming masses, Castables
Ultra low cement castables, SiC / Alumina mixes, Gunning repairing technique
Tilting Spout
High alumina / SiC ramming masses / Low Cement Castables
High alumina / SiC / Carbon / ULCC
Hot Blast Stove
42-82% Al2O
70-82% Al2O3, 91% SiO2 checker bricks

Recent Articles –
Blast Furnace Trough Mix (Refractories)

July 19, 2009

Blast Furnace (BF) - Design and Ironmaking

Refractory Technology: Blast Furnace Cross Section imageRefractory Technology: Temperature and other Recorders of a Blast FurnaceRefractory Technology: Blast Furnace assembliesRefractory Technology: Conveyor and Skew Charging systems of a Blast Furnace imageBlast Furnace Stoves and Gas Cleaning equipment images

Amongst all the ironmaking processes, the Blast Furnace technology, which has been around the longest, still holds the dominant position. Many of the innovative ironmaking technologies that have emerged in the last few years will definitely complement the blast furnace in the coming years; but it is accepted even after these technologies are fully established, the blast furnace process will continue to be the principal ironmaking technology for iron makers. This is because though although the blast furnace process has a long history; it has remained up-to-date and competitive owing to the continuous and several innovative developments in its design and refractory lining pattern etc. that have taken place since its inception. The following table shows the history of Blast Furnace lining life:

Date

Daily production NTHM/day

Time before Reline/Repair in days(years)

Tons per lining NTHM

1600s

1

300 (0.8)

300

1700s

5

300 (0.8)

1500

1800s

30

300 (0.8)

9000

1910s

350

570 (1.5)

2,00000

1920s

500

1500 (4.1)

7,50,000

1940s

1600

1500 (4.1)

24,00000

1960s

2500

1500 (4.1)

37,50,000

1980s and 1990s

3600

2800 (7.7)

100,00000

Refractory Technology graphicsBlast Furnace - Bell Less Top Charging imageRefractory Technology: Blast Furnace Bell Less Top Charging imageBlast Furnace - Bell Less Top Charging system image

During this period and till today, Iron & Steel industry and the Refractory industry have been working in tandem with each other to generate a win-win situation and ensure a steady growth for these industries. The equipment and systems of modern Blast Furnace Technology are designed for the harsh environment in the ironmaking operations, meeting the demands of reliable operation and minimal maintenance requirements. Hot metal production rates of 8000 - 10000 tpd, fuel rates of around 450 - 470 kg/thm (270/275 kg coke plus 175/225 kg coal), productivity of 2.5 - 3.0 t/m3/d (based on inner volume), and furnace availability ranging between 95 - 98% are the results of improved process control, better understanding of the process and stability of operations. Today the strategy of the iron-makers is to extend the campaign life of Blast Furnace as much as possible so that the total relining is required at least after 14 - 15 yrs of operation. However partial relining or repairing is required to enable safe operation side-by-side maintaining the quality of the product. To perform Blast Furnace rebuilds, relining and modernizations, extremely tight timeframes are demanded. This is achieved in close co-operation with local erection companies and means substantial cost benefits to the client. Moreover, for the last few years the trend is to replace smaller Blast Furnaces with large capacity Blast Furnaces, which are being subjected to stringent operating conditions like - high pressures at very high temperature of even more than 2000OC where sometimes the pressure goes beyond 5kg/cm2 on the Furnace Bottom. All these developments have ensured that the “Old” blast furnace remains “Young” and also the process of ironmaking in classical blast furnaces will continue to be the dominant method globally in the years ahead, as indeed has been the case in the past.

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