Download - Alternative Iron making processess
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ALTERNATIVE SR PROCESSESS FOR IRON MAKING: RELEVANCE TO INDIA
V.MOHAN 1011207008Y.S.R. ENGINEERING COLLEGE OFYOGI VEMANA UNIVERSITY
VISHNUMAHANTHY
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FUTURE CHALLENGESRESOURCE DEPLETION
RISING ENERGY DEMAND
ENVIRONMENTAL CARE
TOPICS, IRON MAKERS SHOULD CONSIDER.
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FUTURE RISKSRESOURCE DEPLETION
RISING ENERGY DEMAND
ENVIRONMENTAL CARE
INCREASING RAW MATERIAL COST
INCREASING ENERGY COST
ENFORCED ENVIRONMENTAL
LAWS
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More than 90% of world iron production is through Blast furnace technology route.
Driving forces: Alternative Iron making technologies:
Costly and scarce coking coal: Need to look beyond coking coal.
Possibility to use iron ore fines directly. Environmental considerations. Eliminate pollution-intensive sintering and coke-making
processes. High capital cost
EMERGING SCENARIO IN IRONMAKING
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Possible Solutions
Direct Reduced Iron (DRI)
Reduction of ferrous oxide in solid state. SL/RN, MIDREX, ITmk3 etc.
Smelting Reduction of Iron
COREX, FINEX, Hismelt etc. using non-coking coal. Obviating the need for coke oven batteries and
sinter plants.
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INDIAN Raw Material Flexibility� Iron ore
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Dry fines (-6mm) and slimes (ultra-fines) – used directly
High phosphorus content possible
No blending or agglomeration necessary
Can be pre-heated / pre-reduced to increase process efficiency
� Steel plant wastes
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Dry fine wastes and metallic fines – used directly
E.g. mill-scale, steel-making slag, reverts, coke breeze
� Coal
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Non-coking coals – ground to -3 mm and driedFrom coke breeze (low volatile) high volatile thermal coal (40%)
No blending, briquetting or coking required
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CONVENTIONAL BLAST FURNACE PROCESS
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Characteristics of Blast furnace processSTRENGTHS
High energy efficiency High productivity Long service life
LIMITATIONS Use of high grade raw materials Coke and sinter making processes required Generation of air pollutant such as Sox, Nox, Dioxin
and dust.
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Available Smelting Reduction (SR) Processes SR technologies currently commercially exploited or ready for commercial exploitation.
COREX (Two stage): Operating commercially
FINEX (Two stage): Operating commercially
HISMELT (Single stage):Not being Operating commercially
at present.
• Single stage: Reduction & melting in the same vessel• Two stage : Reduction in one vessel; melting in the 2nd vessel.
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COREX TECHNOLOGY
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COREX: Process Features Developed by Siemens VAI. Commercially most successful among SR technologies. Work is carried out in 2 reactors.
Reduction shaft Melter-gasifier.
Commercial units in operation
Korea : POSCO (COREX C-2000 – Capacity: 0.8 Mtpa)
India : JSW Steel (2 Units) (COREX C-2000)
: Essar Steel ltd (2 units) (COREX C-2000)
South Africa: Mittal-SALDANHA, (COREX C-2000)
China : Baosteel, (COREX C-3000) – Capacity 1.5 mtpa
COREX PROCESS Charge is charged into a
reduction shaft where they are reduced to direct reduced iron (DRI) by a reduction gas moving in counter flow.
Discharge screws convey the DRI from the reduction shaft into the melter –gasifier.
In Melter-gasifier final reduction and melting takes place.
Hot metal and slag tapping are done as in conventional blast furnace practice.
The gas leaving the reduction shaft is cooled and cleaned and is used for a wide range of applications.
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Blast Furnace vs COREX
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Strengths Hot metal quality. Economic benefit . Ecological benefit. non-coking coal can be used. generation of highly valuable export gas.
Limitations Can't use ore fines directly. Restriction on non-coking coal.
VM of carbonaceous material to be maintained at 25% . Net export gas (CV:1800 Kcal/Nm3) to be utilised very
economically, the process becomes un-viable.
COREX: Process Features
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© HIsmelt Corporation 2008
FINEX TECHNOLOGY
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FINEX PROCESS
Siemens VAI and POSCO jointly developed the process. FINEX R&D since 1992. FINEX demo of 600 Kt/y since June 2003. FINEX of 1.5 Mt/y in May 2007 (1st
commercial plant).
Based on the direct use of non-coking coal and fine ore.
Most exciting iron making technology on the market today.
Fine iron ore is preheated and reduced to fine direct reduced iron (DRI) in a three or four stage fluidized bed reactor system.
The fine DRI will be compacted and then charged in the form of hot compacted iron (HCI) into the melter gasifier.
The charged HCI is subsequently reduced to metallic iron and melted.
The generated FINEX export gas is a highly valuable product and can be further used. The hot metal and slag produced in
the melter gasifier is frequently tapped from the hearth as in blast furnace or COREX® operation
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Blast Furnace vs FINEX
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Advantages of FINEX Technology�Flexibility in Raw Materials
Elimination of sintering & coke-making processes. No blending of ore &coal. Use of Low-grade ore &low-ranked coal.
�Easy &Flexible Operation
Independent control of reduction &melting processes. Easy &hassle-free operational control.
�Environmental Friendliness
Far less emission of Sox. Nox & dust.
�Cost Competitiveness Lower cost in both capital investment &operation vs. BF
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FINEX - Advantages
production
pollutants
Blast Furnace FINEX
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④
Specific amount* Relative index
of CO2 emissions per ton of hot metal
② Reuse of FINEX top gas with CO2 removal
④ Reduction of cooling gas use
Note1 Average figure was calculated using estimated amount of CO2 emissions from blast furnaces at fourteen steelworks located in Asia and Europe
130 % Technologies applied to reduce CO2
① Production of hot compacted iron
③ Purverized coal injection
⑤ High pressure operation
106 %World average of blast furnace
at 100% note1
94 %
98 %Dec. 2006
1st Target 91 %2nd Target
FINEX Demo FINEX 1.5 Mt
CO2 emission trends of FINEX
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Hismelt Technology
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The Hismelt Process
Offgas
� Ore & coal are injected into the molten bath.
Raw MaterialsInjection Lances
Hot blast is injected into the top-space
Oxygen EnrichedHot Air Blast
Water cooledpanels
� Metal flows out continuously
ForehearthSlag
Notch
Metal Bath
Smelt Reduction Vessel(SRV)
Slag is batch tapped.
Higher Quality Iron: Compared
to blast furnaces
# Dependant on sulphur input (mainly from the coal). With hot metal de-sulphurisation treatment(known technology) sulphur levels are easily able to be reduced to <0.05%.Low Phosphorus Ore
High Phosphorus Ore
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Typical Analysis Blast Furnace
Carbon 4.5%
4.4 ± 0.15%
Silicon 0.5 ± 0.3% <0.01%
Manganese 0.4 ± 0.2% <0.02%
Phosphorus 0.09 ± 0.02% * 0.02 ± 0.01% **
Sulphur 0.04 ± 0.02% 0.1 ± 0.05% #
Temperature 1430 - 1500°C 1420°C
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1.4
~10-20% loweroperating costs
1.2
1.0
0.8
0.6
0.4
0.2
0.0
Blast Furnace HIsmelt
Rel
ativ
e I
nd
ex
Ore Coal Other
Lower Operating Cost
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Hismelt’s Advantages for India
� Flexibility in Raw Materials� Lower Capital & Operating Costs
� Lower Environmental Impact
� High Quality Iron Product
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Developing markets mainly led by china and India pulling the global steel demand.
Restricting growth factors are: Scarcity of high grade raw materials. Global environment problems and concerns.
Development of innovative alternative iron-making process technologies.
Low grade, low cost resources and to reduce the level of air pollution.
Final conclusion
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QUESTIONS?
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THANK YOU