The Importance of Process Integration in the Iron and ...
Transcript of The Importance of Process Integration in the Iron and ...
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Nordic Recycling Day V, February 3rd, 2010, Oulu University
The Importance of Process Integration
in the Iron and Steel industry
Presentation by Lawrence Hooey
Swerea MEFOS, Luleå, Sweden
Nordic Recycling Day V, February 3rd, 2010, Oulu University
Content
Swerea MEFOS
PRISMA
Process Integration
Tools for modelling
Modelling cases
- how to reduce CO2-emissions
in a steelplant
- scrap charging to BOF
- oxygen blast furnace
- recycling of residual products
Conclusions
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Swerea MEFOS
Metallurgical Research Institute
Performs joint research for Member Companies
Performs contract research for clients worldwide
Pilot plant facilities for iron & steel making
Hosting LKAB Experimental Blast Furnace
Pyro metallurgy
Heating and metalworking
LKAB’s Experimental BF
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Nordic Recycling Day V, February 3rd, 2010, Oulu University
PRISMA
Centre for Process Integration in Steelmaking
Institute Excellence Centres
” to bring together industry, institutes and universities in research of international standing in well defined, new areas to the benefit of the Swedish industry”
Joint activities at a research institute
Involvement of personnel from industry and university on a
significant scale
Much of the work done by senior researchers
Doctoral work is included to, among other things, create sustainable
relationships between research institutes, universities, and the industry
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Applies Process Integration in the ore processing, ironmaking and steelmaking processes,
Builds a solid foundation of techniques and tools, by the pursuit of implementing projects in collaboration with industrial partners,
Have a focus on effective use of resources with a system perspective, where resources can be energy, materials, environment, costs, etc.,
Based primarily on the established process knowledge and is a complement to the traditional process development.
The PRISMA research programme
8 partners, 4 programme areas
Method development
Method adaption
TEMA 1:
Framtida produktionssystem
TEMA 2:Optimal råmaterialdesign
TEMA 3: Effektiva & uthålliga energisystem
TEMA 4: Analys av restprodukter & återvinningssystem
AREA 1: Future
production and process systems
AREA 2:Optimum raw material design
AREA 3: Sustainable energy strategies
AREA 4: Residualproducts and recycling systems
Process Integration
Method development
Method adaption
TEMA 1:
Framtida produktionssystem
TEMA 2:Optimal råmaterialdesign
TEMA 3: Effektiva & uthålliga energisystem
TEMA 4: Analys av restprodukter & återvinningssystem
AREA 1: Future
production and process systems
AREA 2:Optimum raw material design
AREA 3: Sustainable energy strategies
AREA 4: Residualproducts and recycling systems
Process Integration
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Oxygen Plant
Heat and
Power Plant
Overall
Steelworks site
Sinter plant Lime kiln
Blast furnace
Hot stoves
Coke plant
Steel plant
Ancillary-
Onsite logistics
& other
Rolling
Integrated works
Energy &
material
“backpacks”
Global
Raw materials
Products
Byproducts
Pollutants
Wastes
Process Integration
Optimization Methodology
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System boundaryInputs Outputs
1. Define system boundary
Process 1 model
Process 2 model
Process 3 model…
Sub-models in ReMind or
discrete cases modelled in Excel
2. Develop/adapt sub-process models
ReMIND model
3. Apply optimization routine: reMIND, Mixed Integer Linear Programming
General Procedure
Layout of SSAB Luleå Works in Luleå
StränggjutningSkänkmetallurgiSvavelrening
Konverter
Koksverk
Masugn
Coke oven
Blast
furnace
Converter
Ladle
metallurgyDesulphurisation Continuous casting
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plant
Different ways to reduce CO2 emission
at SSAB Luleå Works
Potential reduction of CO2-emissions, kg/t crude steel
Process improvements
100% yield hot metal to crude steel
100% yield crude steel to slabs
Balanced liquid flow
Melting of scrap
Increased PCI rate
Reductant rate -20 kg/THM
Recycling +5 kg
Reduced flaring of BF-gas
More efficient heating of coke oven
Investments
Preheating hot stoves
Top pressure recovery
External cooperation
BF slag for cement production
Increased district heating
0 20 40 60 80 100 120 140 160
Utopisk hetvattenbalans
All slagg till slaggcement
Avgasturbin
Värmeväxlare cowpers
Undereldning
Minskad fackling
Recirkulering +5kg
Reduktionsmedel -20 kg/ton
Ökad kolinjektion
Skrotsmältning
Perfekt balans varma flödet
100% utbyte råstål till ämne
100% utbyte råjärn till råstål
Minskad emission vid hypotetiskt driftsfall, kg/ ton råstål
Processförändringar
Investeringar
Externt samarbete
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PI Example: Increase scrap in converter?
Ask the BF Manager:
- requires increase in HM Si & temp.
- increases BF coke rate & cost/thm
- reduces BF production
Ask the BOF Manager:
- increases productivity
- lowers raw material cost
Ask the environment manager:
- lowers CO2 emission/ton steel
Global implication with limited scrap supply:
The most sustainable solution, from an energy perspective, can be to use
the scrap in a converter at a steelplant with a lower efficiency blast
furnace!
Ask the shareholders:
- increases profit
Blast
Furnace
CO2
Stripping
Heater
CO2 to CCS
Recycle gas
70% CO
TG for firing
the heater
Top gas
Export Gas
Coke c.200 kgOres
O2 c. 230 Nm3
Coal c. 170 kgHot metal
slag
Heater
Off-gas
No export gas
For minimum coke rate
The Oxygen Blast Furnace
lower
upper
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CHP
Plant
240 MJ
2800 MJ
470 MJ
3510 MJ/thm
Conventional Blast Furnace
Coke Ovens
BOF
Example Process gas balance
700 MJ
(cowpers)
140 MJ
1200 MJ
880 MJ
Distance heat
Electricity
CHP
Plant240 MJ
2800 MJ
470 MJ
3510 MJ/thm
OBF
Coke Ovens
BOF
940 MJ
0 MJ
470 MJ
1410 MJ/thm
OBF installedConventional
Blast Furnace
Coke Ovens
BOF Extra energy 1000+ MJ/thm
What are electrical CO2 emissions?
Replacement energy for CHP?
Impact of OBF on Process gas balance
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CO2 emission reduction estimates - OBF
-10
10
30
50
70
90
Direct include
indirect
credit for
power
credit for
heat
%
OBF without CCS OBF with CCS
Increased electrical consumption
Decreased power production
or decreased
heat production
Transport
& Sequestration?
CO2 emission reduction example - OBF
Common Nordic Solution - Background
The annual production for the Nordic steelmaking
sites are between 600–2800 kton
Landfill volumes ~20-100 kton/a per site
Investment in alternative process is capital intense
and requires larger treatment volumes
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Idea
Invest in one installation for
treatment of all residues
Allows for an economy of scale
Logistics are suitable for the main
integrated works
Possible Technologies
RHF
Cupola Furnace
Detailed studies are underway
Centralised handling of residues
Conclusions
A process integration approach is important when evaluating
different ways of operating an integrated steel plant and for
evaluation of new technology
The result of an optimization can be quite different depending
on the selection of system boundary
E.g. The blast furnace compared to blast furnace + ancillary
operations + energy production in CHP plant
Communication of PI analyses to effectively convey the
results to all stakeholders must be further developed
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Thank you for your kind attention