The Importance of Process Integration in the Iron and Steel industry

Size: px
Start display at page:

Download "The Importance of Process Integration in the Iron and Steel industry"


1 The Importance of Process Integration in the Iron and Steel industry Presentation by Lawrence Hooey Swerea MEFOS, Luleå, Sweden Nordic Recycling Day V, February 3 rd, 2010, Oulu University Content Swerea MEFOS PRISMA Process Integration Tools for modelling Modelling cases - how to reduce CO 2 -emissions in a steelplant - scrap charging to BOF - oxygen blast furnace - recycling of residual products Conclusions 1

2 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 2

3 PRISMA Centre for Process Integration in Steelmaking Nordic Recycling Day V, February 3 rd, 2010, Oulu University 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 3

4 The PRISMA research programme 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. 8 partners, 4 programme areas Process Integration TEMA AREA 1: Future Framtida production produktionssystem and process systems TEMA AREA 2: Optimal Optimum råmaterialdesign raw design TEMA AREA 3: Effektiva & uthålliga Sustainable energisystem energy strategies TEMA AREA 4: Residual Analys av restprodukter & products återvinningssystem and recycling systems Method development Method adaption 4

5 Process Integration Overall Steelworks site Global Integrated works Sinter plant Blast furnace Hot stoves Lime kiln Steel plant Ancillary- Onsite logistics & other Coke plant Rolling Heat and Power Plant Oxygen Plant Energy & material backpacks Raw materials Products Byproducts Pollutants Wastes Optimization Methodology 5

6 General Procedure Inputs ReMIND model System boundary Outputs Process 1 model 1. Define system boundary Process 2 model Process 3 model Sub-models in ReMind or discrete cases modelled in Excel 2. Develop/adapt sub-process models 3. Apply optimization routine: remind, Mixed Integer Linear Programming Layout of SSAB Luleå Works in Luleå Desulphurisation Svavelrening Ladle Skänkmetallurgi metallurgy Continuous Stränggjutningcasting Coke Koksverk oven Masugn Blast furnace Converter Konverter 6

7 plant Different ways to reduce CO 2 emission at SSAB Luleå Works 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 Potential reduction of CO 2-emissions, kg/t crude steel 7

8 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 CO 2 emission/ton steel Ask the shareholders: - increases profit 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! The Oxygen Blast Furnace Coke c.200 kg Ores Blast Furnace Top gas TG for firing the heater upper lower CO 2 Stripping Heater Recycle gas 70% CO CO 2 to CCS Export No export Gasgas For minimum coke rate Heater Off-gas Hot metal slag O 2 c. 230 Nm 3 Coal c. 170 kg 8

9 Example Process gas balance 700 MJ (cowpers) Coke Ovens Conventional Blast Furnace 240 MJ 2800 MJ 470 MJ CHP Plant Distance heat 1200 MJ Electricity 880 MJ 140 MJ 3510 MJ/thm BOF Impact of OBF on Process gas balance Conventional OBF installed Coke Ovens Coke Ovens Blast Furnace 240 MJ 2800 MJ 470 MJ CHP Plant 940 MJ 0 MJ 470 MJ OBF 3510 MJ/thm 1410 MJ/thm BOF Extra energy MJ/thm BOF What are electrical CO 2 emissions? Replacement energy for CHP? 9

10 CO 2 emission reduction example - OBF CO 2 emission reduction estimates - OBF % Direct Increased electrical consumption or decreased Decreased power heat production production include indirect credit for power Transport & Sequestration? credit for heat OBF without CCS OBF with CCS Common Nordic Solution - Background The annual production for the Nordic steelmaking sites are between kton Landfill volumes ~ kton/a per site Investment in alternative process is capital intense and requires larger treatment volumes 10

11 Centralised handling of residues 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 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 11

12 Thank you for your kind attention 12