EVALUATION OF THE POSSIBILITY TO UTILIZE BIOMASS IN FINNISH BLAST FURNACE IRONMAKING

Transcription

1 EVALUATION OF THE POSSIBILITY TO UTILIZE BIOMASS IN FINNISH BLAST FURNACE IRONMAKING Scanmet IV 4th International Conference on Process Development in Iron and Steelmaking, June 2012, Luleå, Sweden H. Suopajärvi & T. Fabritius

2 Topics discussed Introduction Methodology Layered sustainability assessment Integrated steelwork modeling resources Results Plant site assessment Availability of biomass Sustainable utilization of biomass Discussion and conclusions

3 Introduction European steel industry and CO 2 Policies to decrease emissions get stricter CO 2 allowance prices? Several new iron and steelmaking technologies are examined ULCOS is the leading party in Europe to develop more environmentally sound technologies Top-gas recycling BF, Hisarna, Ulcored, Ulcowin in blast furnace Used at least in Brazil Ongoing projects in several locations Bioreducer project in Finland (University of Oulu) Availability of domestic biomass Possibilities in Finnish blast furnace ironmaking

4 Sustainability Layered sustainability assessment Evaluation of new solutions need larger system view Compare e.g. TGR-BF and energy deficit in power production LCA is good tool, but not sufficient Layered sustainability assessment Important factors are examined separately in defined system boundaries Tools and metrics can be defined casespecifically use in Finnish BF ironmaking: Process behavior Fossil fuel replacement Plant site system Energy flows Surrounding society Availability assessment Plant site Process Surrounding society - Time

5 Integrated steelworks model - Simple mass and energy balance model was constructed for steelworks Changes in energy flows was the main interest

6 Unit process models Modeling and simulation done with Factory Simulation tool Blast furnace Chemical and thermal reserve zone between upper and lower active zones Calculates e.g. the needed coke and blast amount, slag amount and the composition of top-gas Charcoal plant Wood moisture 30 % (air dried) Drying: 3 MJ/kg H 2 O Pyrolysis: 2 MJ/kg dry biomass and moisture vaporization Energy from pyrolysis by-product burning

7 resources Several alternative feedstocks would be available for reducing agent production Wood Timber, pulp wood, logging residues, saw mill by-products (bark, chips, saw dust), demolition wood Agricultural residues (Plastic) (Peat) The wood-based raw material is basically the only potential source if large amounts are to be used Forest chips from tree tops, branches, stumps and small-diameter wood are considered because they are have the lowest price The industrial wood cuttings influence the amount of available forest chips

8 resources Forecast into 2020 because the use of forest chips is higher at that time The availability of forest residues in 2020 is based on the forecast of commercial cuttings of 67.9 Mm 3 Coefficients used are from the literature and used widely in assessing the energy wood potential The calculated potential is techno-ecological Ecological constraints and willingness to offer residues for sale are considered The demand side of the forest chips is based on the projected use in energy production in 2020 Pine Spruce Birch North South North South North South Logging residues Removal only from final fellings 70% 70% 70% 70% 70% 70% Yield per m 3 of stem wood 28% 21% 68% 44% 36% 21% Ecological constraint Between 57-89% depending on the forest center Recovery rate 70% 70% 70% 70% 70% 70% Willingness to offer logging residues to market 90% 90% 90% 90% 90% 90% Stumps Removal only from final fellings 70% 70% 70% 70% 70% 70% Yield per m 3 of stem wood 40 % 31% 32% 28% 35% 31% Ecological constraint Between 82-88% depending on the forest center Recovery rate 85% 85% 90% 90% 90% 90% Willingness to offer logging residues to market 70% 70% 70% 70% 70% 70%

9 Plant site assessment Three different charcoal injection scenarios Oil and charcoal co-injection 90, 75/15, 50/70 kg/thm Pure charcoal injection 150 kg/thm Stable BF operation can be maintained by adjusting oxygen enrichment and flux ratio Major changes in gas flows Coke oven gas distributed to hot rolling and slab furnace (need for high calorific valued fuel) Pyrolysis by-product utilization in power plant could provide large share of needed electricity in high charcoal use scenarios Up to 2.95 GJ/tHM additional energy from pyrolysis gas Coke production could be decreased significantly A C BFG 2.51 GJ COG 0.11 GJ Coal 493 kg BFG 158 Nm 3 COG 58 Nm 3 Air 972 Nm 3 O 2 58 Nm 3 BFG 617 Nm 3 Coal 460 kg CO kg CO kg BFG 207 Nm 3 COG 43 Nm 3 Air 943 Nm 3 O 2 57 Nm 3 BFG 616 Nm 3 CO 2 85 kg 333 kg PUG 0.89 GJ CO HS CO HS PP COG 222 Nm 3 CO kg CO kg Coke kg Blast 1030 Nm 3 COG 207 Nm 3 CO kg PU Oil 90 kg Coke kg Blast 1000 Nm 3 PUG 2.26 GJ Electricity 204 kwh Pellet 1307 kg Briquette 100 kg CaCO 3 52 kg BF BFG 2.14 GJ COG 0.11 GJ PUG 1.38 GJ BF BFG 1531 Nm 3 HM 1000 kg Slag 186 kg PP CO kg Electricity 282 kwh Pellet 1307 kg Briquette 100 kg CaCO 3 49 kg BFG 1493 Nm 3 HM 1000 kg Slag 181 kg Oil 50 kg Charcoal 70 kg B Coal 494 kg CO kg BFG 161 Nm 3 COG 58 Nm 3 Air 982 Nm 3 O Nm 3 D BFG 635 Nm kg PUG 0.19 GJ Coal 419 kg CO kg CO kg BFG 237 Nm 3 COG 31 Nm 3 Air 906 Nm 3 O 2 57 Nm 3 BFG 611 Nm 3 CO kg 714 kg PUG 1.90 GJ CO HS COG 223 Nm 3 CO kg PU CO HS Coke kg Blast 1035 Nm 3 PUG 0.49 GJ BFG 2.39 GJ COG 0.11 GJ PUG 0.30 GJ Oil 75 kg Charcoal 15 kg COG 189 Nm 3 CO kg PU Coke 326 kg Blast 963 Nm 3 PUG 4.85 GJ Charcoal 150 kg BF PP BFG 1.84 GJ COG 0 GJ PUG 2.95 GJ Pellet 1307 kg Briquette 100 kg CaCO 3 52 kg BFG 1532 Nm 3 HM 1000 kg Slag 186 kg BF PP CO kg Electricity 217 kwh Pellet 1307 kg Briquette 100 kg CaCO 3 46 kg BFG 1447 Nm 3 HM 1000 kg Slag 175 kg CO kg Electricity 373 kwh

10 Plant site assessment Calculation of the CO 2 emissions for the whole system indicate significant decrease in fossil CO 2 emissions, up to 26.1 % (from 1780 to 1315) Total CO 2 emissions increase from 1780 to 2215 kg/fu, but biomass-based emissions are considered neutral Widening the system even more, additional decrease in fossil CO 2 emissions could be achieved Considering the CO 2 emissions of electricity production LCA could be suitable tool for assessing wider effects

11 Availability of biomass in Finland The use of forest chips in heat and power plants was 6.2 Mm 3 in Techno-ecological potential in 2020 is 23.3 Mm 3 The projected potential to use forest chips in heat and power plants in 2020 is around 14.7 Mm 3 It seems that there is 8.6 Mm 3 forest chips potential But: Three biodiesel production facilities are under consideration in Finland with 2 Mm 3 forest chip need each Raw material is located in remote locations with long transportation distances

12 Availability of biomass in Finland a) b) c) d) Use 2010 (1000 m 3 ) Techno-ecological potential 2020 (1000 m 3 ) Technical potential in energy production 2020 (1000 m 3 ) Techno-ecological potential minus use in energy production 2020 (1000 m 3 ) (-999)-(-500) (-499)

13 Yearly biomass need Mt Sustainable utilization of biomass Depending on the fossil fuel replacement ratio, the amount of needed wood can be very high In the maximum scenario examined here (150 kg/thm), the need of wood could reach 6.1 TWh (~3 Mm 3 ) 2.6 Mt hot metal production assumed In nation wide evaluation, there would be raw material available Economic sustainability from the viewpoint of steel producer is missing today The future development of fossil reductant prices and EU policies may change the status quo Efficient utilization of pyrolysis byproducts have huge impact on the economics % yield 30% yield 35% yield Injected amount of charcoal kg/t HM

14 Sustainable utilization of biomass a) Centralized production collection collection Supporting processes Air Separation Plant Power Plant Iron and steelmaking Coke Plant transportation densification transportation transportation drying Pyrolysis/ Gasification Chemicals Reducing agent Heat BOF Crude steel b) Decentralized production collection Heat and Power Applications Chemicals Supporting processes Power Plant Iron and steelmaking Coke Plant transportation Pyrolysis Reducing agent transportation Reducing agent preparation Reducing agent BOF Crude steel Bio-based reductant production could be centralized or decentralized Integration with energy, chemical and even forest industry could be possible Other conversion technologies and biomass-based products could also be applicable to blast furnace injection Fast pyrolysis bio-oil Gasification synthesis gas Gasification and methanation bio-sng

15 Discussion and conclusions The analysis showed that there is potential to use domestic biomass in Finnish ironmaking Fossil CO 2 emission decrease could be significant Technological constraints in injection concerning Finnish BF:s is major factor Based on liquid oil injection Economic sustainability i.e. cost of biomass-based reducing agents is to be covered in future studies The effect of EU policies will have great effect in the future Process integration with other industries (industrial symbiosis) could provide more economically feasible solutions Other thermochemical conversion processes and products should be evaluated

16 Thank you!