Swerea Nefos AB (Luleå, Sweden)

L. Sundqvist Őkvist, Prof., Senior Researcher, Process Metallurgy Dept., e-mail: lena.sundqvist@swerea.se
J. Orre, Mag. Sci.
M. Brämming, Dr., Process Integration Development
M. Lundgren, Dr., Process Metallurgy Dept.

SSAB Europe (Luleå, Sweden)
P. Lagerwall, Mag. Sci., Ironmaking Dept.

SSAB Special Steels (Oxelösund, Sweden)
B. Sundelin, Mag. Sci., Strategic Production Development

HBI charging has also the potential to significantly reduce the CO₂ emission at the BF but for using high amounts as e. g. 50% the production rate should preferably be increased. Lowed added amounts like 20% of HBI or some other scrap product can be used for lowering of CO₂ emission and especially if a slight increase of the production rate is desired. The combined cases with lower amount added in terms of biomass products for injection together with top charging of charcoal as well as HBI addition was shown to give effects up to around 20–30%. This could be an advantage from BF operation point of view as the overall process is likely less influenced by such modifi cation. Top gas recycling has been proven in experiments to give the savings that have been estimated in the modeled cases. As the top gas will be used for BF operation others as e. g. oil, NG, COG, biogas or biomass have to be used in heating furnaces, for district heating and power plants. Moreover, it will need installation of CO₂ capture plant and enlargement of oxygen production capacity. By limiting the hot gas temperature to 850 ºC and using metallic heat exchangers the hot stoves are available for periods with conventional BF operation.

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