Optimisation study of ironmaking using biomass

Abstract

The economic advantage of using biomass as partial substitute for fossil reductants in the blast furnace (BF) process was studied by simulation. A thermodynamic model of the BF was used in combination with simple models of the coke plant, sinter plant, hot stoves, basic oxygen furnace and power plant. Pretreatment of the biomass before its injection in the BF is considered in a pyrolysis unit where the carbon content and heating value are raised and the oxygen content is lowered, which is beneficial for the BF. The system was optimised with respect to the price of raw steel, considering costs of raw materials, energy and CO₂ emissions of the unit processes. The study demonstrates that biomass in partially pyrolysed form is a potential auxiliary reductant and that the optimal states of operation within certain regions depend strongly on the price structure of the raw materials and emissions.