Technical and economic assessment of iron and steelmaking decarbonization via power to gas and amine scrubbing

The iron and steel industry is one of the most energy-intensive industries, emitting 5% of the total anthropogenic carbon dioxide (CO₂). The control of CO₂ emissions has become increasingly stringent in the European Union (EU), resulting in EU allowance above 90 €/t_CO2. Carbon capture will be required to achieve CO₂ emissions control, and carbon utilization via power-to-gas could significantly increase interest in carbon capture in the iron and steel sector. This paper presents a new concept that combines amine scrubbing with power-to-gas to reduce emissions in blast furnace-basic oxygen furnace steelmaking plants. Synthetic natural gas (SNG) is produced using green hydrogen from water electrolysis and CO₂ from steelmaking. The synthetic natural gas is later used as a reducing agent in the blast furnace, constantly recycling carbon in a closed loop and avoiding geological storage. The oxygen by-produced via electrolysis eliminates the necessity of an air separation unit. By applying these innovations to steelmaking, a reduction in CO₂ emissions of 9.4% is obtained with an energy penalty of 16.2 MJ/kg_CO2, and economic costs of 52 €/t_HM or 283 €/t_CO2. A sensitivity analysis with respect to electricity and the CO₂ allowances prices is also performed.