A comparison of carbon capture and biomass utilisation for decarbonising oxygen blast furnace ironmaking

The Iron and Steel industry stands as a significant industrial source of CO2 emissions, contributing 7% to the global CO2 emissions. Therefore, innovative methods for CO2 removal must be developed in the current path to heavy-industry decarbonization. This work presents and compares two low-carbon brownfield concepts, integrated in an existing steelmaking plant, which incorporates power-to-gas technology, top gas recycling and oxygen blast furnace. The first concept captures carbon via calcium looping and uses it as the source for the methanation plant to produce synthetic natural gas, which is injected in the blast furnace as reducing agent. The second concept is based on charcoal and syngas production through biomass pyrolysis. The former is pulverized and injected into the blast furnace, replacing part of the fossil coke used in the reference steelmaking plant. The latter is used as carbon source in the methanation stage, avoiding the carbon capture stage. Promising results are obtained for the concept which uses biomass as carbon source in the process, achieving a CO2 abatement cost of 64.5 €/tCO2. It is estimated that this cost could be reduced to 55.4 €/tCO2 by scale economy. Despite current economic challenges, the potential mid-term profitability, driven by the ongoing deployment of renewable energy, identifies the utilization of biomass as a solution for environmentally conscious steelmaking.