Integration of CASOH and DISPLACE technologies in a steel plant for the mitigation of CO2 emissions – A techno-economic analysis

Given the severe climate crisis and the urgent need to limit the adverse effects of global warming, drastic changes are required across various industries. Among them, the iron and steel sector is a major contributor to greenhouse gas emissions, accounting for approximately 7 % of global CO2 emissions. This study proposes the integration of innovative carbon capture technologies, such as DISPLACE and CASOH, into a conventional BF-BOF (Blast Furnace-Basic Oxygen Furnace) steelmaking process. A comprehensive techno-economic analysis was conducted, supported by simulations performed in Aspen Plus, to optimize the integration of these technologies. The study suggests a redesigned gas distribution system within the BF-BOF steel plant, incorporating oxy-fired units to facilitate post-combustion carbon capture and minimize the plant emissions. The analysis reveals that, employing CASOH for pre-combustion CO2 capture to decarbonize a mixture of BFG (Blast Furnace Gas) and BOFG (Basic Oxygen Furnace Gas), combined with DISPLACE for decarbonizing flue gases from hot stoves, sinter plant, and reheating ovens, 72 % reduction in CO2 emissions and a SPECCA around 0 GJ/tCO2 can be achieved. This is attainable within a renewable electricity scenario, at a cost of 138 € per ton of CO2 avoided. Lower CO2 avoidance values can also be achieved by treating less exhaust gases with reduction in both SPECCA and costs.