A Study on the Potential of Carbon Dioxide Utilization Through its Co-Injection with Hydrogen into the Blast Furnace Tuyeres

The potential of CO2 utilization through its injection into blast furnace (BF) tuyeres is studied using the 1D steady-state zonal model. Scenarios with the injection of CO2, hydrogen, and their co-injection at various H2/CO2 mass ratios are analyzed. The impacts on factors affecting vertical temperature patterns and the position of the cohesive zone in the BF are identified. A life cycle assessment for several scenarios with various carbon emissions intensities of hydrogen production, carbon capture, and grid electricity generation is performed. Injection of CO2 without the addition of hydrogen increases the coke rate, reduces productivity, and increases direct CO2 emissions; however, thanks to producing top gas with higher calorific value, injection of CO2 may reduce the global warming potential (GWP) if the electric grid carbon intensity is above 654 kg-CO2 kWh-1, while carbon capture is powered by green electricity. Although the injection of hydrogen alone would result in a more substantial reduction of GWP from the baseline than the injection of H2/CO2 mix at any mass ratio, considering the identified impacts on heat exchange and the position of the cohesive zone in the BF, co-injection might be an enabling solution for the adoption of hydrogen injection. Hydrogen and carbon dioxide co-injection reduces coke rate, increases productivity, and reduces life cycle CO2 emissions of the blast furnace ironmaking. Injection of CO2 may reduce the global warming potential if the electric grid carbon intensity exceeds 654 kg-CO2 kWh-1, while carbon capture is powered by green electricity.image (c) 2023 WILEY-VCH GmbH