Pilot test and process modification of CO2 chemical absorption for top gas recycling-oxygen blast furnace

The steel industry contributes approximately 7–9 % of global anthropogenic CO 2 emissions. Chemical absorption is a promising strategy for reducing steel industry carbon emissions. MAA, a novel amine blend primarily composed of methyldiethanolamine (MDEA) and 2-(Piperazin-1-yl) ethanamine (AEP), exhibits potential but lacks industrial-scale validation. Focusing on the blast furnace (BF)-basic oxygen furnace steelmaking process, this study conducted pilot tests with MAA and 30 wt% MEA for BF gas (20 vol% CO 2 ) and top gas recycling-oxygen blast furnace (TGR-OBF) gas (35 vol% CO 2 ) and studied process modifications. The results showed that after 200 h of stable operation, MAA achieved optimal CO 2 capture from BF gas at a liquid-to-gas ratio of 8 L/Nm 3 , with a regeneration energy of 2.47 GJ/t CO 2 , compared to 3.78 GJ/t CO 2 for 30 wt% MEA. MAA achieved a regeneration energy of 1.81 GJ/t CO 2 for TGR-OBF gas, 26.72 % lower than that for BF gas. Absorber intercooling reduced regeneration energy by 8.86 %. Among the process modifications, directing 10 % of the rich solution to a flash evaporator for semi-lean solution recycling back to the middle of the absorber, with the remaining 90 % undergoing thermal regeneration in the stripper, demonstrated the lowest regeneration energy for TGR-OBF. This modification reduced MAA regeneration energy by 5.52 %. Additionally, two-stage water scrubbing effectively controlled amine emissions from the 10 Nm 3 /h pilot plant, reducing MAA emissions to 17.83 mg/Nm 3 after the second stage. MAA exhibited excellent adaptability to BF and TGR-OBF gases, achieving 90 % CO 2 removal efficiency with a minimum regeneration energy of 1.71 GJ/t CO 2 . The findings highlight the potential for the large-scale application of MAA in the steel industry to significantly reduce CO 2 emissions.