The iron and steel (I&S) industry, an energy-intensive sector and one of the significant contributors to global CO2 emissions accounted for approximately 2.6 Gt of direct CO2 emissions in 2019. BFG has a higher ratio of CO and CO2 compared to other I&S off-gases (coke oven gas and basic oxygen furnace gas). On the other hand, BFG has lower LHV than the other two off-gases due to higher N2 and CO2 concentrations. Therefore, effective CO2 removal from BFG is more cost-effective than other off-gases due to the higher CO2 content in the BFG. Hence, BFG decarbonisation with novel cyclic technology, the Ca-Cu looping, is considered in this research and is integrated with a cryogenic CO2 separation unit. Aspen Plus® is utilised to develop the process modelling and performance evaluation. Techno-economic results revealed that an overall energy efficiency of 75.9% is achievable. The high cost of the plant (456.4 M€) is dictated by the high capital cost of the CASOH reactors (256.5 M€). Finally, considering 48.3 M€/y revenue from heat recovery and hydrogen-enriched syngas production, the total annualised cost of the plant is 118.1 M€ resulting in the cost of CO2 capture of 66.5 €/tCO2).

Authors: Navid Khallaghi, Shahan Ahmed, Maryam Malekshahian, Vincenzo Spallina