Design and Economic Evaluation of the Increase to 95% CO2 Removal in Power Generation and Gas Discharge of a Steel Plant

Greenhouse gas emissions represent one of the most significant environmental challenges of the 21st century, with CO2 the major contributor, particularly in the steelmaking sector. To mitigate these emissions, carbon-capture, utilization, and storage technologies (CCUS) are considered the most mature technology, as they capture the CO2 from the blast furnace gas stream and utilize it in chemical production. Since monoethanolamine (MEA) remains the benchmark solvent used in post-combustion capture, this study focused on the process optimization and techno-economic evaluation of an MEA-based CO2 capture system to achieve 95% CO2 capture efficiency, which has still not been considered in detail in the literature. The optimization aims to achieve higher capture efficiency while minimizing the regeneration energy demand by investigating key parameters, including the absorber height, lean loading, regenerator height, regenerator pressure, and lean solvent inlet temperature. The results indicate that the absorber packed height and lean loading are the most influential parameters in increasing the capture efficiency from 90% to 95%, with optimal values of 20 m and 0.20 mol CO2/mol MEA, with an optimum value of 15 m for the regenerator height. Despite the capture target higher than 90%, the thermal energy requirement increased only marginally, from approximately 3.75 of the 90% CO2 removal system to 3.80 GJ/tCO2. A techno-economic assessment was then integrated to translate the process improvements into economic terms, considering the calculations of CAPEX and OPEX of the process, and a business plan was created to assess the effect and the application of the carbon tax on inflation.