Exergy and economic analysis of the trade-off for design of post-combustion CO2 capture plant by chemical absorption with MEA

CO2 abatement strategies are crucial in any industrial cluster. In post-combustion capture solutions, the high-energy consumption and the cost associated with the operation are the main drawbacks. In this work, a chemical absorption system using a 30% MEA solution was modeled to process 3,240 t/h of flue gases with 12% CO2 content, and evaluated for design insights and their potential cost reduction and fewer energy losses, thus providing a screening tool for design and scale-up. Thermodynamic analysis showed that regulating the inlet temperature of the stripper column was pivotal in decreasing exergy destruction and heat consumption. A trade-off analysis allowed tracing their influence on system metrics, with absorber parameters being critical. Nevertheless, minimizing the Levelized Cost of CO2 Capture proved to be a more suitable metric for decision-making compared to either heat consumption or exergy efficiency. Solutions were ranked based on TOPSIS tool, which confirmed the most relevant design parameters. The potential operational expense savings (20 USD/t CO2), and thermodynamic improvement (52%), were achieved. Although capture cost values are within the expected industrial range for mature capture technologies (70 USD/t CO2), these are still far away from current taxes and levers for curbing emissions.