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 highenergy 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.

Automated summary

In this study, a chemical absorption system using a 30% MEA solution was modeled and evaluated for CO2 capture in industrial clusters. The analysis showed that regulating the temperature of the stripper column was crucial in reducing energy consumption. A trade-off analysis revealed that the Levelized Cost of CO2 Capture was a more suitable metric for decision making. The study achieved potential cost reduction and thermodynamic improvement.