Systematic study of aqueous monoethanolamine (MEA)-based CO2 capture process: Techno-economic assessment of the MEA process and its improvements

The present study investigated the technical and economic performance of the monoethanolamine (MEA)-based post-combustion capture process and its improvements integrated with a 650-MW coal-fired power station. A rigorous, rate-based model developed in Aspen Plus® was employed to evaluate technical performance, while a comprehensive economic model was used to determine the required capital investment and evaluate economic performance. The techno-economic model was validated with published cost results. Our estimation of the capital investment for the baseline MEA capture plant was US$1357/kW, with a CO2 avoided cost of US$86.4/tonne. We then proposed process improvements such as parameter optimisation, lean/rich heat exchanger optimisation and flow sheet modifications to improve energy and cost performance. The combined process improvements reduced the capital investment by US$72/kW (a 5.3% saving) while cutting overall energy consumption by 24.5 MW/h (a 13.5% reduction). As a result, the CO2 avoided cost fell to $75.1/tonne CO2, a saving of US$11.3/tonne CO2 compared with the baseline. Lastly, we performed a sensitivity study and cost breakdown analysis to understand how the CO2 avoided cost would be apportioned to the economic and technical parameters. The results indicate the directions of technical development to further improve the economic viability of the CO2 capture process.