Energy-efficient process intensification for post-combustion CO2 capture: A modeling approach

High energy consumption remains a challenge for the amine-based post-combustion CO2 capture in thermal power plants. Process intensification is a feasible way to reduce heat requirement effectively in a CO2 capture process. In this work, we propose a hybrid post-combustion CO2 capture process configuration, aiming at lower energy consumption compared to conventional ones. The proposed process configuration features a pre-concentrating membrane, an intercooler, a rich solvent split configuration, and an air stripper. Typical aqueous monoethanolamine (MEA) with 30 wt% concentration is selected as absorbent. A rigorous rate-based method with corresponding thermal dynamic and chemistry models are employed to calculate the performances of the proposed CO2 capture process in Aspen Plus. Impacts of single process intensification configuration are analyzed separately to identify quantitative contribution of each of them to the overall performance improvement. Five different processes are presented and the reboiler duty can be reduced to a minimum in the last process due to the combination of the four configurations. Results show that a reboiler duty as low as 2.5 MJ/kg CO2 can be achieved by parametric optimization, which is 28% lower than that of conventional processes, leading to a reduction of 1.9% points in net power efficiency penalty.