Performance analysis and comparison of cryogenic CO₂ capture system

Excessive energy requirement for the cryogenic condition is still the challenge for the current cryogenic CO2 capture system. In this work, the capture performance is investigated for the aim of energy savings on different cryogenic CO2 capture system, based on the combination of pressure recovery and cold energy utilization on the process residual gas. Based on this, two novel energy saving CO2 capture processes are proposed, which are defined as the post-expansion and the pre-cooled processes, respectively. The study presents a detailed comparison of the proposed process with conventional one regarding CO2 recovery and energy consumption. Also, the energy saving potential of two proposed processes is analyzed by varying the operating parameters, including process temperature, compression pressure, and inlet gas CO2 concentration. The simulation results show that the specific energy consumption can be decreased by 3.9% and 7.4% in the proposed post-expansion and pre-cooled process due to the effect of less cooling energy and compression work consumption, respectively.