Conceptual design, optimization and thermodynamic analysis of a CO2 capture process based on Rectisol

Abstract

Reducing CO2 emission is particularly important for environmental protection. Much absorbed CO2 in the conventional Rectisol process is discharged as tail gas due to the lacked attention to the by-product CO2. In this paper, a novel CO2 capture process, which is improved from the conventional Rectisol process, is proposed to reduce the emission of CO2. The revised CPA model shows a good performance and is used for the process simulation. Spin-up method is employed to optimize the CO2 capture process and uniform test method is used to further verify the optimization procedure. The results show that compared with the conventional Rectisol process, the system exergy consumption increases by 17.81%, but the exergy consumption per unit CO2 is 64.57% lower in the optimized CO2 capture process. The parameters in terms of the first-stage temperature Tfi, second-stage pressure Pse, and third-stage temperature Tth are analyzed, which show similar influence rules for the CO2 capture process. In addition, exergy distributions about the Rectisol process and the optimized CO2 capture process are investigated for the further thermodynamic analysis. This paper may guide for the improvement and optimization of more profound CO2 capture process.