Comparison of different CO2 liquefaction processes and exergoeconomic evaluation of integrated CO2 liquefaction and absorption refrigeration system

Abstract

The liquefaction of captured CO2 from power plants is one of the means to prepare the CO2 stream for transportation to utilization or capture site. In this study, four CO2 liquefaction systems are compared in terms of their energy, exergy, and economic performance. It is concluded that the integrated absorption refrigeration system shows the best performance among all with a better exergy efficiency, and more than 20% lower capital, operational, and life cycle costs. To have a deeper insight into the performance of the integrated absorption refrigeration systems, an exergoeconomic analysis is implemented. The exergoeconomic factors related to the devices of this process show some considerable performance enhancement potentials, especially with the upgrade of heat exchangers. The share of both compression and refrigeration in liquefaction of the CO2 stream is investigated in energy analysis alongside with COP of each refrigeration system. The exergy destruction rates, exergy efficiency of equipment, and exergy efficiency of refrigeration systems are calculated in exergy analysis. In economic analysis, capital and operational costs, as well as the impact of different parameters on life cycle costs, are investigated. Finally, exergoeconomic analysis shows the cost flows in the integrated absorption refrigeration system, showing the share of different costs in the overall liquefaction process. The software packages used for this study are Aspen HYSYS V 11, Aspen Process Economic Analyzer, and Matlab.