Advanced Exergoeconomic Analysis of C3MR, MFC and DMR Refrigeration Cycles in an Integrated Cryogenic Process

Abstract

C3MR, MFC, and DMR processes in an integrated LNG-NGL-NRU structure are investigated using the conventional and advanced exergy and exergoeconomic analyses. The results of advanced exergy analysis reveal that in most of the equipment, the highest amount of irreversibility is occurred because of endogenous exergy destruction. In C3MR process, compressor C5 with 9730 kW; in MFC process, compressor C1 with 6342 kW; and in DMR process, compressor C3 with 10008 kW; have the most amount of avoidable endogenous exergy destruction in comparison with the other equipment. According to the advanced exergoeconomic analysis, the amount of endogenous part of exergy destruction cost and investment cost is higher than the exogenous part for most of the equipment, representing that interactions among the equipment is not considerable. Compressors have the highest amount of avoidable endogenous investment cost in all of the processes. Furthermore, in C3MR process, HX2 heat exchanger with 1121 $/h; in MFC process, compressor C1 with 450 $/h; and in DMR process, HX3 heat exchanger with 3955 $/h; have the most amount of avoidable endogenous exergy destruction cost. Based on total costs defined for the equipment, in C3MR process, HX2 heat exchanger with 1126 $/h should be modified. In MFC process, compressor C1 with 504.7 $/h should be considered. In DMR process, HX3 heat exchanger with 3963 $/h should be improved its performance. Finally, sensitivity analysis as well as validation have been conducted, and three different strategies are used to reduce the cost of avoidable exergy destruction of system equipment.