Exergy analysis of the biogas multistage compression process based on Aspen Plus simulation

Abstract

In this study, by taking the compression separation process of a biogas project as a research subject, a multistage compression process was simulated using Aspen Plus software. The exergy analysis of the biogas project under multistage compression and adiabatic or isothermal conditions was performed employing the thermodynamic principle. The results showed that the biogas exergy increased with pressure during the compression process and correspondently decreased in the interstage cooling process. Further, the compression series increased with the increase in efficiency, but the increase was gradual. The results of the example study of the four-stage compression process are as follows: the process exergy increased by ~83.07 kW, the process exergy efficiency was ~75.56%, and the recovery exergy potential was ~12.6 kW. In this study, the allocation of compression ratios and the selection of compression stages within the multistage compression process were analyzed by Aspen Plus was used to analyze., This analysis can ultimately help others design efficient multistage compression systems that reduce energy losses.