Energy and advanced exergy analysis of an existing hydrocarbon recovery process

Highlights: • Advanced exergoeconomic analysis is performed for propane refrigerant system. • Avoidable/unavoidable & endogenous/exogenous irreversibilities were calculated. • Advanced exergetic analysis identifies the potentials for improving the system. - Abstract: An advanced exergy analysis of the Ethane recovery plant in the South Pars gas field is presented. An industrial refrigeration cycle with propane refrigerant is investigated by the exergy analysis method. The equations of exergy destruction and exergetic efficiency for the main cycle units such as evaporators, condensers, compressors, and expansion valves are developed. Exergetic efficiency of the refrigeration cycle is determined to be 33.9% indicating a high potential for improvements. The simulation results reveal that the exergy loss and exergetic efficiencies of the air cooler and expansion sections respectively are the lowest among the compartments of the cycle. The coefficient of performance (COP) is obtained as 2.05. Four parts of irreversibility (avoidable/unavoidable) and (endogenous/exogenous) are calculated for the units with highest inefficiencies. The advanced exergy analysis reveals that the exergy destruction has two major contributors: (1) 59.61% of the exergy is lost in the unavoidable form in all units and (2) compressors contribute to 25.47% of the exergy destruction. So there is a high potential for improvement for these units, since 63.38% of this portion is avoidable.