Energy, Exergy, and Exergoeconomic (3E) Analysis of Gas Liquefaction and Gas Associated Liquids Recovery Co-Process Based on the Mixed Fluid Cascade Refrigeration Systems

In this study, energy, exergy, and exergoeconomic analysis is performed on the recent trend of joint production of liquefied natural gas and natural gas liquids based on mixed fluid cascade most important of refrigeration systems. The proposed process is first simulated and exergticly analyzed, and finally, an economic model is used to analyze the exergoeconomic performance. The results include the cost of exergy destruction, exergoeconomic factors, and exergy efficiency. The exergy analysis results show that the proposed process’s exergy efficiency is about 53.84%, and the destruction rate is 42618 kW with LNG and NGL production rates of 69.00 kg/s and 27.42 kg/s, respectively. Also, results show that the maximum exergoeconomic factor, 69.53%, is related to the second compressor in the liquefaction cycle. The lowest exergoeconomic factor, which is 0.67%, is related to the fourth heat exchanger in the liquefaction cycle. In this process, the distillation tower has the highest relative cost variation (100.81), and the first air cooler in the liquefaction cycle has the smallest relative cost difference (1.08). One of the most costly economic factors is the cost of exergy destruction rates. The second heat exchanger has the exergy destruction cost (768.93 $/GJ), and the first air cooler in the liquefaction cycle has the lowest exergy destruction cost (19.38 $/GJ).