Abstract: This paper presented a simulation of liquefied natural gas process of the mixed refrigerant cycle using Aspen Plus software，and calculated the exergy losses of each unit. The results showed that the exergy loss of compression process was 63.8% of all energy loss，heat transfer process accounted for 19% of the energy loss，but was the key point to reduce the exergy loss in the entire process. On the basis of the process simulation，the pressure and temperature of high-pressure refrigerant，low-pressure refrigerant，and the molar content of methane and n-pentane in the mixed refrigerants were selected as the variables in the detailed analysis of the impacts on the exergy losses. Suggestions were proposed to reduce the system effective loss. The analysis results showed that improving the high-pressure refrigerant pressure，low-pressure refrigerant pressure and temperature，and the molar content of the n-pentane in the mixed refrigerants could help reduce the exergy loss of the entire process. Reducing the high-pressure refrigerant temperature and the molar content of the methane in the mixed refrigerant process had similar effects.

Key words: liquefied natural gas (LNG), Aspen Plus, energy analysis, exergy loss

摘要： 采用Aspen Plus化工模拟软件对混合制冷剂液化天然气过程进行全流程的模拟计算，并对各个单元设备进行有效能分析。结果表明：压缩机的有效能损失占整个流程有效能损失的63.8%，换热过程占19%，是流程中的节能重点。在流程模拟的基础上，以高压制冷剂的压力和温度、低压制冷剂的压力和温度及混合制冷剂中甲烷与正戊烷的摩尔含量为可变因素，分析了这些因素对各设备有效能损失的影响，找出相应的影响规律，并提出了相应的降低体系有效能损失的措施与建议，对整个工艺过程的节能降耗具有一定的指导作用。结果表明：提高高压制冷剂的压力、低压制冷剂的压力与温度和混合制冷剂中正戊烷的含量，以及降低高压制冷剂的温度与混合制冷剂中甲烷含量的含量，有助于降低整个流程的有效能损失。

关键词: 天然气液化, Aspen Plus, 能量分析, 有效能损失