Rongge Xiao, Yanwei Zhang, Xu Gao, Hongping Yu, Wangying Wei

Frontiers in Heat and Mass Transfer (FHMT) 15 - 22 (2020)

In order to improve DMR (double mixed refrigerant) liquefaction process and reduce operation cost of natural gas liquefaction plant, a four-stage DMR process optimization simulation calculation model was established through Aspen Hysys v8.4 and the purpose of the optimization model is achieved by using the segmented compression process in this paper. The minimum energy consumption and the highest exergy efficiency were used as the objective functions. By using the optimizer in HYSYS, the process parameters and ingredient proportion of the mixed refrigerant in the four-stage DMR process was optimized, and the best process parameters and ingredient proportion of the mixed refrigerant were obtained. According to process power consumption obtained by the optimization simulation, the ratio power consumption and exergy efficiency of the process were calculated. The liquefaction power consumption per unit quality of natural gas was 272.2kW/t and the liquefaction exergy efficiency was 46.85% in this paper. Comparing with the current DMR process power consumption in China, the energy consumption was significantly reduced.