Structural Arrangement of End Flash System for LNG Production

End flash system is important in LNG Chain as it increases LNG throughput by reducing the cooling load in Main Cryogenic Heat Exchanger (MCHE). One of the main problems encountered in industrial installations of end flash system is related in particular to the optimum use of the compression apparatus which represents a significant investment, both in terms of initial purchase and in terms of power consumption. The energy needed for the typical end flash system is approximately 995 kJ for the production of 1 kg of LNG. In this work, simulations on the structural arrangement of end flash system were conducted in the aim of reducing the specific power of production of LNG. The energy required to produce 1 kg of LNG and machinery power consumed by the end flash system are investigated. Two optimization cases, namely pure refrigerant cascade and mixed refrigerant cascade, have been studied and analyzed from technical and economical aspect. Results show that the base case needs 351 kJ to produce 1 kg of LNG while the mixed refrigerant cascade consumes only 273 kJ for the same purpose. Besides that, mixed refrigerant cascade gives higher LNG rundown at 542 t/h compared to the base case which gives only 540 t/h of LNG. In terms of economic analysis, the additional LNG rundown yields additional revenue of USD 13.6 million. The profitability analysis of installation of mixed refrigerant cascade over the base case shows positive feedback as ROI is 20.7% and IRR is 17.8% which is higher than the MARR. The study develops a new process which allows significant increase in LNG production with lower energy consumption as compared to the current end flash system.