Using cryogenic exergy of liquefied natural gas for electricity production with the Stirling cycle

Cryogenic generation is one of the most important ways to utilize cold energy during LNG (liquefied natural gas) regasification. This paper fundamentally investigates LNG cryogenic generation with the Stirling cycle method based on previous studies. A basic process of LNG cryogenic generation with the Stirling cycle was presented initially with seawater and LNG as heat source and heat sink. And its thermodynamic analysis was performed to verify the theoretical feasibility of the Stirling cycle method. The generating capacity, the exergy efficiency and the cold energy utilization efficiency of the basic process were also calculated. Subsequently, the influences of evaporation pressure on net work, equipment performance and comprehensive efficiency of cold energy utilization were discussed and the effect of LNG mass flow as well as the ambient temperature was also studied. Finally an improved process of LNG cryogenic generation with Stirling cycle method combined with an air liquefaction process is proposed as feasibility in improvements of the basic process. •We propose a basic process of LNG cryogenic generation with the Stirling cycle.•Seawater and LNG were applied as heat source and heat sink of the basic process.•The max generating capacity of the basic process is 51 kWh/tLNG.•The max cold energy utilization efficiency of the basic process is 0.56.•We also discussed some feasibilities of optimization of the basic cycle.