Proposal of high-efficient recovery schemes of liquefied natural gas cryogenic energy

LNG is a kind of high-quality and cryogenic clean fuel. Due to its characteristic at tow temperatures, plenty of cryogenic energy can be utilized during the LNG gasification process. The cold energy recovery and utilization might be performed in two ways.. i.e. cold exergy utilization and cooling capacity recovery. A simple thermal engine with Stirling cycle between atmosphere and LNG is proposed as an efficient example of cold exergy utilization in this literature. Moreover a novel air separation system using LNG as cold sink is put forward to recover the LNG cryogenic capacity. The thermal performances of the both novel systems are analyzed and calculated respectively. According to the analysis and calculation, the exergy efficiency of the Stirling engine system is higher than that of the combined cycle used in power plants. The air separation system with LNG as cooling source can save a considerable amount of power energy. The power consumption of per-kilogram liquid product may decrease by 54%.