A Cryogenic Power Cycle Based on Cold Energy of Liquefied Natural Gas and Solar Energy

摘要

Liquefied Natural Gas (LNG) at110K has plenty of physical cold exergy besides its high quality chemical energy. A combined cryogenic power cycle with natural gas directly expanding and a second refrigerant cycle for recovering LNG cold energy has been established by using a low grade-heat source, such as solar energy. Some correlative parameters, which affect the efficiency of the cycle, have been investigated. The results indicate that the temperature of the solar heating water and the inlet pressure of the turbine in natural gas directly expanding cycle are the key factors, which affect the cryogenic power cycle. The thermal and exergy efficiencies will improve with an increasing of the temperature of the solar heating water and the inlet pressure of turbine. The thermal efficiency and exergy efficiency of the power cycle will be above 30% and 40% respectively, after the key parameters are optimized. The cryogenics power cycle for recovering cold energy of LNG based on solar energy not only reasonably utilizes the solar energy but also efficiently recovers and applies the energy consumed during the liquefaction process.