Study On Integrated Power/Refrigeration System And Low CO₂ Emission Power System With LNG Cryogenic Energy Utilization

As one of the most important subjects of thermodynamics,the research and development of high-efficient and environmental friendly thermodanymic cycles is regarded as the basis and source of sustainable development.Supported by the NSFC (No.50576096)and International Collaboration Project,CAS-IET(No.4501149361), this research is to study the basic coupling modes and to reveal the system integration principle of the Integrated Power/Refrigeration System(IPRS);to propose and investigate a novel IPRS;to propose and investigate a novel low CO₂ emission power cycle with the LNG cryogenic energy utilization.The main contents are as follows:The first is to find out the most energy-consuming unit and the key to improve cycle performance of the IPRS by performing energy and exergy balance analysis to the two most basic coupling modes:the series connected and paralled connected.As a result,the integration principle of the IPRS is revealed and concluded.The second is to proposed and investigate a novel IPRS with adjustable ammonia concentration based on the integration principle,which distinguishes itself by adjusting the ammonia concentration of working fluid in the key process through an splitting-absorption unit.The novel IPRS can achieve an exergy efficiency of 57.6% with turbine inlet temperature of 450℃,and consume 18.2%and 2.4%less energy than the separate generation system and cogeneration system with the same outputs.It is proved that using the novel IPRS as the bottom cycle is helpful to improve the thermal performance of combined cycle.A research on reclaiming the mid-level pressure and heat energy is carded out to the novel IPRS,several novel approaches are proposed and proved to be useful for the recovery of cycle internal energy and reduction of ammonia/water turbine backpressure.The third is to propose and investigate a novel high efficient power system with LNG cryogenic energy utilization and low CO₂ emission,the integration of the LNG evaporization unit and the power cycle condensation process realizes the CO₂ separation with zero power consumption and the near zero CO₂ emission.An optimal cycle mode is decided by the thermal and economic comparison with the other different ones.The thermodynamic and economic analysis shows that the optimal cycle with turbine inlet temperature of 900℃can achieve a thermal efficiency of 59%,CO₂ recovery rate of 99%and specific cost of 1,075＄/kW.