液化天然气冷能回收系统的设计与优化分析OA北大核心CSTPCD

The cold energy released during the liquefaction process of liquefied natural gas(LNG)is often underutilized.An LNG cold energy recovery system that combines refrigeration with power generation to effectively recover LNG cold energy was proposed.The system structure includes two-stage organic Rankine cycles(ORC),air conditioning(AC),and direct expansion cycle(DEC).Using HYSYS software,the system performance was simulated and analyzed.Genetic algorithm(GA)was employed to optimize the mixture ratio of the four-component working fluid(methane,ethane,propane and isobutane),evaporation pressure,condensation pressure,and primary expansion pressure in the system.Subsequently,an economic evaluation of the optimized scheme was conducted.The results show that the optimal mass fraction of the four-component working fluid for the front and rear stages of the ORC are 28.9%,57.3%,5.5%,8.3%and 0.4%,20.3%,56.4%,22.9%,respectively.In the optimized scheme,the net output power of the system can reach 218.28 kW,and the utilization rate of LNG cold energy,thermal efficiency and exergy efficiency are 54.69%,20.89%and 41.18%,respectively.The system exhibits good economic feasibility,with an economic and benefit of 160.30×104 CNY.The total investment cost of the equipment is 1215.91×104 CNY,and the levelized energy cost is 0.63 CNY/(kW·h),with an expected payback period of within 7.59 a.