耦合液态乙烯冷能的液态空气储能系统热力学及经济性分析

Thermodynamic and economic analysis for a liquid air energy storage system coupling cold energy of liquefied ethylene

液态空气储能(LAES)技术因其高储能密度和与外部能源的灵活耦合特性,成为了一种重要的大规模储能技术。构建了一种回收液态乙烯再气化废冷、引入外部低温热源的LAES系统。从热力学和经济性两方面对压缩机等熵效率、膨胀机等熵效率以及热源温度等系统关键参数进行分析,结果表明:当乙烯流量为34 t/h,储能容量可达5 MW/40 (MW·h);在90%的压缩和膨胀等熵效率下,仅依赖25℃的环境热源加热空气,往返效率为77.45%;当热源温度提升至125℃时,系统的最优往返效率、净现值及动态回收期分别达到了106.99%、14 473万元和3.56年。该研究结果能为LAES系统与外部冷能的耦合研究提供参考。

Liquid air energy storage(LAES)technology stands out as a large-scale energy storage technology due to its superior energy storage density and adaptability to external energy sources.An LAES system that recovers waste cold of liquid ethylene and introduces an external low-temperature heat source is proposed.Moreover,thermodynamical and economic analysis on key parameters,including isentropic efficiency of the compressor and expander,and temperature of the heat source,are conducted.The results reveal that,when the ethylene flow rate is 34 t/h,the energy storage capacity can reach up to 5 MW/40(MW·h).At isentropic efficiency of the compressor and expander of 90%,the round-trip efficiency can achieve 77.45%by solely relying on an ambient heat source of 25℃ for air heating.When the heat source temperature is increased to 125℃,the system’s optimal round-trip efficiency,net present value,and dynamic payback period reaches 106.99%,144.73 million yuan,and 3.56 years,respectively.These findings provide reference for research on the coupling of LAES systems with external cold energy.