储能的低温空气分离系统热力学与经济性分析

Research on Thermodynamic and Economic Performance of Air Separation Unit with Liquid Air Energy Storage

为探索低温空气分离系统(ASU)进行电力需求错峰运行的可行性,将传统空气分离技术与液态空气储能技术(LAES)结合,在谷电期先将富余空气压缩、液化、储存,在峰电期将液态空气作为精馏原料补充到精馏塔,以提高谷时压缩用电负荷、降低峰时压缩用电负荷。与传统空气分离系统相比,氧气产品的标准状态体积流量为10165m^(3)/h的低温空气分离储能系统(ASU-LAES)可将压缩能耗的20%由电网高峰时段转移到低谷时段,年度用电成本可减少1.3%~6.8%。ASU-LAES系统的制氧单位压缩能耗为0.349kW·h/m^(3),设备投资成本为4034.8万元,动态回收期为4.6~5.2a。ASU-LAES方案可缓解电网高峰负荷用电压力,充分利用峰谷分时电价政策优势,可创造良好的经济效益。

In this study,a combination of air separation unit and liquid air energy storage technology is employed to realize large-scale power demand management of a cryogenic air separation system.The surplus air is compressed,liquefied and stored during valley electricity periods,while the stored liquid air is directly recycled to the distillation column as raw material during peak electricity periods,thus increasing valley electricity consumption and decreasing peak electricity consumption.An air separation unit with liquid air energy storage(ASU-LAES)system producing oxygen with a standard state volume flow rate of 10165 m^(3)/h shifts the annual compression electricity consumption by 20%from peak periods to valley periods,resulting in a saving of 1.3%—6.8%per year on the electricity costs as compared to a conventional air separation system.The daily compression electricity consumption for oxygen production is 0.349 kW·h/m^(3).The equipment investment is RMB 4034.8×10^(4).The dynamic payback period is 4.6—5.2 a.The ASU-LAES system helps to reduce the peak power supply pressure of the power grid,takes advantage of the peak-valley electricity price policy,and brings economic benefits to the system.