储能式低温空分系统热力学与经济性分析

Low−temperature air separation equipment is a high energy consumption link for large chemical systems. If it is combined with liquid air energy storage technology, it can effectively balance the load of the grid peak valley and significantly improve the economic benefits of the system. This paper introduces an air separation unit with energy storage and generation (ASU−ESG). It uses valley electricity to liquefy air and recovers liquid air for electricity generation and air distillation, thus reducing peak compression loads and improving load regulation ability. The results show that for an ASU−ESG system with an air processing capacity of 60000 m³∕h, the power consumption for oxygen production is 0.378 kW·h∕m³. The oxygen extraction rates for energy storage and energy release processes reach 89.46% and 93.71%, respectively. Compared with conventional ASU, the ASU−ESG improves compression load by 28% during off−peak electricity periods and reduces it by 20% during on−peak electricity periods, resulting in annual electricity cost savings of 5.72%—6.88%. The dynamic payback period for the ASU−ESG system is 3.3—4.3 a, and the net present value (NPV) reaches 19714.6×10⁴—28074.7×10⁴ CNY. The ASU−ESG system can balance the peak− valley fluctuation in power grids as well as obtain economic benefits in ASU operations.