超临界二氧化碳发电储能系统构型优化及性能分析

Configuration Optimization and Performance Analysis of Supercritical Carbon Dioxide Power Generation and Energy Storage Integrated System

为实现燃煤发电系统效率和灵活性协同提升,促进火电机组转型,提出采用超临界二氧化碳(S-CO_(2))工质、构建燃煤发电与热泵储电耦合的系统(“源储一体”系统)方案。基于热力学第一、二定律,建立集成系统的设计及变工况计算模型,进而对系统灵活性提升潜力和储—放热过程的能效进行分析。结果表明:在S-CO_(2)燃煤发电系统的基础上集成热泵储电技术,可将机组最小输出功率由30%额定负荷降低至0,极大提升了调峰深度和运行灵活性;当选择75%额定负荷为放热工况时,输出功率可增加额定负荷的23.59%,则集成系统的储—释热等效往返效率为78.64%。对储热参数进行敏感性分析,得到熔盐冷罐温度的最佳取值范围为405~420℃,常压水热罐温度的取值范围为70~75℃。

To synergistically enhance the efficiency and flexibility of coal-fired power system,and promote the transformation of thermal power units,a scheme of using supercritical carbon dioxide(S-CO_(2))working fluid to construct a coupling system of coal-fired power generation and pumped thermal electricity storage(“source-storage-integrated”system)is proposed.Based on the first and second laws of thermodynamics,the design and off-design calculation models of the integrated system are developed,and the potential of the flexibility improvement and the energy efficiency of the heat storage-release process are analyzed.The results show that by integrating pumped thermal electricity storage technology on the basis of S-CO_(2) coal-fired power system,the minimum output power of the unit can be reduced from the original 30%rated load to zero,which greatly improves the peak regulation depth and operation flexibility.When 75%rated load is selected as the heat release condition,the output power can be increased by 23.59%of the rated load.In addition,the equivalent round-trip efficiency of the heat storage-release process of the integrated system is 78.64%.The sensitivity analysis of heat storage parameters shows that the optimal value range for the molten salt cold tank temperature is 405~420℃,and the value range for the atmospheric pressure water hot tank temperature is 70~75℃.