300 MW燃煤供热机组熔盐储热系统设计及经济性分析

Design and economic analysis of the molten salt heat storage system for a 300 MW coal-fired heating unit

火电机组深度调峰是保障电网稳定运行的重要措施。采用EBSILON软件建立国内某300 MW燃煤供热机组的热力学仿真模型,并通过对比仿真值与设计值验证了模型的准确性。为进一步提升机组负荷调节能力,选取并对比了抽主蒸汽及再热热段蒸汽加热熔盐的2种改造方案。以满足供热需求为基础,得到系统储/放热功率以及熔盐储热容量,并将熔盐储热系统耦合到原热力学模型中。通过模型计算得到了调峰时段的调峰深度以及非调峰时段的顶峰发电量,抽主蒸汽方案及抽再热蒸汽方案可分别提升34.26,19.30 MW的调峰深度以及14.77,12.33 MW的顶峰发电量。同时,对电力辅助服务市场及电力现货市场下系统的经济性进行分析。分析结果显示,在满足一定的调峰补贴或者峰谷电价差的情况下,改造项目资本金内部收益率能够达到10%。

Deep peak shaving for thermal power units is an important measure to ensure the stable operation of the power grid.A thermodynamic model of a 300 MW coal-fired heating unit in China is established by software EBSILON.The accuracy of the model is verified by comparing the simulation parameters with the design values.To further enhance the deep peak shaving capability of the unit,two molten salt heating schemes powered by extracted main steam and reheat steam are proposed.To meet heating demands,the molten salt heat storage system is coupled to the original thermodynamic model,considering the storaged/released heating power of the system and molten salt heat storage capacity.Based on the model,the peak shaving depth and the power generation during non-peak shaving period are obtained.The main steam extraction scheme and the reheat steam extraction scheme can increase the peak shaving depth by 34.26 MW and 19.30 MW,respectively,and raise the peak power generation by 14.77 MW and 12.33 MW.At the same time,the economic performance analyses of the system in the electricity auxiliary service market and the electricity spot market are carried out.The results show that under certain peak shaving subsidies or peak-valley electricity price differences,the capital internal return rate of the project can reach 10%.