Feasibility analysis of peak shaving for coal-fired units based on molten salt heat storage
With the continuous increase of installed capacity of new energy generation in power grid,thermal power units have to undertake more peak shaving.However,the flexibility and peak shaving capacity of current thermal power units are generally insufficient.A subcritical 300 MW coal-fired unit is retrofitted for molten salt energy storage.Six heat storage strategies and two heat release strategies are proposed and investigated.The influence of heat storage and release process on the peak shaving capacity and thermal performance of the unit under three working conditions is analyzed,the technical and economic analysis is performed in terms of the net present value.The results show the feasibility of extracting reheated steam for heat storage is higher,with a peak shaving depth of 58.9％.However,the coal consumption would increase at the same time.During the releasing heat stage,the maximum increment of power generation up to 11.3％of the rated power generation is achieved by heating the water supply to generate steam,while the higher temperature of the molten salt is required.Using high-temperature molten salt instead of low-pressure heater to preheat water supply is proved to have more advantages,while the power generation increment is relatively small.During the whole process of heat storage and release,the maximum circulating electricity efficiency can reach 0.987.The economic analysis of heat storage transformation is conducted.The dynamic investment payback period is 11.65 years,and the net present value is 49.118 million yuan.Therefore,the renovation scheme is feasible.
molten salt heat storagepeak shaving capabilitythermal performancenet present value
国家科技期刊平台
NSTL
万方数据
维普
