There is an increasing participation of thermal power units in peak shaving of power grid due to the national “double carbon” target and the strategic demand of energy transformation in China. The molten salt heat storage system can substantially improve the peak shaving capacity of thermal power system by absorbing or releasing heat efficiently from or into the thermal system. The key technologies of thermal power units coupled with molten salt heat storage system and the research progress of the heat storage system process flow design are combed in detail. Firstly

the formulas and physicochemical properties of commonly used molten salts are summarized. Great attention is paid to the characteristics and application prospects of the currently widely used binary and ternary nitric acid molten salts. Secondly

the critical equipment components including the thermal storage tank as well as heat exchangers used in the heat storage system are elaborated. The heat storage principle and characteristics of single-tank and double-tank molten salt heat storage methods are summarized

and the applicability of the former two methods to thermal power units' heat storage and peak shaving system is analyzed from the perspectives of system safety

cost

technology maturity and peak shaving response speed. Then

the current research status of molten salt heat exchanger is summarized

and the research achievements and shortcomings of molten salt-steamwater tube shell heat exchanger are emphatically analyzed from multiple perspectives. Moreover

the design schemes of molten salt heat storage system are sorted out emphatically for the process of heat storage system. The different design features of thermal storage systems are compared. Furthermore

some of the future work on the design of flexible-peak-shaving thermal storage system is also figured out. Finally

the design and practical application of molten salt heat storage system are prospected.