To enhance the peak shaving of coal-fired power plants and promote the large-scale consumption of renewable energy

this work proposes a coal-fired power plant coupled steam-flue gas stepwise heating molten salt thermal storage system

which extracts flue gas and main steam as heat sources to achieve deep peak shaving. In this study

an 1 100 MW power plant is taken as the research object. The simulation model is established by using EBSILON software

and the thermal load distribution from the heat source is carried out. The thermal storage properties

output power

coal consumption rate

denitration efficiency

and exergy efficiency of the coupling system with different thermal load distribution ratios are studied. The results show that the system can reduce the minimum electric load of the power plant from 40% to 21.24% of the rated load

with the highest equivalent round-trip efficiency of 69.71%. The minimum coal consumption rates in charging and discharging processes are 488.33 and 230.82 g/(kW⋅h)

respectively. Under a low load

the average temperature of denitration equipment inlet flue gas is increased by 41.5℃

and the denitration efficiency is increased by 10.88%. Under energy storage condition

the exergy efficiency of each system varies within 2%. Under energy release condition

the exergy efficiency of the boiler and the energy release system reaches up to 62.98% and 88.49%. In general

the proposed configuration has the advantages of strong peak shaving ability

high denitration efficiency and low exergy loss under low load

which provides a reference for the energy storage transformation of coal-fired power plants.