660 MW 超超临界燃煤发电机组湿态运行动态响应特性分析

The main technical challenges for ultra-supercritical coal-fired power plants in low-load flexible operation are the long state conversion time between dry and wet state, and the unclear safety boundary for wet state operation. In this paper, a dynamic model of the wide-load operation of a ultra-supercritical coal-fired power generation unit and a water wall temperature analysis model were established. The dynamic response characteristics and the water wall temperature distribution after the boundary conditions change during wet state operation were discussed. The results show that when the water wall recirculation water flow increases by 20%, the economizer inlet water temperature will increase by 9.7^◦C, the under-enthalpy of the work medium entering the water wall will decrease, and the maximum wall temperature of the water wall will increase by 16.9^◦C. When the boiler fuel supply rate increases by 5.0%, the separator outlet temperature will increase by 4.2^◦C, the unit output power will increase by 4.1 MW, and the quality of the steam/water will increase. Under the limitation of wall overtemperature, the orderly utilization of heat storage in the recirculation system is conducive to achieving smooth, flexible, and safe state conversion during low-load operation.