Enhancing the ramp-up flexibility of the coal-fired power plant under deep peak shaving work conditions by adopting a sliding steam temperature Scheme

With the high penetration of renewable energy sources in China's power system, coal-fired power plants (CFPPs) fundamentally guarantee power supply and regulate power sources operating in load cycling and peak shaving. This paper established a dynamic model of the ultra-supercritical coal-fired power generation unit system to explore the potential of the ramp-up flexibility of CFPPs under deep peak shaving conditions. The load cycling rate is limited in low-load operation, and the fundamental reason lies in insufficient heat transfer capacity inside the boiler. Therefore, we propose a sliding temperature control strategy to improve the insufficient heat transfer capacity under low-load conditions and enhance the unit's flexibility from 30 % to 50 % Pe during the ramp-up process. The research results show that by adjusting the sliding temperature strategy, the boiler's operational stability and heat transfer performance are effectively improved, thereby enhancing the ability of CFPP to adjust the load rapidly. Step disturbances in feed water and coal feeding are carried out to test the performance of CFPP with four Schemes. With the sliding temperature Scheme, the necessary time to reach a new steady state is shortened by 15.33 %–21.22 %, and the maximum load cycling rate increased from 2.27 % to 3.37 % Pe min−1.