Study on superheater wall temperature in a 1000 MW ultra-supercritical power plant under flexible load operations

To achieve the low-carbon transformation of the power system and the accommodation of new energy sources, coal-fired power plants are required to enhance the capacity for flexible peak regulation to maintain grid stability. Flexible peak regulation tends to cause over-temperature in superheaters of boiler, which in turn leads to tube bursting. In response to this problem, this paper analyzes the wall temperature variations of the superheater in a 1000 MW ultra-supercritical coal-fired unit during flexible load operation. It was found that the wall temperatures of the low-temperature superheater, platen superheater, and high-temperature superheater exhibited complex variations with significant temperature differences. In particular, the platen superheater showed more measuring points with maximum temperature difference under different electrical loads, reaching up to 165.1 °C, with minimum of the maximum temperature difference being 87.0 °C. The ceiling superheater, rear vertical shaft superheater, and horizontal flue bottom superheater experienced relatively uniform heating. Additionally, the study found that at a load of 643.9 MW, most of the superheaters experienced relatively uniform heating. These findings provide valuable references for operational control.