Research and application of new feedwater heating technology based on deep peak shaving of thermal power units

The biggest problem faced by the flexibility transformation of coal-fired power plants is the wide load denitrification of the boiler. As a wide load denitrification technology, raising the temperature of the feedwater can improve the inlet flue gas temperature of the boiler SCR during low load operation of the unit, ensuring the safe operation of the denitrification catalyst. This article takes Inner Mongolia Jingneng Shengle Thermal Power Co., Ltd. (hereinafter referred to as “Shengle Thermal Power”) 350MW Supercritical Unit 2 Flexibility Transformation Project as the research object, and conducts a pure condensing condition test of the unit. The minimum DC load of the boiler is 35% BMCR, corresponding to a power generation output of 40% THA of the unit. Firstly, the goal of 30% THA boiler non conversion flexibility transformation was established, and a new electric thermal collaborative feedwater heating technology was proposed by integrating the current mainstream flexibility transformation technology route. This technology can effectively improve the safety of boiler low load denitrification system operation, facilitate low load stable combustion of the unit, and move the supercritical boiler conversion point forward to below 30% BMCR. The performance test after the transformation showed that under pure condensing conditions, the minimum electrical load of the boiler non rotating unit decreased to 24.8% THA and maintained safe and stable operation for 6 hours. During this period, the average flue gas temperature at the inlet of the denitration SCR was not less than 295 °C, and the secondary air temperature at the furnace increased from 199 °C in the pre transformation survey test to 350 °C. The three coal mills operated smoothly and the combustion inside the furnace was stable. The actual effect of the flexibility transformation of the plant exceeded expectations.