Experimental Study and Optimization Analysis of Ultra-supercritical Boiler Combustion Adjustment Based on Temperature Field in Furnace

Due to the uneven distribution of combustion temperature field in the operation processes of thermal power plants, issues such as over-temperature, tube explosion and flue gas corridor of the furnace heating surfaces may occur. By evaluating the temperature field distribution of the boiler during operation processes, the combustion adjustment can be made to improve the safety, stability and economy of the boiler operation when the operation status can be examined timely. With the boiler of a 660 MW ultra-supercritical power plant as an example, the combustion optimization adjustment test and simulation were carried out. Temperature of heating surfaces and the wall temperature change at the burner were analyzed, and the wind speed and pulverized coal concentration deviations of powder pipes in the pulverizing system, internal and external secondary air volume and intensity of the burner, the adjustment of the direct current air volume, and the wall air in the furnace were measured. Results show that the factors, such as the combination operation modes of different coal mills and the modes of secondary air distribution have a great impact on the boiler operation. In particular, the wall over-temperature, the burner temperature and reducing atmosphere on the heating surface are influenced, which will affect the boiler economic operation. After adjustment, the wall over-temperature phenomenon of the screen superheater, high temperature superheater and high temperature reheater disappears, there is no burnout of burners, and the amount of NO_x generation is also within a reasonable range.