Study on thermal load test of water wall of 350MW supercritical circulating fluidized bed boiler

Abstract

The thermal load distribution of water wall is the key parameter for the structural design of water walls in supercritical and ultra-supercritical circulating fluidized bed boiler (CFB). In this paper, the temperature distribution of the water wall of a 350MW supercritical CFB boiler under typical working conditions was measured by installing 118 temperature measuring points at the back-fire water wall tube and adjacent fins. The deviation in the heat load of water wall as a function of furnace height, width and depth was obtained as well. The experimental results show that temperature of the working medium in water-wall tube increases with increasing furnace height. The thermal deviation of the steam temperature in water wall tube in the direction of furnace width and depth is large at the initial boiler start-up period, the transition period from dry to wet state, and the low load condition. Despite these, the heat load distribution of water wall at the same furnace height remains the same. The results provide a reference for the structural design and operation optimization of supercritical and ultra-supercritical CFB boiler.