Investigation on the heat transfer coefficient and uniformity in a polygonal furnace of a 350 MW supercritical CFB boiler

Abstract

The first international 350 MW supercritical circulating fluidized bed (CFB) boiler with a polygonal furnace was put into operation successfully in February 2018. The temperature profiles of the furnace water walls on four different heights, the temperature profiles near the outlets of the furnace water walls and dual-side water walls were measured under boiler loads of 50%, 75% and 100% BMCR, respectively. The coefficient and uniformity of heat transfer were investigated according to the test results. The results indicate that the temperature deviation of the furnace water walls on each layer at four different heights is no more than 6 °C, which illustrates the reliable hydrodynamic safety of the water walls of the polygonal furnace. Under boiler load of 100% BMCR, the temperature deviations of the front, rear, left and right water walls near the outlets of water walls are no more than 37 °C, and the temperature deviations of the 11 dual-side water walls are no more than 31.1 °C. As the boiler load increase from 50% BMCR to 100% BMCR, the average heat transfer coefficient of water walls increases from 98.1 W/(m2·oC) to 154.2 W/(m2·oC).