Influence of Wall-SOFA on the Gas Temperature Deviation of a 660 MW Tangentially Coal-Fired Boiler

Abstract

A series of numerical simulations were conducted to study the influences of separated over-fire air (SOFA) distribution, yawing and tilting angles on the flue gas temperature deviation of a 660MW tangentially coal-fired boiler. The turbulent flow, combustion, pollutants and emission characteristics were investigated. The numerical model developed in the study was first validated with field test, which showed good consistence between the numerical and experimental results. Further study indicated that with the increase of SOFA rate, the coal burnout rate, temperature uniformity coefficient and temperature deviation on the temperature detection line (TDL) declined, and the NOx emission dropped. Increase the SOFA yawing angle in reverse tangential direction leads to reduction of high temperature region in the center of lower furnace exit section and in the left of upper furnace exit section, which is positive in reducing gas temperature deviation. Tilting SOFA nozzle upward leads to upward movement of high temperature region in the upper furnace burnout region, increases in gas temperature of upper and lower furnace exits, decreases in temperature distribution uniformity coefficient of furnace exit section and a slight decrease in coal burnout rate, which is negative for reducing gas temperature deviation. (CSPE)