To study the effect of wall separated over-fire air(SOFA)on flue gas temperature deviation,numerical simulation on furnace flow,combustion and pollutant emission under multiple loading conditions for a 660 MW tangentially coal-fired boiler was carried out.The effect of SOFA air rate and swinging angle onthe flue gas temperature deviation was investigated carefully.The simulation results indicate that increase of air rate of SOFA causes sectional temperature unevenness coefficient of smokestack at the furnac...