In order to study the combustion process and NO_x emission of supercritical 350 MW unit boilers

the Fluent software was applied to carry out numerical simulation on a 350 MW tangentially coal-fired boiler.The aerodynamic field

temperature field

component field and the NOxdistribution under variable load operation were analyzed.The simulation results indicate that

the tangential circle can be seen obviously and the aerodynamic field is swirling from bottom to top in the furnace.The temperature reaches the highest around the burner areas

it decreases with the increasing furnace height.The temperature difference in the burner zone is 352 Kfrom the BMCR condition to the 30% THA condition.At 30% THA condition

the temperature level in the furnace is low

so the ignition and combustion stabilization need to be considered.The component field is strongly related to the temperature field

the high temperature area corresponds to high CO and low CO_2 concentration.NOxis generated in great quantities in the highest temperature field.The NOxconcentration at the furnace outlet decreases gradually with the unit load.