Abstract:Taking the early PC utility boiler as examples, an operating mode of optimizing air distribution in furnace is put forward to lower NO _Xemission. It has the advantage of simply operation and low cost. The experimental result shows that NO _Xemissions will increase with the total air rate, however, the economy of the boiler decreases, so the total air rate must take consideration of both the economy and NO _Xemissions of the boiler. Under the constant total air rate, optimizing the secondary air and over fire air may further decrease NO _xemissions with the lower secondary air rate in the middle of burners and the larger secondary air rate in upper and lower layers in burners. Under the premise of constant secondary air ratio, NO _Xemissions decrease with increasing the over fire air ratio. The operating mode in this paper can effectively decrease NO _Xemissions from 908 mg/m ³to 790 mg/m ³.