Abstract
Numerical simulations of combustion optimization under multi-operating modes have been performed for a 600 MW tangentially coal-fired super-critical boiler. Under rated boiler load, the computational combustion efficiency of pulverized coal of 99.5% and nitrogen oxides (NOx) emission less than 400 mg/Nm^3 (6% O_2) agree well with the experimental data. For the high combustion efficiency of pulverized coal and low NOx emission, some combustion optimization information should be conducted as follows: (1) A double V-shaped (DV) secondary air distribution mode and more under fire air (UFA) are recommended. (2) The air flow of separated over fire air (SOFA) is not less than 75% of designed value. (3) The tilting angle of SOFA burner in horizontal direction is bigger than zero degree. (4) Under the load of 450MW, the lowest four primary air burner nozzle layers are recommended to be in service. (5) Under the load of 300MW, the intermediate three primary air burner nozzle layers are recommended to be in operation.
