TEST AND STUDY ON INFLUENCE OF PULVERIZED COAL PARTICLE SIZE UPON PERFORMANCE OF NO_x EMISSION FOR PULVERIZED COAL COMBUSTION

The regularity of NO_x emission performance along with coal sort, excess air ratio and temperature variation during combustion of different particle size for pulverized coal in onedimensional hotstate experimental furnace has been respectively studied. Results of study show that there is a critical value of pulverized coal particle size existing between NO_x emission concentration and the said particle size. When the said particle size to be smaller than the said critical value, the NO_x emission concentration to be reduced along with reduction of the particle size; when the particle size to be greater than the said critical value, the NO_x emission concentration to be increased along with the reduction of the particle size. After the pulverized coal being ultrafinely subdivided, the NO_x emission concentration for brown coal and bituminous coal is obviously reduced, but for lean coal and blind coal, the variation of NO_x emission concentration to be very small.