To achieve the requirements for ultra-low emission

the technology idea of low NO_x emission based on superfine pulverized coal reburning is put forward for a 1 000 MW swirl combustion boiler manufactured by Dong Fang Boiler Group Co.

Ltd. Based on the CFD software platform

the combustion situation in the furnace and the characteristics of NO_x emission are simulated numerically in total 10 cases which are in different superfine pulverized coal reburning situations. The influences of the excess air ratios in main combustion zone and reburning zone

the injection method of reburning fuel

and the ratio of primary and secondary air are analyzed. The results show that

when the top burners on both sides are changed into reburning fuel nozzles

the excess air ratios in main combustion zone and reburning zone are 1.0 and 0.8

respectively

the ratio of the primary air to secondary air maintains the designed value

it can obtain a better effect of NO_x removal. The concentration of NO_x at the furnace exit is reduced to 247.4 mg/m3 which is about 18% lower than 300 mg/m3 in the existing design scheme. These results prove that the superfine pulverized coal reburning is effective to reduce the NO_x emission from large capacity opposite coal-fired boilers.