Due to its low volatile characteristics of lean coal

it is difficult to catch fire and burn out. Therefore

high temperature is needed to maintain combustion efficiency

while

this leads to high nitrogen oxide emission. For power plant boilers burning lean coal

stable combustion with lower nitrogen oxide emission is a challenging task. This study applied the 3D numerical simulation on the analysis of a novel de-coupling burner for low-volatile coal and its structure and operation parameters optimization. Results indicate that although it was more difficult for lean coal decoupling burner to ignite lean coal than high volatile coal

the burner formed a stepwise ignition trend

which promoted the rapid ignition of lean coal. Comparison of three central partition plate structure shows that in terms of characteristics of the flow field distribution

rich and lean separation and combustion

the structure with an inclination of 0° showed good performance

with its rich-lean air ratio being 0.85 and concentration ratio being 22.94

and there was an apparent decoupling combustion characteristic. Finally

the structure of the selected burner was optimized fo

r its operational conditions. The optimal operating parameters was determined as the primary air velocity of 24.9 m·s

-1

and the mass flow rate of pulverized coal of 2.5 kg·s

-1

in which the pyrolysis products were utilized as reductive agent more fully. Eventually

the nitrogen oxide was efficiently reduced to nitrogen

which emission concentration was 61.88% lower than that in the design condition.