The low nitrogen combustion technology of pulverized coal pre - combustion can balance stable combustion and NO emission control,which has great application potential in the field of flexible peak shaving and stable combustion of coal-fired boilers. Based onthe 5 MW combustion test rig,the operation performance of a high-concentration pulverized coal pre-combustion low-nitrogen burner witha small pre-combustion chamber developed by the authors′ team was studied. The effects of primary air rate,internal and external secondary air distribution and separate over-fire air (SOFA) on the combustion performance and pollutant emission of the burner were systematically studied by CFD numerical simulation. The combustion model was verified by the test results of the 5 MW combustion test rig.The maximum deviation between the actual temperature and the numerical calculation results is 44 ℃ ,and the error range is ±3.3%,whichproves the accuracy of the selected combustion model. The results show that the primary air rate is the key factor affecting the backflowzone of the pre-combustion chamber,and too low or too high primary air rate will affect the combustion stability and nitrogen reductionability respectively. Under the condition of 8.8% primary air rate,sufficient backflow can be guaranteed,which is conducive to the ignitionand emission control of pulverized coal. Increasing the internal secondary air rate can entrain more high-temperature flue gas in the furnace,which is conducive to the burning of pulverized coal. However,the increase of the high-temperature oxidizing atmosphere area in thefurnace will lead to the increase of pollutant emission. The internal secondary air rate of about 43.5% can both stabilize combustion and reduce nitrogen. Replacing the external secondary air with an appropriate proportion of SOFA can make the nitrogen-containing compoundsin the combustion area more easily reduced,thus reducing emissions. At 23% SOFA rate,a significant nitrogen reduction effect was observed,with NO emissions of 72 mg/ m(6% O),a reduction of about 67% compared to 0% SOFA rate.

周旭(1986—),男,山西吕梁人,高级工程师,硕士。E-mail:275561920@qq.com

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ZHOU Xu,ZHANG Hanlin, ZHANG Feng, et al. Optimization of air distribution of high concentration pulverized coalpre-combustion strong stable combustion low nitrogen burner[J].Clean Coal Technology,2024,30(9):43-51.