针对600MW超临界W火焰锅炉，通过数值模拟的方法研究了煤粉浓度和燃烬风对劣质无烟煤燃烧NOx释放特性的影响。结果表明，NOx主要在煤粉燃烧前期距一次风喷口2～4m处大量生成，选择合适的煤粉浓度，炉内NOx最大值可下降16．5％；与常规浓度相比，高浓度煤粉燃烧可有效降低炉膛出口NOx排放；燃烬风对炉内各物质含量及NOx的生成影响显著，燃烬风率由6％增加到15％，炉膛出口NOx排放量由756．0mg／m3下降到502．9mg／m3。%In light of a 600 MW supercritical pressure W-flame boiler, the NOx release characteristics during the com- bustion of poor-quality anthracite were numerically simulated at the conditions of different pulverized coal concentra- tions and different over-fire air rates. The results indicate that a large quantity of NOx is generated in the initial burning stage of pulverized coal, at the distance of 2 - 4 m away from the primary air nozzles. The maximum of NOx in the fur- nace can be reduced by 16.5% by choosing a reasonable pulverized coal concentration. Compared with the conven- tional concentration, NOx emissions at furnace exit can be effectively reduced during the combustion of pulverized coal with higher concentration. Over-fire air has great effects on the substance contents and the generation of NOx in the fur- nace, NOx emissions at furnace exit decrease from 756. 0 mg/m3 to 502.9 mg/m3 with the rate of over-fire air increas- ing from 6% to 15%.
展开▼
