一次风率及循环废气率变化对燃油锅炉运行中氮氧化物生成的影响

Influences of First Stage Air Ratio and Gas Recirculation Ratio on the Generation of NO_x During Combustion by Oil Boiler

研究空气分级和废气循环燃烧等方式对油燃烧中NOx 生成的影响。实验发现 :分级燃烧对于燃料氮的转化有抑制作用 ,而且对含氮量较高的油燃料效果较明显 ,不论燃烧器功率如何 ,降低一次风率总使得NOx 的生成量减少 ;当一次风率占总过量空气系数的 50 %左右时 ,燃料氮的转化率存在一个最小值 ,而后随着一次风率的提高而增大并趋于一常数 ;增加废气循环率能降低油燃烧中NOx 的生成量 ,而且对于含氮量较低的油效果较明显 ,随着废气循环率增加 ,NOx 生成量的降幅趋缓并带来火焰稳定问题 ,因此存在有一个最佳废气循环率 ;废气循环燃烧会增大燃料氮的转化率 。

This paper studies the effect of air stage and gas recirculation combustion technique on the formation of NO x by burning oil. It shows from a experiment that:The air-stage combustion technique do have a e vident effect on controlling the generation of NO x converting from fuel-N ,especially for these oil with high Fuel-N content;and the NO x produ ction decreases with the lower of the first air ratio in any burner power. The fuel-N conversion ratio in creases when the first air ratio goes up and then te nd to a constant;a minimum fuel-N conversion ratio exists when the first air r atio lay nearly the half of the total excess air ratio; During oil combustion ,the NO x generation can be reduced through rising the gas recirculation r atio,especially for those oil with low Fuel-N content;with the increase of ga s recirculation ratio,the NO x reduction tends to small and the flame beco mes unstable; The gas recirculation combustion brings to a rising of the Fuel- N conversion ratio,especially when the first stage air ratio is lower.