烟气导流罩结构对小型锅炉NO_x排放特性的影响

为了满足小型锅炉更严格的排放标准,用数值模拟方法研究了一种能有效降低NO_x排放的环形烟气导流罩,具体研究了其结构参数对燃气锅炉炉内速度、温度分布和炉膛出口NO_x排放浓度的影响。结果表明:烟气在炉内循环并可连续地被卷吸到环形烟气导流罩内,使炉内的对流传热效果增强,平均温度降低,NO_x排放急剧减少。当导流罩长度L=80 mm,间隙h=20 mm,半径R=42.5 mm时,炉膛出口NO_x浓度最低且燃烧反应完全,为适合该小型锅炉的最佳尺寸。

Influence of Flue Gas Guide Structure on NOx Emission Characteristics of Small Boilers

To meet the coming,more stringent Nox emission standards for small boilers,the numerical simulation method is used to analyze the influence of the structure parameters on a simple structure named "circular gas guide",including speed,temperature distribution and furnace outlet concentration of Nox emission.The simulation results show that the flue gas circulates in the furnace and can continuously be sucked into the guide to enhance the convective heat transfer effect,decrease the average temperature and reduce the Nox emission.And when the guide length L=80 mm,gap h=5 mm,radius R=47.5 mm,the Nox concentration in the outlet of furnace is the lowest and the combustion reaction completely,which is the best size for the small boiler.