多孔陶瓷板催化燃烧炉窑特性研究

Study on Characteristics of Porous Ceramic Plate Catalytic Combustion Furnace

基于催化堇青石蜂窝陶瓷板研制完全预混循环水冷燃烧器,应用于天然气催化燃烧炉窑系统。在炉门开启工况下,研究炉窑的一次点火升温曲线、陶瓷板表面温度分布及过剩空气系数对炉窑污染物排放的影响。在炉门关闭工况下,研究输入功率对炉窑污染物排放、辐射热流量、辐射效率的影响。燃烧器的一次点火升温经历气相燃烧—火焰吸附—缓慢升温—稳定燃烧4个阶段,通过选用适当热导率的多孔介质可以缩短燃烧器的点火升温时间。炉门开启阶段,随过剩空气系数增加,燃烧器壁面垂直温度梯度逐渐减小,催化陶瓷板表面平均温度先增后减,当过剩空气系数为2.0时,垂直温度梯度为0.3 K/cm,表面平均温度达到最大值973 K。炉门开启阶段,CO、NO_(x)体积分数随过剩空气系数增加而增大,当过剩空气系数为2.1时,CO、NO_(x)的最大体积分数分别为10×10^(-6)和14×10^(-6),CH_(4)体积分数始终为0。炉门关闭阶段,随着炉窑输入功率增加,CO、NO_(x)、CH_(4)体积分数逐渐降低,最大体积分数分别为12.9×10^(-6)、1.8×10^(-6)、14.9×10^(-6),当炉窑达到最大输入功率4.5 kW时,三者体积分数均为0。炉门关闭阶段,随着炉窑输入功率增加,辐射热流量增加,辐射效率降低,当达到最大输入功率4.5 kW时,辐射热流量和辐射效率分别为1347.67 W和0.30。

Based on catalytic cordierite honeycomb ceramic plate,a fully premixed circulating water-cooled burner was developed and applied to natural gas catalytic combustion furnace system.The effects of the primary ignition heating curve of the furnace,the surface temperature distribution of ceramic plate and the excess air coefficient on the pollutant emission of the furnace were studied under the condition of furnace door opening.The influence of input power on pollutant emission of the furnace,radiation heat flow and radiation efficiency was studied under the condition of furnace door closing.The primary ignition heating of the burner goes through four stages:gas phase combustion-flame adsorption-slow heating-stable combustion.The ignition heating time of the burner can be shortened by selecting porous media with appropriate thermal conductivity.In the opening stage of furnace door,the vertical temperature gradient of the burner wall gradually decreases with the increase of excess air coefficient,and the average temperature of catalytic ceramic plate first increases and then decreases.When the excess air coefficient is 2.0,the vertical temperature gradient is 0.3 K/cm,and the average surface temperature reaches the maximum value of 973 K.In the opening stage of furnace door,the volume fractions of CO and NO_(x)increase with the increase of excess air coefficient.When the excess air coefficient is 2.1,the maximum volume fractions of CO and NO_(x) are 10×10^(-6)and 14×10^(-6),respectively,and the volume fraction of CH_(4) is always 0.In the closing stage of furnace door,the volume fractions of CO,NO_(x) and CH_(4) gradually decrease with the increase of input power of the furnace,and the maximum volume fractions are 12.9×10^(-6),1.8×10^(-6)and 14.9×10^(-6),respectively.When the furnace reaches the maximum input power of 4.5 kW,the volume fractions of all three are 0.In the closing stage of furnace door,with the increase of input power of the furnace,the radiation heat flow increases and the radiation efficiency decreases.When the maximum input power of 4.5 kW is reached,the radiation heat flow and radiation efficiency are 1347.67 W and 0.30,respectively.