不同空气稀释剂对合成气扩散火焰NOx生成特性的影响  

Effects of Different Air Diluents on NO_x Formation in Counterflow Syngas Diffusion Flames

作　　者：汤根土[1] 吕俊复[1] 岳光溪[1] 张海[1] 

机构地区：[1]清华大学热能工程系,热科学与动力工程教育部重点实验室,北京100084

出　　处：《动力工程》2008年第6期924-930,共7页Power Engineering

基　　金：中国博士后基金资助项目;国家自然科学基金资助项目(50576041)

摘　　要：针对合成气燃烧中NOx的生成机理,以结构简单的对冲火焰作为研究对象,利用化学反应动力学模型研究了不同稀释剂对火焰特性、自由基浓度及NOx生成的影响.结果表明:3种稀释剂降低NO排放效果的顺序为:CO2>H2O>N2,少量的CO2或H2O稀释空气时能有效地降低NOx排放;稀释剂量的增加对合成气中是否存在CH4时的影响趋势基本一致;合成气中CH4的存在降低了火焰温度和热力型NO生成,促进了快速型NO的生成;火焰拉伸率的提高使火焰温度和NO的生成降低.说明采用CO2和H2O稀释空气能有效抑制NOx的生成.Based on NOx formation mechanism in syngas combustion, taking the simple structured counterflow flame as the object of study, the effects of different diluents on flame characteristics, free radical concentration and NOx formation were investigated by using models of detail chemical-kinetic mechanism. Results show that, in reducing NOx emission, CO2 appears to be most effective, followed by H2O, and then N2. NOx emission can effectively be reduced by diluting the air with a small amount of CO2 or H2O. Existance of CH4 in syngas has little influence on diluents in reducing NOx emission, but reduces the flame temperature and thermal NO formation, and promotes prompt NO formation. The flame temperature and NO formation can be reduced by increasing the flame strain rate. Therefore, CO2 and H2O diluting air can effectively inhibit NO, formation.

关 键 词：环境科学 合成气 扩散火焰 NOx 排放特性 稀释剂 

分 类 号：X511[环境科学与工程—环境工程]