粒径对贫煤空气分级NO_(x)排放特性影响的试验研究  

Experimental Study on the Effect of Coal Particle Sizes on NO_(x) Emission Characteristics of Lean Coal Under Air-staged Combustion Conditions

作　　者：王勇强 陆方[1] 周月桂[1] WANG Yongqiang;LU Fang;ZHOU Yuegui(Institute of Thermal Energy Engineering,School of Mechanical Engineering,Shanghai Jiao Tong University,Shanghai 200240,China)

机构地区：[1]上海交通大学机械与动力工程学院,热能工程研究所,上海200240

出　　处：《动力工程学报》2021年第11期926-932,共7页Journal of Chinese Society of Power Engineering

基　　金：国家重点研发计划资助项目(2016YFB0600701)。

摘　　要：采用煤粉燃烧自维持一维试验炉进行了不同煤粉粒径贫煤的单级和多级空气分级燃烧试验,研究了煤粉粒径对煤粉空气分级燃烧NO_(x)排放的影响,探索适用于贫煤空气分级燃烧的煤粉粒径参数和分级级数,以实现较低的NO_(x)排放。结果表明:粒径影响炉内煤粉颗粒燃烧过程和NO_(x)生成特性,细煤粉颗粒的燃烧速率更快,在炉内易形成还原性气氛,有利于抑制NO_(x)生成和促进已生成的NO_(x)的均相异相还原反应;在深度空气分级燃烧条件下,粒径减小对于降低NO_(x)排放的作用更加显著;采用多级空气分级燃烧能够进一步降低NO_(x)排放量。建议在实际燃用贫煤的锅炉中,采用两级空气分级燃烧和平均粒径为22.78μm的细煤粉相结合的燃烧技术方案,此时NO_(x)质量浓度可减少27.9%。Single and multi air-staged combustion of lean coal with different particle sizes were carried out in one-dimensional self-sustained pulverized coal combustion experimental furnace.The influence of particle sizes on the NO_(x)emission of lean coal under air-staged combustion was detailedly investigated to explore the appropriate particle size and air-staged number to realize lower NO_(x)emission for lean coal combustion.Results show that the particle size affects the pulverized coal combustion process and NO_(x)formation characteristics in the furnace.The combustion rate of pulverized coal with fine particle size is faster to form a reducing atmosphere in the furnace,which can inhibit the NO_(x)formation and promote the homogeneous and heterogeneous reduction reaction of the formed NO_(x).Under the deep air staged combustion condition,the effect of particle size reduction on NO_(x)emission is more significant.Moreover,multiple air-staged combustion can be used to further reduce NO_(x)emission.The combustion technology scheme combining double air-staged combustion and the fine mean particle size of pulverized coal with 22.78μm can be adopted in the actual boilers using lean coal,the NO_(x)emission can be reduced by27.9%.

关 键 词：煤粉燃烧 贫煤 空气分级燃烧 粒径 NO_(x)排放 

分 类 号：TK227.1[动力工程及工程热物理—动力机械及工程]