摘要
在一维管式炉上进行高温下NH_(3)还原NO_(x)特性实验研究,并基于化学反应动力学模型对实验工况进行模拟计算,分析在近零氧工况下NH_(3)/NO_(x)反应过程中关键基元反应及主要活性基团变化规律,探究高温下氨还原NO_(x)反应机理。结果表明:在无氧或者氧气体积分数为0.1%工况时,反应温度窗口明显向高温偏移,NH_(3)/NO_(x)还原反应进行的拐点温度为1 100℃,反应过程中关键的基元反应为NH_(2)/NO_(x)还原反应,温度对这组基元反应的一阶敏感性系数决定了最佳反应温度窗口;OH与NH_(2)自由基是反应中重要的活性基团,其浓度的积累也影响反应温度窗口,无氧工况下最佳反应温度窗口为1 300~1 400℃;无氧工况下NH_(2)自由基主要由3条反应路径还原NO_(x),NH与NNH自由基是最重要的中间产物,而HNO的存在会造成NO_(x)质量浓度增加。
The NO_(x) reduction characteristics by NH_(3) at high temperature was studied experimentally in a one-dimensional tubular furnace,and the experimental conditions were simulated based on the chemical reaction kinetics model.The varieties of key elementary reactions and main active groups in the NH_(3)/NO_(x) reaction process under near zero oxygen conditions were analyzed,and the reaction mechanism of NO_(x) reduction by NH_(3) at high temperature was explored.The experimental results show that the reaction temperature window obviously shifts to high-temperature zone under anaerobic condition or when the oxygen volume fraction is 0.1%,and the inflection point temperature of NH_(3)/NO_(x) reduction reaction is 1100℃.The key elementary reaction in the reaction process is NH_(2)/NO_(x) reduction reaction,and the optimal reaction temperature window is determined by the influence of temperature on the first-order sensitivity coefficient of this group reactions;OH and NH_(2) free radical are important active groups in the reactions,and their concentration accumulation also affects the reaction temperature window.The optimum reaction temperature window under anaerobic condition is 1300 to 1400℃;under anaerobic conditions,NO_(x) is reduced by NH_(2) free radical mainly through three reaction paths,NH and NNH free radicals are the most important intermediates,and the presence of HNO will increase the NO_(x) emission mass concentration.
作者
毕德贵
杨柳
王敬燊
徐达
BI De-gui;YANG Liu;WANG Jing-shen;XU Da(School of Environment and Architecture,University of Shanghai for Science and Technology,Shanghai,China,Post Code:200093)
出处
《热能动力工程》
CAS
CSCD
北大核心
2023年第7期101-107,共7页
Journal of Engineering for Thermal Energy and Power
关键词
高温
基元反应
氧量
温度窗口
high temperature
elementary reaction
oxygen
temperature window
