介质阻挡放电脱除NO_x反应器的评价方法及运行流量特性分析

An Evaluation Method of Dielectric Barrier Discharge Reactors for NO_x Removal and Characteristics Analysis of Gas Flow Rate

将气体放电生成非热平衡等离子体过程从撞击时刻起分为前后2阶段,指出放电反应器的性能优劣主要与撞击前的阶段相关。原因是撞击前是等离子反应器产生高能电子的阶段,而撞击后是非热平衡等离子体发生化学反应的阶段。对NO和N2体系的气体放电过程进行化学反应动力学和电子碰撞动力学分析,指出利用该体系可以得到放电反应器产生高能电子的平均动能,实现反应器性能优劣的评价。进行不同气体流量下,同轴介质阻挡放电脱除氮氧化物的实验研究。研究结果表明,在注入能量密度基本相同的情况下,气体流量的变化对NO的脱除效果影响甚微。对实验中采用的反应器进行了评价计算,结果表明,反应器出口NO浓度为150～250mL/m3的所有试验点的高能电子平均动能均为3～3.5eV。

Non-thermal plasma discharge process was divided into two phases according to the collision moment. Before the collision energetic electrons are produced and accelerated under the influence of an electric field, after the collision intimate mixtures of the electrons, radicals, ions and molecules react at relatively low gas temperatures. It is pointed out that the quality of various reactors is mainly dependent upon the former phase. The electron and chemical kinetic process of dilute concentrations of NO in N2 was analyzed. Analysis results indicate that by measuring the concentration of NO as a function of input energy density, it provides a measure of the electron mean energy in the plasma. An electron mean energy in the plasma is possible to determine the quality of various reactors. An experimental study on the effect of gas flow rate on nitrogen oxides removal efficiency was conducted in a benchtop concentric cylinder dielectric barrier discharge reactor. Experimental results show that gas flow rate has little influence on nitrogen oxides removal efficiency when the input energy density is identical. The evaluation calculations show that the experimental data presented in this paper all correspond to an electron mean energy between 3.0 and 3,5 eV.