摘要
放电等离子体结合选择催化还原脱除NOx是一项很有前景的贫燃尾气治理技术,其预处理过程中,尾气中NO会向NO2转化。为了解重要的活性中间产物O3的作用和生成特性以及常见的烃类添加剂C2H4的作用,在介质阻挡放电等离子体反应器内进行了相关实验研究。监测N2/O2,N2/O2/NO,N2/O2/C2H4,N2/O2/NO/C2H4共4个体系下的O3产生特性,并通过N2/O2/NO和N2/O2/NO/C2H4体系的比较考察C2H4对NO转化影响的结果表明:除N2/O2体系外,其它体系中都不会产生大量的O3;C2H4不但提高了NO的转化率,还明显地抑制放电过程NO的生成。可以推断,O3作为氧化剂能促进NO向NO2的转化,C2H4添加剂可以提高NO的转化率。
Plasma-facilitated selective catalytic reduction of NOx is one of promising after-treatment methods for lean-burn exhaust, which could overcome the disadvantages of the conventional three way catalyst method in rich oxygen condition at low temperature(〈300℃). This method could be divided into plasma process and catalysis process. It has been reported that ozone is a key intermediate among the products of plasma, and hydrocarbon is a common additive for this process. So in this experiment, characteristics of ozone produced and C2 H4 effects were necessary to study in N2/O2, N2/O2/NO, N2/O2/C2H4 , and N2/O2/NO/C2 H4 systems, for the sake of discussing the related chemical reactions mechanism. Results showed that in N2/O2 mixture a large amount of ozone produced was observed, but in other gas systems, no more than 20×10^-6 ozone was generated. NO oxidation took place with the plasma applied, and the addition of ethylene increased the oxidation up to 35 % in the experimental range. And in N2/O2 and N2/O2/C2 H4 systems, it was found that ethylene additive could greatly restrict the formation of nitrogen oxides in the discharge. Finally two conclusions were made: ozone served as an important oxidizer in NO to NO2 conversion, and ethylene could enhance the conversion of NO to NO2.
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2008年第1期103-106,共4页
High Voltage Engineering
基金
国家自然科学基金重点项目(50537020,50777034)
中国博士后科学基金(20060390453)
广东省自然科学基金(06301239)
深圳市科技计划项目(B-95).