DBD结构对船用LNG发动机尾气CH_(4)氧化脱除的影响  

Effect of DBD structure on oxidative removal of CH_(4) from marine LNG engine exhaust

作　　者：李宏玉 蔡云凯 祝能 相闯 蒋顺豪 吕林[1] LI Hongyu;CAI Yunkai;ZHU Neng;XIANG Chuang;JIANG shunhao;LYU Lin(School of Naval Architecture,Ocean and Energy Power Engineering,Wuhan University of Technology,Wuhan 430063,China;School of Automotive and Transportation Engineering,Wuhan University of Science and Technology,Wuhan 430081,China;Weichai Power Co.,Ltd.,Weifang 261061,China)

机构地区：[1]武汉理工大学船海与能源动力工程学院,武汉430063 [2]武汉科技大学汽车与交通工程学院,武汉430081 [3]潍柴动力股份有限公司,潍坊261061

出　　处：《环境工程学报》2023年第6期1886-1896,共11页Chinese Journal of Environmental Engineering

基　　金：国家重点研发计划项目(2019YFE0104600)。

摘　　要：为提高等离子体氧化CH_(4)的脱除效率,同时避免放电过程中副产物NO_(x)的生成,在模拟天然气(LNG)发动机排气中,研究了介质阻挡放电(DBD)反应器电极结构参数对CH_(4)脱除效率、CO_(2)选择性及NO_(x)生成的影响及其机理。结果表明:增大电极直径使得气隙中折合场强E/N提高,增加了·O和·OH自由基的生成,促进了CH_(4)的氧化,提高了CO_(2)选择性;内电极直径的增大使E/N在气隙中分布更加集中,抑制了N_(2)(X,v)和N自由基的生成,减少了副反应的发生。与圆杆电极相比,螺纹电极的螺牙顶部附近具有过高的电场强度,从而促进N自由基的生成并抑制·O自由基的产生,故圆杆电极比螺纹电极具有更高的CH_(4)脱除效率及更低的NO_(x)生成。电极长度过长降低了折合场强以及电子平均能量,不利于氧化性活性粒子生成,导致CH_(4)脱除效率和CO_(2)选择性降低,同时增加了N_(2)(X,v),也使得NO_(x)增加。本研究可为提高低温等离子体协同催化剂促进甲烷还原NO_(x)系统的脱除效率,降低DBD反应器能耗提高能源利用率提供参考。In order to improve the removal efficiency of CH_(4) by plasma and avoid the generation of the byproduct—NO_(x),the influence of electrode structure parameters in the dielectric barrier discharge(DBD) reactor on CH_(4) removal efficiency and NOx generation,and its mechanism were studied under simulated liquified natural gas(LNG) engine exhaust.The results showed that the reduced field strength(E/N) in the air gap increased with the increase of inner electrode diameter.And the increase of E/N increased the formation of O and OH radicals,promoted the oxidation of CH_4,and improved the CO_(2) selectivity;At the same time,the increase of the inner electrode diameter made the distribution of E/N more concentrated in the air gap,inhibited the formation of N_(2)(X,v) and N radicals,and reduced the occurrence of side reactions.Compared with the round rod electrode,the screw electrode had a higher electric field strength near the top of the thread,which promoted the generation of N free radicals and inhibited the generation of O free radicals.Therefore,the round rod electrode had a higher CH_(4) removal efficiency and lower NOx generation than the screw electrode.Excessive electrode length reduced the converted field strength and the average electron energy,which was not conducive to the generation of active particles,leading to the reduction of CH_(4) removal efficiency,the reduction of CO_(2) selectivity and the increase of NO_(x).

关 键 词：等离子体 DBD 结构参数 CH_(4)氧化脱除 NO_(x)生成 

分 类 号：X511[环境科学与工程—环境工程]