物理化学学报 >> 2005, Vol. 21 >> Issue (02): 192-196.doi: 10.3866/PKU.WHXB20050216

研究论文 上一篇    下一篇

介质阻挡放电引发氮氧化物等离子体化学反应

孙琪;朱爱民;牛金海;徐勇;宋志民   

  1. 大连理工大学化工学院等离子体物理化学实验室,大连 116024
  • 收稿日期:2004-06-09 修回日期:2004-10-08 发布日期:2005-02-15
  • 通讯作者: 孙琪 E-mail:labplpc@dlut.edu.cn

Plasma-induced Conversion of Nitrogen Oxides in a Dielectric Barrier Discharge Reactor

SUN Qi;ZHU Ai-Min;NIU Jin-Hai;XU Yong;SONG Zhi-Min   

  1. Laboratory of Plasma Physical Chemistry, Dalian University of Technology, Dalian 116024
  • Received:2004-06-09 Revised:2004-10-08 Published:2005-02-15
  • Contact: SUN Qi E-mail:labplpc@dlut.edu.cn

摘要: 在523 K介质阻挡放电条件下,研究了不同气体组分体系中NO的转化.实验表明,在无氧体系(NO/N2)中,转化的NO主要分解为N2和O2.在富氧(NO/O2/N2)条件下,由于NO和NO2的生成, NO的转化率最低.体系中加入C2H4(NO/C2H4/N2)时, NO转化率与NO/N2体系几乎一样,与NO相比,生成的O更易与C2H4作用,几乎没有NO2的生成.当C2H4和O2共存时(NO/O2/C2H4/N2),NO主要被氧化为NO2.当能量密度为125 J•L-1时, 与其它体系相比,NO/O2/C2H4/N2体系中NO转化率和NO2生成量最大,转化每个 NO分子能耗最小(61 eV).体系中C2H4主要被氧化为CO.四个体系中N2O的生成量都较少.讨论了介质阻挡放电条件下上述四个体系可能的反应机制.

关键词: 介质阻挡放电, 氮氧化物, 乙烯, 等离子体化学, 发射光谱

Abstract: In order to understand the mechanism of NOx removal in non-thermal plasma, the conversion of NO with different reacting gas mixtures under atmospheric pressure has been studied using dielectric barrier discharge plasma at 523 K. Experiments demonstrate that in the NO/N2 system, NO decomposition to N2 and O2 is in the majority. In the NO/O2/N2 system, NO conversion is the lowest for the formation of NO2 and NO. In the NO/C2H4/N2 system, NO is reduced to N2 at the same NO conversion as that in the NO/N2 system. Because the O atoms from NO decomposition are consumed more effectively by reaction of O and C2H4 than reaction of O and NO, NO2 formation is not observed. Dielectric barrier discharge is a very effective means for oxidizing NO to NO2 in the NO/O2/C2H4/N2 system. At the energy density of 125 J•L-1, NO conversion and concentration of NO2 formed in the NO/O2/C2H4/N2 system are the highest, the energy consumption is the lowest, 61 eV per converted NO molecule. C2H4 is mainly oxidized to CO in the dielectric barrier discharge plasma. A small amount of N2O is formed in the four systems. The in-situ optical emission spectra(200~900 nm) have also been investigated under atmospheric pressure at 523 K. The observations of N2 second positive band, NO γ-band and NO β-band with different gas mixtures imply that some excited-state active species from plasma-induced processes can effectively convert NO. Finally, mechanisms for the NO conversion in the four systems were proposed on the basis of experiment and relative literature.

Key words: Dielectric barrier discharge, NOx, C2H4, Plasma chemistry, Optical emission spectroscopy