强电场中甲烷活化的汤生模型及反应动力学分析  

Townsend ionization model and kinetic analysis of methane activated in strong electric field

作　　者：李洁[1] 王彧婕[1] 龙华丽[1] 印永祥[1] 戴晓雁[1] 

机构地区：[1]四川大学化工学院,四川成都610065

出　　处：《化学工程》2007年第8期25-28,41,共5页Chemical Engineering(China)

基　　金：国家自然科学基金资助项目(10475060)

摘　　要：在强电场等离子体中,由于电子能量分布较大地偏离玻尔兹曼函数,文中采用汤生(Townsend)电离模型推导了平行电极介质势垒放电中高能电子碰撞使甲烷分子裂解为自由基的速率常数,得到了与放电电压相关联的自由基生成速率常数表达式。以选择的49个自由基反应为基础,对反应中生成的12种稳定分子和自由基的动力学行为进行了数值模拟。模拟得到的甲烷平衡转化率,C2烃收率和选择性较好地符合实验结果。在此基础上,进行了各反应对生成物贡献的动力学分析。分析表明甲烷转化主要依靠电子碰撞,C2烃生成是多种自由基反应共同作用的结果。同时指出了起主要作用的一些自由基反应。Because the distribution of electrons in strong electric field is departure from Boltzmann energy distribution, the rate constant of methane activated by energetic electrons in dielectric barrier discharge （DBD） was derived by Townsend ionization model and the expression of the rate constant related to the voltage of discharge was obtained. A kinetic simulation based on 49 free-radical reactions between 12 kinds of species was carried out. It presents that the simulation results agree well with the experiments. The kinetic analysis indicates that the decomposition of methane is mainly depended on the energetic electrons; the formation of C2 hydrocarbon is due to a couple of radical reactions. Some important radical reactions were given by the analysis.

关 键 词：DBD等离子体 反应动力学 甲烷活化 速率常数 强电场 C2烃 

分 类 号：O643.1[理学—物理化学]