旋转滑动弧氩等离子体裂解甲烷制氢

Rotating gliding arc plasma assisted hydrogen production from methane decomposition in argon

采用切向气流和磁场协同驱动的旋转滑动弧氩等离子体,先通过光谱分析法计算了其电子温度和电子密度,了解其物理特性,将其应用于甲烷裂解制氢,研究了进气流量和CH_4/Ar比对反应效果的影响。结果表明,该滑动弧系统电子温度为1.0-2.0 e V,电子密度高达1015cm^(-3),是介于热与低温等离子体之间的一种等离子体形式,具有独特的物理特性,可以在达到较高反应效率的同时,保持较大的处理量;在CH_4裂解制氢实验中,CH_4转化率可达22.1%-70.2%,并随进气流量和CH_4/Ar比的增大均逐渐降低;H_2选择性为21.2%-61.2%,并随进气流量的增大先基本不变后有所增大,随CH_4/Ar比的增大逐渐降低;与应用于甲烷裂解的不同形式的低温等离子体对比(如微波、射频、介质阻挡放电等)可以发现,旋转滑动弧在获得较高甲烷转化率、较高H_2选择性和较低制氢能耗的同时,还可以保持较大的处理量,即进气流量可达6-20 L/min。

A kind of rotating gliding arc（ RGA） argon plasma co-driven by tangential flowand magnetic field was investigated and used for hydrogen production from methane decomposition. In order to obtain insights into the physical characteristics of the RGA plasma,optical emission spectroscopy（ OES） analysis was used to determine the electron temperature and electron density. In addition,the effects of feed flowrate and CH4/ Ar ratio on the performance of the methane decomposition process in this RGA plasma were also investigated.Results have shown that,the RGA plasma is a kind of unique plasma between thermal and non-thermal plasma,with electron temperature of 1. 0-2. 0 e V and electron density of 1015cm-3. In this system,the CH4 conversion could be 22. 1%-70. 2% and it increased with the increase of flowrate or CH4/ Ar ratio. The H2 selectivity varied from 21. 2% to 61. 2%,and with the augment of flowrate,the H2 selectivity first varied slightly and then increased. A comparison of different non-thermal plasmas（ e. g.,microwave,radio frequency,and dielectric barrier discharge） showed that the RGA plasma could provide a relatively high CH4 conversion and H2 selectivity,as well as a relatively lowenergy consumption for H2 production,while maintaining a high flowrate（ i. e.,processing capacity） of 6-20 L /min.