CH_4,CO_2,CO对钯复合膜透氢性能的影响

Effects of Methane,Carbon Dioxide and Carbon Monoxide on Hydrogen Permeation Through Pd Composite Membrane

采用化学镀法制备了钯复合膜。在200～450℃下，恒定H2进气量和总进气量，以N2为平衡气，H2-N2混合气为参比气，考察了不同含量的CH4，CO2，CO对钯复合膜透氢性能的影响。实验结果表明，对钯复合膜的透氢性能，CH4几乎没有影响，C02的影响较小（透氢量的降低率小于5％），CO的影响最大。体积组成为98％H2—2％CO的混合气，在300℃时钯复合膜透氰速率下降幅度明显增大。用扫描电子显微镜、X射线能谱仪、X射线衍射仪对透氢后的钯复合膜进行表征，表征结果显示，钯复合膜表面有少量积碳，说明在钯复合膜表面上发生了CO的歧化反应。

Pd composite membrane was prepared by electroless -plating on ceramic tube. Effects of CH4, CO2 and CO in feed gas on hydrogen permeation through the Pd composite membrane were investigated under constant flowrates of total feed gas and hydrogen, with N2 as balance gas and H2 - N2 mixed gas as reference gas in the range of 200 - 450 ℃. The effect of CH4 on hydrogen permeation is negligible. The effect of CO2 on hydrogen permeation is lesser（ decrease of hydrogen permeation rate is less than 5% ）. CO in feed gas obviously inhibits hydrogen permeation. The negative effect of CO is serious below 300 ℃ with 98% H2 -2% CO（ volume fraction） as feed gas. Trace amount of carbon deposition was found on the surface of Pd composite membrane by means of SEM, EDS and XRD, which indicates that CO disproportionation occurs on Pd composite membrane surface.