Abstract Palladium membranes have been used for hydrogen purification for a long time due to their infinite selectivity and excellent permeation performance. However, a coexisting impurity gas, like CO, will inhibit the hydrogen permeation flux that results from the concentration polarization (CP) and competitive adsorption inhibition effects. This work aims to investigate the two inhibition effects separately and quantitatively under different temperatures and pressures. Therefore, permeation experiments of H2 (90%)/N2 (10% to 5%)/CO (0% to 5%) mixtures have been carried out at temperatures ranging from 623 to 698 K and H2 partial pressure drops from 30 to 100 kPa. The permeation of H2/N2 is used to study CP because the competitive adsorption of N2 can be ignored. Then, the further H2 flux reduction of xH2/(1-x-z)N2/zCO permeation relative to that of xH2/(1-x)N2 permeation can be attributed to the competitive adsorption of CO. The experimental results show that the CP effect would be enhanced by increasing temperature and pressure, while the CO competitive adsorption effect would be depressed. Meanwhile, the CO inhibition effect generally becomes smaller when the membrane thickness becomes thicker. Based on the results in this work, operation conditions are suggested to be at a higher temperature and higher pressure for a thicker Pd membrane in consideration of increasing the H2 permeation flux and reducing the CO adsorption effect. The experimental and calculation methods used in this work can provide a new way for investigating the inhibition effect on hydrogen permeation caused by other nonpermeable gases like CO2, Ar, or H2O.

中文翻译：

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CO对氢通过Pd/Al2O3复合膜渗透的抑制作用：浓度极化和竞争吸附作用的综合研究

摘要 钯膜因其无限的选择性和优异的渗透性能，长期以来一直用于氢气提纯。然而，共存的杂质气体，如 CO，会抑制由浓差极化 (CP) 和竞争吸附抑制效应引起的氢渗透通量。本工作旨在分别定量研究不同温度和压力下的两种抑制效果。因此，H2（90%）/N2（10% 至 5%）/CO（0% 至 5%）混合物的渗透实验在 623 至 698 K 的温度范围内进行，H2 分压从 30 降至 100千帕。H2/N2 的渗透用于研究 CP，因为 N2 的竞争吸附可以忽略不计。然后，与 xH2/(1-x)N2 渗透相比，xH2/(1-xz)N2/zCO 渗透的 H2 通量进一步降低可归因于 CO 的竞争吸附。 实验结果表明，CP 效应将是通过增加温度和压力而增强，而 CO 竞争吸附作用将被抑制。同时，当膜厚度变厚时，CO抑制作用通常会变小。基于这项工作的结果，考虑到增加 H2 渗透通量和降低 CO 吸附效果，建议操作条件为更厚的 Pd 膜在更高的温度和更高的压力下。