Abstract
Hydrogen separation through palladium-based membranes is one of the most promising technologies to produce H2 gas. The main purpose of this work is to comprehensively study the impact of different parameters on hydrogen diffusion flux (JH2) through a Pd–Ag membrane. The effect of implementing sweep gas on JH2 is investigated along with two methods of applying pressure difference, namely pressurized method, and vacuum method. Also, the effect of species mole fraction for three binary mixtures (H2/N2, H2/CO2, and H2/CO) is examined. A CFD model is developed and used to perform the study. Experimental data from the literature are used to validate the CFD model, and the results showed good agreement with the experimental data. The results revealed that implementing sweep-gas could significantly improve the hydrogen diffusion flux (by 25%) at the law-pressure difference. Moreover, it turns out that the vacuum method is more effective than the pressurized method, where it results in JH2 greater than the pressurized method by 15–36%. Furthermore, the CFD results showed that more hydrogen gas can be extracted from a binary mixture of H2/N2 (0.93 mol/m2.s) than of CO (0.90 mol/m2.s) and H2/CO2 (0.81 mol/m2.s).
•CFD model is developed to investigate H2 separation through Pd-based membrane.•Effects of operational parameters on hydrogen diffusion flux are studied.•Pressurized feeding gas and vacuum permeation methods are compared.•Sweep-gas boosts the H2 diffusion driving force by lowering partial pressure of H2.•More hydrogen can be extracted form H2/N2 mixture, followed by H2/CO, then H2/CO2.