Separation of hydrogen gas from the outlet of water-gas shift reactor via palladium membrane was simulated with a two-dimensional computational fluid dynamic model. To study the influence of the geometry of membrane on the separation of hydrogen, four various membrane modules with cylindrical shells and cone tubes were considered. The results showed that the conical membrane module with upper and bottom diameters of 2 mm and 16 mm can potentially have the highest average flux across the other studied cases. To investigate the effect of flow pattern, four various flow patterns were applied to the model and it was found that the counter-current flow pattern has the highest flux across the membrane for the case in which the cross section is reduced along with the length of the membrane. The results also indicated that the change in the cross section of the membrane module can prevent the intensification of the concentration polarization index within the membrane. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.