Concentration polarization in Pd based membrane for the separation of H₂/He

Based on the current ITER design, there will be 12% inert gases in the off-gases from the torus collected in the cryopumps. The concentration polarization existing in the Pd membraneseparation processes could seriously affect the processes. In this work, the concentration polarization phenomenon in a porous ceramic supported Pd-based membrane for the separation of H2/He has been studied. A polarization coefficient was defined to describe the extent of the concentration polarization phenomenon, the effect of operation parameters such as operation pressure, upstream He molar fraction, and feed gas flow rate on the coefficient were investigated. The results show that the degree of inhibition by concentration polarization in hydrogen permeation decreases with increasing feed gas flow rate, whereas increases with rising He molar fraction and upstream total pressure.