Permeation characteristics of hydrogen through palladium membranes in binary and ternary gas mixtures

Abstract

The permeances of two palladium (Pd) membranes in pure H2, binary and ternary gas mixtures are investigated experimentally. With 10% of gas impurities (N2, CO2, or CO) in H2, the profiles of dimensionless permeance suggest that H2 permeation rate is lessened by approximately 50% to 90%, and the permeance reduced by the gas impurities is ranked as CO > CO2 > N2. By introducing a parameter of permeance resistance, which is the reciprocal of permeance, the permeance resistance in a ternary gas mixture can be predicted from the summation of individual permeance resistances in binary gas mixtures, revealing no synergistic effect exhibited from the interaction of contaminants. At least 75% and up to 100% of H2 in the gas mixtures can be recovered in the membrane system, and the maximum H2 recovery develops at the H2 partial pressure difference of 2 or 3 atm. In the Arrhenius-type equation describing the relationship between the permeance and temperature, the activation energy is between approximately 2 and 18 kJ mole−1. In general, the permeances of the membranes in gas mixtures, especially in ternary gas mixtures, are more sensitive to temperature when compared with those in pure H2, stemming from lower activation energy exhibited. Copyright © 2017 John Wiley & Sons, Ltd.