A Model for Predicting the Permeation of Hydrogen-Deuterium-Inert Gas Mixtures through Palladium Tubes

Solubility of hydrogen and its isotopes in metals from mixed gases

“…Consequently, K will be approximately independent of isotope in metals [10] that do not have a strong affinity for hydrogen and that do not have microstructural sites that strongly trap hydrogen or its isotopes. On the other hand, a relatively small isotope effect on solubility has been reported in strong hydride formers such as palladium [3][4][5][6], as well as in stainless steel [1]. In order to keep our analysis general, we will therefore assume that K H 5 K D .…”

“…(6) is simple: isotopic exchange between H 2 and D 2 produces HD gas and thereby reduces the partial pressures of both H 2 and D 2 gases [10,12]. Hickman and others have not recognized the significance of the HD equilibrium [3][4][5][6][7][8][9], in some cases purposely neglecting it. Some studies on permeation of multi-component gases, on the other hand, have included the gas-phase equilibrium in their analyses [10,12].…”

“…The solubility of hydrogen and its isotopes in metals from mixtures of these gases has also been studied in the literature, applying empirical relationships to model equilibrium dissolution of hydrogen isotopes. In particular, Hickman assumes that mixtures of hydrogen and deuterium gases behave as a one-component gas with an effective solubility constant that follows a linear mixing rule [3]; this assumption has been propagated in the literature [4][5][6][7][8][9] without consideration of the fundamental thermodynamics of dissolution. In the following presentation, we use classical thermodynamics to describe equilibrium dissolution of hydrogen and deuterium in metals from the gas phase and compare these results to empirical relationships from the literature.…”

Modeling and Data Analysis of a Palladium Membrane Reactor for Tritiated Impurities Cleanup

“…Continuity equations for the retentate are: In the above model, H represents both hydrogen and tritium. The permeation model accounts for the different rates of the two hydrogen isotopes (Ackerman and Koskinas, 1972):…”

Hydrogen isotope separation by permeation through palladium membranes

“…Based on a simple model [3,1] that describes the permeation of hydrogen isotopes, the separation factor and the separation efficiencies have been calculated. The results reveal that numerical studies are highly useful to set appropriate working regimes for a permeator so that highest separation factors are achieved.…”