Premium
Dynamics of flow and diffusion of adsorbing gases in Al 2 O 3 and Pd‐Al 2 O 3 pellets
Author(s) -
Dogan Meltem,
Dogu Gülsen
Publication year - 2003
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690491218
Subject(s) - tortuosity , knudsen diffusion , knudsen flow , pellets , knudsen number , diffusion , hydrogen , chemistry , materials science , helium , thermodynamics , flow (mathematics) , inert , inert gas , surface diffusion , porosity , analytical chemistry (journal) , adsorption , mechanics , chromatography , composite material , organic chemistry , physics
A nonisobaric pulse‐response technique was proposed for the simultaneous analysis of flow and diffusion of adsorbing tracers in porous solids. Relative contributions of viscous flow, Knudsen flow, surface flow, and effective diffusion of adsorbing (hydrogen and carbon dioxide) and inert (helium) tracers in alumina and Pd‐alumina pellets were evaluated. Hydrogen permeability was shown to increase by Pd impregnation into alumina, due to the contribution of surface flow, especially at low temperatures. The tortuosity factor, corresponding to the viscous and Knudsen flow, was found to be less than the tortuosity factors evaluated from effective diffusivities obtained from isobaric pulse‐response experiments.