Hydrogen permeation in 2.5 micrometer Pd-Ag membranes,
an experimental and modeling study
Marco Giacinti Baschetti
Assistant Professor
Department of Chemical, Mining and Environmental Engineering (DICMA)
University of Bologna
Abstract
The permeation properties of a series of 2.5 micrometer thick Pd-Ag membranes were tested in view of
their use in the purification of hydrogen produced by methane steam reforming. In particular, hydrogen
flux was measured in pure hydrogen permeation tests as well as in experiments conducted with binary
and ternary mixtures containing also nitrogen, water vapor, carbon monoxide and methane. The
different tests were performed at temperatures ranging from 473 to 723 K and at a trans-membrane
pressure differences up to about 3 bar. The results of the study showed the high potential of the
considered membranes for industrial application, and allowed to point out the critical points that should
be considered in the design of the membrane purification module. The experiments in hydrogennitrogen mixtures, carried out at different temperatures, hydrogen concentrations and feed flow rates,
confirmed the existence of a non-negligible concentration polarization phenomena in the experimental
modules. Tests involving water vapor and carbon monoxide on the other hand allowed to study the
inhibition of hydrogen permeation due to competitive interaction of such gases with the membrane
surface.
The gas phase resistance and the inhibition phenomena were then modeled through consistent
theoretical approaches that allowed the description of the experimental data obtained in different
working conditions.
Short CV
Marco Giacinti Baschetti is currently assistant professor in Department of chemical, mining and
environmental engineering (DICMA) of the University of Bologna where he also obtained his Ph.D in
chemical engineering in 2001. His scientific work is focused on the study of the mass transport
properties of films and membranes in view of their possible applications in separation processes as well
as in the development of new barrier materials. Such activity includes both experimental and modeling
work. The experimental characterization of solubility, permeability and diffusivity of several gases and
vapors in polymeric and inorganic matrices, is indeed often coupled with the mathematical modeling of
the results based on the numerical approaches or on analytical and thermodynamic models for the
correlation and prediction of the diffusivity and solubility in rubbers, in glassy polymers and composite
materials. The results of his work were published in several papers appeared in different international
scientific journals and books. In 2002 he has been conferred the William Doolittle Award from the
American Chemical Society for his study on the modeling of gas solubility in polymeric blends.