Thin PdCu membrane for hydrogen purification from in-situ produced methane reforming complex mixtures containing H2S

A 0.9 µm PdCu (69 wt% Pd) membrane prepared by an electroless plating method on a ceramic tubular support was tested in hydrogen sulfide containing streams. H2S/H2 mixtures with 40 and 100 ppmv of H2S were tested in order to observe the reversibility of sulfur addition. The membrane permselectivity operating in H2S/complex mixtures with around 32 ppmv of H2S in CH4, CO, CO2 and H2 was also tested. The streams were in-situ produced by Methane Steam Reforming and Methane Catalytic Partial Oxidation reactions. Prior to the tests with H2S, the hydrogen flux of the membrane at 773 K and 2 bar of pressure difference was 0.92 mol m−2 s−1. Membrane hydrogen flux decreased by around 50-80% in the tests with H2S/H2 mixture, but it recovered to the original values after removing H2S. In H2S/complex mixtures operation, the flux decrease was smaller due to concentration polarization phenomena. Although no sulfide compounds where detected on the membrane by SEM−EDX, XRD or XPS, the H2S or the employed temperatures seem to induce Cu segregation to the membrane surface.