On the high pressure performance of thin supported Pd–23%Ag membranes—Evidence of ultrahigh hydrogen flux after air treatment

摘要: Abstract The hydrogen flux, selectivity and stability of ∼1.9–3.8 μm thick supported palladium alloy (Pd–23%Ag) films are reported. Applying a feed pressure 26 bar, one the highest fluxes reported equal to 2477 mL min−1 cm−2 (STP) or 132 kg H2 m−2 h−1 was measured at 400 °C. This flux corresponds permeance 1.5 × 10−2 mol m−2 s−1 Pa−0.5. H2/N2 permselectivity 25 bar transmembrane difference 2900. Allowing value n float between 0.5 1, in order obtain best fit ( p H 2 r e t − m ) , gives for 0.631 after air pre-treatment correction support resistance. analysis data suggests that diffusional transport through membrane is rate-limiting. By forcing 0.5, permeability values as function have been obtained linking it qualitatively solution diffusion behaviour. At limiting zero partial pressure, permeabilities 9.1 × 10−9 mol m−1 s−1 Pa−0.5 3.2 × 10−8 mol m−1 s−1 Pa−0.5 before treatment, respectively. During continuous operation over 85 days, showed good up 350 °C while nitrogen leakage increases very slowly higher temperatures (Pfeed = 10 bar).