Modelling and simulation of permeation behaviour on Pd/PSS composite membranes prepared by “pore-plating” method

The performance of selective hydrogen permeation of different Pd-containing (Pd thickness in the range 11–30 μm) structured membranes has been studied in this work. Pd was deposited over tubular porous stainless steel supports by the novel electroless pore-plating method. The permeation properties of the membranes have been tested at different operating conditions: retentate pressure (1–4 bar), temperature (623–723k) and hydrogen molar fraction of feed gas (0.7–1). A complete selectivity to hydrogen was observed for all tested conditions, ensuring 100% purity in the hydrogen permeate flux. Permeances in the range of 2.3–6.4×10−4 mol/m2 s Pa0.5 were obtained, maintaining a good mechanical stability of the composite system. A mathematical model considering the different mass transfer resistances in series of the composite membrane, e.g. Pd active layer, porous support and gas phase film layer, has been proposed to describe the permeation of hydrogen. The model also considers the axial variations of hydrogen concentration that takes place in tubular membranes. A set of experimental data has been used to fit the empirical parameters of the model, using another set of experiments for validating the proposed model.