Methanol steam reforming over PdZn/ZnAl2O4/Al2O3 in a catalytic membrane reactor: An experimental and modelling study

A catalytic membrane reactor equipped with Pd–Ag metallic membranes and loaded with PdZn/ZnAl₂O₄/Al₂O₃ catalytic pellets was tested for the methanol steam reforming reaction (S/C = 1) aimed at producing a pure hydrogen stream for PEM fuel cell feeding. The catalyst was prepared in two steps. First, commercial γ-Al₂O₃ pellets were impregnated with ZnCl₂ and calcined at 700 °C to obtain a ZnAl₂O₄ shell, and subsequently impregnated with PdCl₂ and reduced at 600 °C to obtain PdZn alloy nanoparticles. The catalyst was tested both in a conventional packed bed reactor and in a catalytic membrane reactor. A 3D CFD non-isothermal model with mass transfer limitations was developed and validated with experimental data. The reactions of methanol steam reforming, reverse water-gas shift and methanation were modeled under different pressure, temperature and feed load values. The model was used to study and simulate the CMR under different operation conditions.