Pd-based membranes were studied for pure hydrogen separation from syngas: in particular, a mathematical model of a Pd membrane for hydrogen separation was developed.  This model could be used in process and assessment studies of the parameters which characterize the mass transfer phenomena (such as: hydrogen permeability, surface coverage and limiting step). By coupling the permeation and water gas shift reaction kinetics, it could also be used to evaluate the performances of the membrane reactor. Further, it could be helpful to evaluate the best assembly and sizing of a H2/CO2 separation system. The model takes into account the kinetics of H2 adsorption/desorption on Pd surface, the H2 permeation into the palladium bulk and in the porous layer, and the kinetics of CO, CO2, H2O, O2, H2S competitive adsorption/desorption on Pd surface. It was also comprehensive of flux equations and bulk mass, momentum and energy balance. The results released by the model were compared to the experimental data during both the transient phase and the steady state conditions. A satisfactory agreement between model and experimental data was found.

Validation of a Dynamic Model of Hydrogen Permeation through Pd-Based Membranes. A.Rossi, G.Lamonaca, A.Santucci, S.Tosti: International Journal of Greenhouse Gas Control, 2011, 5[3], 521-30