Modelling for a Palladium Membrane Water-Gas Shift Reactor

This work is focused on the integration of palladium membranes, permeable to hydrogen, in tubular catalytic reactors for the Water-Gas Shift (WGS) reaction CO + H2O → CO2 + H2, in view of pre-combustion carbon capture. The membrane allows hydrogen separation from the reaction products, so that the reaction conversion is increased, leading simultaneously to an increased H2 recovery and to an effective H2 and CO2 separation.A control-oriented dynamic model of the integrated process has been set up (by Dymola and Matlab-Simulink), including mass and energy conservation in the reactor feedgas stream and in its catalytic porous medium and a description of the WGS reaction kinetics, and accounting for the permeation characteristics of the membrane itself and of its support, for the possible presence of nitrogen as a sweep gas and for possible membrane poisoning by CO. Model parameters have been identified thanks to experimental data from a lab-scale test rig.