A simulation study of a membrane reactor for the water-gas shift reaction is presented. A pseudohomogenous 1D mathematical model is considered to describe the performance of the membrane reactor under steady-state operation. The membrane consists on a dense Pd layer (selective to H-2) deposited on a porous ceramic support. The influence of operating pressure and thermal effects on the membrane reactor performance is analyzed and the results are compared with those corresponding to a reactor with no hydrogen permeation. (C) 2009 Elsevier B.V. All rights reserved.