In this work, the combined role of mass and heat dispersion effects on the performance of adiabatic large-scale membrane reactor modules is investigated. The model developed can be used in predicting membrane reactor performance under industrial process conditions. The membrane reactor configuration adopted in this study assumes that the water gas shift reaction (WGS) takes place in the feed side of the membrane reactor that is filled with catalytic particles. The membrane reactor is equipped with a highly selective ceramic membrane. To undertake a systematic analysis of the role of mass and heat dispersion on the performance of the WGS membrane reactor, various versions of a two-dimensional model have been applied. It is shown that none of the mass and heat dispersion effects can be neglected a priori and their impact on the membrane reactor operation depends on the process characteristics.