An equilibrium theory for catalytic steam reforming in membrane reactors

The study of integrated membrane reactors for the production of pure hydrogen is attracting increasing interest. In this work, we show how these systems may be described through pure transport models, accounting for the competition between different transport mechanisms, in the limit for either infinitely fast or infinitely slow reaction. The actual performance of a reactor will lie between these two limiting-case conditions. The results of this work highlight that the behavior of these systems may be described as a continuous sequence of equilibrium states. The main novelty of the study is in the introduction of a simple model that allows to evaluate integral quantities, such as hydrogen permeate flow rate and yield, on the basis of physical parameters and not through fitting of transport coefficients. Methane steam reforming has been chosen as a case study, but the conclusions reached may be extended to other integrated reactors for which the permeation law of the product across the membrane is non-linear.