CATALYTIC COMBUSTION OF PROPANE IN A MEMBRANE REACTOR WITH SEPARATE FEED OF REACTANT .1. OPERATION IN ABSENCE OF TRANS-MEMBRANE PRESSURE-GRADIENTS

A pilot plant study on propane catalytic combustion in a membrane reactor with separate reactant feeds is presented. The membrane consisted of a porous alumina tube activated by insertion into its pores of a Pt/gamma-Al2O3 catalyst. The role of reactants concentration and of the feed flow rates were studied in the transport-controlled operating regime, where a number of interesting properties of this reactor setup can be exploited (absence of reactant slip through the membrane, lower risks of thermal runaways, possibility of increasing conversion by application of a pressure difference over the membrane, etc.). Attention is here focused on operation in the absence of trans-membrane pressure gradients. The reactor fluid-dynamics are investigated, too. The experimental results are in good agreement with the predictions of an isothermal model, analytically solved and based on the simplifying assumption that the reaction takes place in a limited zone inside the membrane (i.e. a surface for infinitely fast reactions).