The gas-to-liquid process, consisting of the partial oxidation of methane (POM) followed by the Fischer-Tropsch reaction, IS promising alternative to conventional oil processing for the production of liquid fuels. The cost of a conventional POM process is mainly determined by cryogenic air separation and could be greatly reduced by using oxygen permselective perovskite membranes instead. These membranes operate at temperatures similar to POM processes and can thus be integrated into a catalytic membrane reactor. To investigate the implications of this integration an adiabatic thermodynamic analysis has been carried out for both oxygen- and air-based POM processes, focusing on the influence of the feed temperature and composition on the syngas yield and quality. ThIS nalysis revealed that much higher feed temperatures are required for air-based POM processes to reach similarly high syngas yields. Because the Fischer Tropsch reaction is carried out at much lower temperatures, recuperative heat exchange becomes essential for air-based POM processes. This is preferably carried out inside the reactor using the reverse flow concept, since external heat transfer at elevated temperatures is expensive. To combine the POM reaction, air separation and recuperative heat exchange into a single apparatus a reverse-flow catalytic membrane reactor (RFCMR) is proposed.