A method of producing a synthesis gas from a hydrocarbon containing gaseous feed in which the hydrocarbon containing gaseous feed is reacted in an autothermal reactor having separated reaction stages in which partial oxidation and steam methane reforming reactions occur. Each of the reaction stages has alternating separation zones and catalytic reaction zones. Oxygen separated by oxygen ion transport in the separation zone supports the partial oxidation reactions occurring in the catalytic reaction zones. Reactants are separately metered to the reaction stages to control temperatures within the reaction stages so that use of expensive high temperature materials is confined to one or more final reaction stages. Reaction stages can incorporate perforated planar members with regions of oxygen ion transport membrane material in registry with such perforated regions form the separation zones and the catalytic reaction zones.
U.S. GOVERNMENTAL INTEREST
 This invention was made with United States Government support under Cooperative Agreement number DE-FC26-01NT41096 awarded by the U.S. Department of Energy, National Energy Technology Laboratory. The United States Government has certain rights in this invention.