Hydrogen generation by methane steam reforming in a thermally coupled membrane reformer-combustor has been experimentally studied. The concentric three-compartment reactor indirectly couples methane steam reforming with catalytic methane combustion and with a Pd-Ag membrane, to provide extrapure hydrogen. The reactor call be independently operated at steady state with the enthalpy required for the steam reforming and for heat losses provided by methane oxidation. The study focuses oil the experimental demonstration of two approaches for the optimization of hydrogen generation in terms of power Output and process efficiency: increasing the membrane separation ability and recycling reformer products to the combustion section.