NOVELTY - An electrically heated reactor (8) for gas phase reforming comprises an enclosure; a reaction chamber, with at least two electrodes (2a, 2b, 4a, 4b) and a conductive lining (7) electrically insulated from the metallic wall of the enclosure; sources (1a) of gas to be reformed and oxidant gas; an outlet (1b) for the reformed gases; and an electric power source (13) for powering the electrodes, generating an electronic flux in the conductive lining and heating the lining.    USE - The reactors are used for reforming a gas containing optionally substituted hydrocarbon(s) and/or optionally substituted organic compound(s) containing carbon, hydrogen and heteroatom(s), in presence of an oxidant gas (claimed). In particular the reactors are used for: (1) producing synthesis gas, especially for methane production; (2) utilizing biogas from buried rubbish to produced energy and/or chemical products; (3) producing hydrogen for use as fuel for road vehicles, e.g. cars or buses; (4) producing hydrogen for portable or stationary applications, e.g. for feeding fuel cells in homes or road vehicles; or (5) desulfurization of sulfur-containing gases.    ADVANTAGE - Direct ohmic heating via a conductive lining is a simple method of utilizing electricity as heat source for endothermic reactions. Direct or alternating current can be used, and transformers may be unnecessary. The conductive lining may simultaneously serve as catalyst, and the electronic flux may improve catalysis and/or create electric arcs beneficial to the process. The reactors are formed from inexpensive, readily available materials; may be compact and/or in modular form; and give high yields. Desulfurization of the starting gas is unnecessary in some cases.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a gas phase reforming process carried out in the reactors.    DESCRIPTION OF DRAWING(S) - The figure shows a reforming reactor having perforated hollow disk electrodes.    Hollow tube for supply of gas to be reformed and oxygen (1a)    Hollow tube outlet for reformed gas (1b)    Hollow tube parts of first and second metallic electrodes (2a, 2b)    Hollow disk parts of the electrodes (4a, 4b)    Openings for injection of reactants (3)    Electrical insulation (5a, 5b)    Porous, conductive metallic lining material having catalytic action (7)    Reactor (8)    Refractory material (9)    Thermal insulation material (10)    Insulating joints of dielectric material (11)    Electrical connection points for the electrodes (12a, 12b)    Electrical power source (AC or DC) (13)    Thermocouple for monitoring temperature (14)    Earthed exterior steel wall (16)