NOVELTY - In a reformer with a reforming zone (12) in which fuel and a mixture of oxidant and at least partially oxidized fuel (from a downstream oxidation zone) are supplied for catalytic conversion into reformate, the reforming zone is divided into separate first and second catalytic reaction zones (32, 48), with an intermediate non-catalytically active homogenization zone (44) for gases leaving the first reaction zone.    USE - For converting fuel and oxidant into reformate (claimed), especially for supplying a gas with high hydrogen content to a fuel cell for generation of electrical energy. The fuel cells are typically used for force-heat coupling and as auxiliary power sources in automobiles.    ADVANTAGE - The reforming efficiency is increased using a compact, inexpensive arrangement requiring no complicated mechanical devices or control electronics. In particular higher reforming efficiency in the second partial reforming stage is ensured by homogenizing the gases from the first stage; and/or the specific gas supply arrangement provides a technically simple, compact, inexpensive construction.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a variant of the reformer, in which the fuel and mixture are supplied to the reforming zone (12) via an upstream common supply device, where the supply device is in the form of an annular mixing chamber (14) with its outlet side coupled with the reforming zone, to be supplied with fuel or mixture via openings (28) in the inlet side and with mixture or fuel via openings (34) in the casing surface.    DESCRIPTION OF DRAWING(S) - The figures show a sectioned view of a reformer system along the central axis; an enlarged sectioned view of the mixing chamber central body in the system; and a plan view of the mixing chamber central body.    Reformer system (10)    Reformer (12)    Mixing chamber (14)    Combustion exhaust gas outlet (16)    First and second cylinder casings (18, 20)    Sealing plate of second cylinder casing (22)    Central body of mixing chamber (24)    Sealing plate of central body (26)    Hole in sealing plate of central body (28)    Conical part of central body (30)    First reaction zone of reformer (32)    Opening in first cylinder casing (34)    Lid (36)    Gas distribution chamber (38)    Indentation in sealing plate of central body (40)    Fuel inlet (42)    Homogenization zone (44)    Annular screen (46)    Second reaction zone (48)    Lambda probe holder (50)    Combustion gas (52)    Combustion exhaust gas (54)