NOVELTY - Fuel cell-heating unit operable with fuel, preferably fuel gas, comprises a fuel cell (1) for generating electricity and heat, a device for reactive desulfurization of the fuel with a selective oxidation- and/or hydrolysis catalytic converter, and an exhaust-gas discharge for discharging the exhaust gas from the fuel cell and/or an afterburner (4) downstream of the fuel cell. The dosage device is connected to the exhaust gas discharge, such that at least a part of the exhaust gas of the fuel cell-heating unit is used as the oxygen-containing gas.    USE - Used as a fuel cell-heating unit.    ADVANTAGE - The fuel cell-heating unit exhibits an improved efficiency and emission properties.    DETAILED DESCRIPTION - Fuel cell-heating unit operable with fuel, preferably fuel gas, comprises a fuel cell (1) for generating electricity and heat, a device for reactive desulfurization of the fuel with a selective oxidation- and/or hydrolysis catalytic converter for converting the sulfur compound by adding oxygen-containing gas supplied at a dosage device and at least one adsorbent for adsorptive removal of sulfur oxides from the combustion gas, in the direction of flow of the fuel, and an exhaust-gas discharge for discharging the exhaust gas from the fuel cell and/or an afterburner (4) downstream of the fuel cell. The dosage device is connected to the exhaust gas discharge, such that at least a part of the exhaust gas of the fuel cell-heating unit is used as the oxygen-containing gas An INDEPENDENT CAIM is also included for reactive desulfurization of a combustion gas in the fuel cell-heating unit, comprising supplying the oxygen-containing exhaust gas from the fuel cell process to desulfurized fuel gas, and supplying the mixture to a selectively acting oxidation catalyst, where the mixture of fuel and admixed gas has an oxygen content of 2-4%.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic representation of the Fuel cell-heating unit.    Fuel cell (1)    Cathode air supply module (2)    Reformer (3)    Afterburner (4)    Gas valve (5)