Process for operating a water vapor reforming system, a reforming system operable thereby and a fuel cell system operating process

A process for operating a system for water vapor reforming a hydrocarbon or hydrocarbon derivative, comprising an evaporator, a reforming reactor adapted to be used in a partial oxidation operation or for water vapor reforming, a hydrogen separating stage having a selectively hydrogen-permeable membrane, and a catalytic burner device in thermal contact with heat-conducting partitions with the evaporator and the reforming reactor, said process including a warmed normal operating condition and a cold start of the system, wherein

• when the system is in a warmed normal operating condition, the hydrocarbon or the hydrocarbon derivative is subjected to a water vapor reforming reaction in the reforming reactor to form a reformate gas containing hydrogen which is separated from the remaining reformate gas constituents in the hydrogen separating stage at a normal operating pressure and normal operating temperature;
• further wherein
• during the cold start of the system, a heating operation is carried out wherein during a first operating phase the reforming reactor is used in the partial oxidation operation at a heating operating pressure which is lower than the normal operating pressure to partially oxidize the hydrocarbon or the hydrocarbon derivative thereby forming a product gas, the product gas is fed through the hydrogen separating stage into the catalytic burner device and is catalytically burned therein with an oxygen-containing gas, and wherein during a subsequent second operating phase, the reforming reactor is used for the water vapor reforming operation and pressure therein is increased from the heating operating pressure to the normal operating pressure.