NOVELTY - Production of hydrogen and carbon dioxide from hydrocarbons (I) comprises: supplying a first gaseous stream (II) of (I), a molecular-oxygen and optionally, steam to a first reaction zone (III); catalytically partially oxidizing (I) in (II); supplying a second gaseous stream of (I), steam and first effluent to second reaction zone (IV); catalytically reforming (I); separating hydrogen from the reformed gas; and removing a gaseous stream.    USE - The invention deals with the process for the production of hydrogen and carbon dioxide from hydrocarbons, where the hydrogen may be used in a fuel cell.    ADVANTAGE - The process provides substantially pure hydrogen, where the heat for the endothermic steam reforming reaction is efficiently provided to that reaction, and the carbon dioxide produced by the process is in a concentrated form.    DETAILED DESCRIPTION - Production of hydrogen and carbon dioxide from hydrocarbons (I) comprises: supplying a first gaseous stream (II) of (I), a molecular-oxygen (containing gas) and optionally steam to a first reaction zone (III) (comprising a fluidized bed of partial oxidation catalyst); catalytically partially oxidizing (I) in (II) in (III) at 700-1400degreesC, to form a first effluent (comprising carbon oxides, steam and hydrogen); supplying a second gaseous stream of (I), steam and the first effluent to a second reaction zone (IV) (comprising a fluidized bed of steam reforming catalyst); catalytically reforming (I) fed to (IV) at 200-700degreesC, to produce a reformed gas (comprising hydrogen and carbon dioxide); separating hydrogen from the reformed gas by a hydrogen-permeable selective membrane, which is located in (IV); and removing a gaseous stream rich in carbon dioxide from (IV) as the second effluent.    INDEPENDENT CLAIMS are included for:    (1) a reactor for the production of hydrogen and carbon dioxide from (I) comprising: (III) and (IV) in series, (in which (III) is located below (IV), where (III) is a reaction zone for the partial oxidation of (I) in a fluidized catalyst bed, (IV) is a reaction zone for steam reforming of (I) in a fluidized catalyst bed, and a hydrogen-permeable selective membrane is located in (IV), the hydrogen- permeable selective membrane having a retentate side facing the catalyst bed and a permeate side); inlets for introduction of a first gaseous stream of (I), a molecular-oxygen containing gas, and optionally steam into (III); inlets for the introduction of a second stream of (I) and steam between (III) and (IV); an outlet for hydrogen that is in fluid communication with the permeate side of the hydrogen-permeable selective membrane; and an outlet for discharging a gaseous stream; and    (2) a fuel cell system comprising in series a reactor.    DESCRIPTION OF DRAWING(S) - The figure shows a reactor for the production of hydrogen and carbon dioxide.    Reactor (1)    First reaction zone (2)    Second reaction zone (3)    Inlet (4)    Gaseous hydrocarbon stream (5)    Steam (6)    Air supply conduit (9)    Distibution screens (12,19)    Membrane unit (20)    Hydrogen outlet (24)    Carbon dioxide outlet (25)