Steam reforming refers to the endothermic, catalytic conversion of light hydrocarbons (Methane to Gasoline) with water vapour. A simplified basic flow diagram of the conventional steam reforming process is shown in Figure B.1. Industrial scale processes of this kind are normally carried out at temperatures of 850°C and pressures in the order of 25 bar, according to:
Exothermic catalytic conversion (shift reaction) of the resulting carbon monoxide produces pure hydrogen according to:
Figure B.1 A simplified basic flow diagram of the conventional steam reforming 
The energy released from this reaction can however not be directly used for the reformation. Using absorption or membrane separation, the carbon dioxide is removed from the gas mixture, which is further cleaned to remove other unwanted components. The leftover gas consisting of approx. 60% combustible parts (H2, CH4, CO) is, along with a portion of the primary gas itself, used to fuel the reformer. Steam reforming is not apt to convert hydrocarbons heavier than naphtha to hydrogen, thus partial oxidation of heavier feedstock is used to produce hydrogen. Heavy residues from petrochemical processes are the preferred feedstock for the production of hydrogen and carbon monoxide-rich gases.
Was this article helpful?