Hydrogen Production by Steam Reforming of Hydrocarbons
Steam reforming of natural gas at petroleum refining facilities is the predominant means of producing hydrogen in the chemical process industries (CPI). In the overall steam methane reforming (SMR) reaction, methane reacts with steam at high temperatures and moderate pressures in catalyst- filled tubes to generate synthesis gas, a mixture of hydrogen, carbon monoxide and some carbon dioxide. Additional hydrogen can be generated from the carbon monoxide byproduct following the reforming reaction. Excess steam above the theoretical requirements is maintained to prevent the reforming catalyst from coking. A pre-reformer breaks down heavier hydrocarbons into methane ahead of the reforming reactions. The additional post- reformer catalyst reduces the overall total space velocity of the combined reformer and post reformer, thus achieving additional reaction. This reduces the downstream shift-reaction requirements.