Parameters for SMRs

The primary function of a steam reformer is to produce hydrogen. Hydrocarbon feed gas is mixed with steam and passed through catalyst-filled tubes. Hydrogen and carbon oxides are produced by the following reactions. 

The first reaction is the reforming reaction, and the second is the shift reaction. Both reactions produce hydrogen. Both reactions are limited by thermodynamic equilibrium. The net reaction is endothermic. These reactions take place under carefiilly controlled external firing, with heat transfer from the combustion gas in the firebox to the process gas within the catalyst-filled tubes. 

The carbon monoxide in the above product gas is subsequently shifted almost completely to hydrogen in a downstream catalytic reactor by further utilization of reaction (eqn. 2). 

Typical hydrocarbon feedstocks for the reformer include natural gas, refinery gas, propane, LPG, and butane. Naphtha feedstocks with final boiling points up to about 430°F can also be processed. 

Typical fuels for the reformer are light hydrocarbons such as natural gas and refinery gas, although distillate fuels are sometimes used. Residual fiiels are not utilized since the contained metals can damage the reformer tubes. 

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