Optimization of Steam Reforming of Methane in a Hydrogen-Filtering Membrane Module with a Nickel Catalyst and a Palladium-Alloy Foil.

A model is proposed for steam reforming of methane in a catalytic reactor, the working section of which includes two cylindrical chambers separated by a palladium foil membrane of the Pd, Pd–23% Ag, Pd–6% Ru, Pd–10% Ru, Pd–6% In–0.5% Ru, and Pd–6% In compositions. The upper chamber is evacuated and the atmospheric pressure is maintained in the lower chamber. Upon uniform feed of raw materials to the lower chamber, the problems are reduced to determination of the CH₄, H₂O, CO₂, CO, and H₂ flows from the solution of a system of first-order nonlinear ordinary differential equations. The 100% conversion of methane is achieved only when the ratio of water steam and methane input flows is more than two. Calculations are performed in the temperature range 700 1000 K at the ratio of steam/methane input flows belonging to this range [2, 10]. The optimum values of input flows of raw materials, at which the yield of hydrogen and the conversion of methane reach 100%, are determined. At optimum flows and specified temperature, the maximum hydrogen flow through the membrane is observed at the minimum permissible ratios of steam and methane input flows. [ABSTRACT FROM AUTHOR]