Steam Reforming Natural Gas in a Membrane Reactor with a Nickel Catalyst at High Temperatures

The steam conversion of various hydrocarbon mixtures, including natural and associated petroleum gases (APGs), has been modeled in a membrane module (MM) with an industrial nickel catalyst and palladium alloy foil in order to obtain pure hydrogen. The working part of the module consists of two cylindrical chambers separated by a membrane partition. The upper chamber is evacuated, while the lower chamber is maintained at atmospheric pressure. With a uniform feed of raw materials along the outer perimeter of the lower chamber, the problem is reduced to finding the flows of water vapor, carbon oxides, hydrogen, and methane and its homologues from the solution of a system of nonlinear ordinary differential equations of the first order. A wide temperature range of 600 K is considered < T < 1000 K at permissible values of the ratio of water vapor to hydrocarbon mixture flows at the inlet. At a fixed temperature, feedstock flows at the input are found at which the hydrogen yield and hydrocarbon conversion reaches 100%, while the maximum hydrogen flow through the membrane is achieved at the minimum permissible ratios of input flows of water vapor and hydrocarbons for a given mixture. A comparison of calculations with experimental data is carried out for a number of hydrocarbon mixtures at different temperatures and determining parameters.