Integration of Reforming and Membrane-Based Purification

The reforming process (as applied to a hydrocarbon or alcohol) yields a product stream that consists predominantly of hydrogen, carbon monoxide, carbon dioxide, water, unconverted feedstock, and trace by-products. This product stream mixture, called reformate, is unsuitable for direct use in low-temperature PEMFC and AFC, and some trace by-products (notably organosulfur compounds) will poison both high-temperature fuel cells and low-temperature fuel cells. A membrane for separating and purifying hydrogen from reformate must also be chemically compatible with the compounds in the reformate stream. 

Integrating a membrane with a reformer may be done in one of two ways the membrane may be close to the reformer, but downstream from the reaction zone, or the membrane may be located within the reaction zone. The latter is referred to as a membrane reactor and this approach offers the advantage of being able to shift chemical equilibrium by removing product hydrogen simultaneously with chemical reaction. The difficulties of membrane reactors include the following  

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