Inorganic membrane reactors dense metallic membranes

Some dense inorganic membranes made of metals and metal oxides are oxygen specific. Notable ones include silver, zirconia stabilized by yttria or calcia, lead oxide, perovskite-type oxides and some mixed oxides such as yttria stabilized titania-zirconia. Their usage as a membrane reactor is profiled in Table 8.4 for a number of reactions decomposition of carbon dioxide to form carbon monoxide and oxygen, oxidation of ammonia to nitrogen and nitrous oxide, oxidation of methane to syngas and oxidative coupling of methane to form C2 hydrocarbons, and oxidation of other hydrocarbons such as ethylene, methanol, ethanol, propylene and butene. 

Inorganic membrane reactors for hydrogen production an overview with particular emphasis on dense metallic... 

Thermal shock resistance. Temperature swing as part of the normal cycles of operation or regeneration of the membranes or membrane reactors can lead to deleterious thermal shock. The materials for the various components in a membrane reactor should be carefully selected to impart good thermal sh k resistance. This is particularly important for high temperature reactions. Also listed in Table 9.5 is a summary of various membrane materials along with qualitative description of their resistance to thermal shock. Again, the available data apply to dense materials. While various metal oxides have been made into commercial inorganic membranes, they tend to be affected by thermal shock much more than other ceramic materials. 

Membranes are classified by whether the thin permselective layer is porous or dense, and by the type of material (organic, polymeric, inorganic, metal, etc.) this membrane film is made from. The choice of a porous vs. a dense film, and of the type of material used for manufacturing depends on the desired separation process, operating temperature and driving force used for the separation the choice of material depends on the desired permeance and selectivity, and on thermal and mechanical stability requirements. For membrane reactor applications, where the reaction is coupled with the separation process, the thin film has also to be stable under the reaction conditions. 

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