Mechanical stability, requirement for

A1203 catalysts originates from interactions other than those existing in the binary system Cu/ZnO. The structural promotion by alumina is a very significant factor in the formulation of industrial catalysts, however, as it imparts chemical and mechanical stability required for a long-lived catalyst in large-scale reactors. 

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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