Oxygen exchange, porous support

The porous layer is required to ensure the thermo-mechanical integrity of the thin dense layer. This support has (i) to allow gas species diffusion, (ii) to present good chemical and thermal compatibility with the dense layer, (iii) to have mixed-conducting properties in order to shift oxygen exchanges at gas/solid interfaces inside its whole thickness, and (iv) to be of low cost for industrial applications. 

A preferred embodiment of an oxygen transport membrane would thus have a thin porous support on the feed side to improve oxygen exchange, a thin dense separation membrane, a fine pore structure interfacial layer to facilitate oxygen transfer out of the membrane and a coarse porous support to maximize product flow and provide the structural support. An example is shown in Fig. 6.4. The coarse porous support material could be made out of inert material because it is not chemically active in the transport of oxygen. This allows the use of less expensive materials which may also have better strength characteristics. 

---