High temperature membrane technology reactor

The membrane tubes must be sealed, possibly to each other and to the collector plate of the reactor vessel. The sealing has to be adherent and mechanically strong but also gas-tight and thermally resistant, up to temperatures of at least 700°C. These high demands make sealing one of the most important problems in current high temperature membrane technology. 

Ilias and Govind(lO) have reviewed the development of high temperature membranes lor membrane reactor application. Hsieh(4) has summarized the technology in the area of important inorganic membranes, the thermal and mechanical stabilities of these membranes, selective permeabilities, catalyst impregnation, membrane/reaction considerations, reactor configuration, and reaction coupling. 

Membrane Reactor. Another area of current activity uses membranes in ethane dehydrogenation to shift the ethane to ethylene equiUbrium. The use of membranes is not new, and has been used in many separation processes. However, these membranes, which are mostly biomembranes, are not suitable for dehydrogenation reactions that require high temperatures. Technology has improved to produce ceramic and other inorganic (90) membranes that can be used at high temperatures (600°C and above). In addition, the suitable catalysts can be coated without blocking the pores of the membrane. Therefore, catalyst-coated membranes can be used for reaction and separation. 

Alexeeva O.K., Alexeev S.Yu., Amirkhanov D.M., Kotenko A.A., Chelyak M.M., Shapir B.L. High-temperature catalytic membrane reactors for processes including hydrogen. Membranes. Ser. Critical technologies (in Russian) 2003 JN°3 (19) 20-31. 

While the aforementioned and other novel membrane reactors hold great promises, many material, catalysis and engineering issues need to be fully addressed before the inorganic membrane reactor technology can be implemented in an industrial scale. This is particularly true for many bulk-processing applications at high temperatures and often harsh chemical environments. Those issues will be treated in the subsequent chapters. 

Finally, the current status of the inorganic membrane technology is summarized for an overall perspective. The future is speculated based on that perspective to provide a framework for future developments in the synthesis, fabrication and assembly of inorganic membranes and their uses for traditional liquid-phase separation, high-temperature gas separation and membrane reactor applications. 

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