Hydrogen separation membranes applications

Although the mixed conduction is detrimental to fuel cell application, the high electronic conductivity of doped ceria in low p02 conditions can be exploited in hydrogen separation membrane technology. The chemical, thermal expansion and processing compatibilities of the two oxides in the composite make pervoskite-ceria combination suitable for the mixed conducting membrane application. 

Fig. 9.1 Application of hydrogen separation membrane for hydrogen production and CO2 sequestration...

General criteria for selection of materials for the processing of hydrogen separation membranes are discussed. Performance and stability standards required for applications in high temperature membrane reactors have been focused. The correlations between pore structure and stability issues of membranes made of amorphous materials, specifically silica membranes are discussed in detail. 

E. Gardeniers, H. V. Jansen, F. C. Gie-lens, M. C. Elwenspoek, Preparation of palladium-silver alloy films by a dual-sputtering technique and its application in hydrogen separation membrane,... 

Fontaine M-L, Norby T, Earring Y, Grande T, Bredesen R. Oxygen and hydrogen separation membranes based on dense ceramic conductors. In R. Mallada and M. Menendez (eds.). Inorganic Membranes Synthesis, Characterization and Applications. Membrane Science and Technology Series, Vol. 13. Elsevier B.V., Amsterdam, The Netherlands, 2008. 

A. L. Mejdell, T. A. Peters, M. Stange, H. J. Venvik and R. Bredesen, Performance and application of thin Pd-alloy hydrogen separation membranes in different configurations, J. Taiwan Inst. Chem. Eng., 2009, 40, 253-259. 

Although the development of new metals as alternatives to Pd in hydrogen separation membranes is very promising, many aspects concerning the stability and reliability of these innovative membranes have yet to be defined. The main problems to be solved are embrittlement under hydrogenation cycles and permeance/selectivity performances appropriate to the hydrogen separation processes of practical interest. Therefore, only a few application studies are reported here. 

Although the results of the research on these new materials for hydrogen separation membranes are very promising, no important applications are reported at the present time. The aspects of stability and reliability still have to be addressed. Examples of applications are reported for the refractory metals which exhibit a good resistance to aggressive environments such as hydroiodic acid. A study has also demonstrated that Nb or Ta dense membranes could be applied for hydrogen recovery from the decomposition of HI in the iodine-sulphur process for thermochemical hydrogen production. 

Igi,R.,Yoshioka,T.,Ikuhara,Y. H.,Iwamoto,Y. andTsuru,T. (2008) Characterization of co-doped silica for improved hydrothermal stability and application to hydrogen separation membranes at high temperatures./ournal of the American Ceramic Society, 91,2975-2981. 

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