Membranes for High-Temperature Applications

Aprotic solvents, such as DMA, DMF, NMP and dioxane, currently still form a problematic class of solvents, since they are excellent solvents for polymers, and thus require extremely high chemical stability from both top layers and support layers. Finally, membranes for high-temperature applications are not yet available, with current reported upper limits in the range of 40-80°C only. 

Middelkoop, V., Chen, H., Michielsen, B., et al. (2014) Development and characterisation of dense lanthanum-based perovskite oxygen-separation capillary membranes for high-temperature applications. Journal of Membrane Science, 468, 250-258. 

Qian W, Shang Y, Fang M et al (2012) Sulfonated polybenzimidazole/zirconium phosphate composite membranes for high temperature applications. Int J Hydrogen Energy 37 12919-12924... 

The excellent separation properties of silica membranes prepared at temperatures as high as 825°C enables their use for high temperature applications, such as the dehydrogenation of H2S (chapter 8). Unfortunately no hydrothermal stability of the prepared layers could be tested because the mesoporous intermediate layer was not hydrothermally stable, but an indication of the hydrothermal stability of the unsupported material could be obtained from the specific surface area and XRD measurements. These measurements did not show any structural change in the material during SASRA treatment, which is a very hopeful result for the operation of real, supported, membranes at high temperatures and high pressures. 

In SOFCs, the difference in chemical potential or activity of oxygen across the electrolyte surfaces provides the electromotive force, and thus the electrical potential. Extensive research over the past decades has resulted in the development of cost-effective processes for the fabrication of thin and dense electrolyte layers. YSZ has been considered one of the best choices for high-temperature applications (>650°C) because of its feasibility of fabrication of a thin membrane, reasonable ionic conductivity, large ionic domain, and, most importantly, chemical and mechanical stability... 

Van Vccn H.M., R.A. Tcipstra, JP.B.M. Tol and H J. Vcringa, 1989, Three-layer ceramic alumina membranes for high temperature gas separation applications, in Proc. Int Conf. Inorg. Membr., Montpellier, France. 

Many different kinds of fuel cells are presently known, most of them suitable for high-temperature applications— for details see Ref. [101]. The polymeric proton-conducting membranes (polymer electrolyte membranes PEM) are however suitable for low temperamre operations (<100°C) and have the advantage of low weight. 

Most applications of GP use dense membranes of cellulose acetates and polysulfones. For high-temperature applications where polymers cannot be used, membranes of glass, carbon, and inorganic oxides are available, but they are limited in their selectivity. Almost all large-scale applications of GP use spiral-wound or hollow-fiber modules, because of their high packing density. 

As mentioned earlier, new developments in gas separation, catalysis, and petroleum industries have stimulated interest in microporous inorganic membranes suitable for high-temperature applications and with the property of high... 

In spite of the drawbacks of ceramic membranes for DH processes, namely their low separation selectivity to hydrogen, coke deposition, and their mechanical strength which is often insufficient for high temperature applications, a significant amount of experimental work has been reported on the subject of DH in ceramic membrane reactors [21, 27-29, 32, 40, 41] and there are some recent reports on ceramic membranes with high selectivity to H2 (e.g., [26]). 

Wang, Z., Ni, H., Zhao, C., Li, X., Fue, T. and Na, H. 2006. Investigation of sulfonated poly (ether ether ketone sulfone)/heteropolyacid composite membranes for high temperature fuel cell applications. 44- 1967-1978. 

Li M, Scott K (2010) A polymer electrolyte membrane for high temperature fuel cells to lit vehicle applications. Electrochim Acta 55 2123-2128... 

Design and Development of Highly Sulfonated Polymers as Proton Exchange Membranes for High Temperature Fuel Cell Applications... 

Truffier-Boutry, D., De Geyer, A., Guetaz, L., Diat, O., and Gebel, G. (2007) Structural study of zirconium phosphate-Nafion hybrid membranes for high-temperature proton exchange membrane fuel cell applications. Macromolecules, 40, 8259-8264. 

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