Dense ceramic membranes tubular membrane

There are three main types of dense ceramic membranes disk/flat sheet, tubular, and hollow fibers. The disk/flat sheet membranes are applied mostly in research work because they can be fabricated easily in laboratories with a small amount of membrane material. Comparatively, the hollow fiber membranes can provide the largest membrane area per volume but low mechanical strength, while the tubular membranes possess a satisfactory specific membrane area, high mechanical strength, and are easy to assemble in membrane reactors. Dense ceramic MRs can be constructed and operated in either packed bed MR or catalytic MR configurations. 

Dense ceramic membranes can be fabricated in three configurations disc/ flat-sheet membrane, tubular membrane and hollow fibre membrane. Their preparation processes are described respectively in details as follows. 

Dense ceramic membranes allow oxygen or hydrogen permeation in a dissociated or ionized form other than the conventional molecular diffusion, and thus exhibit extremely high selectivity (up to 100%). They can be incorporated into membrane reactors for a variety of oxidation and dehydrogenation reactions where the membrane functions as either a product extractor or a reactant distributor. Three configurations, that is, disc/flat-sheet, tubular and hollow fibre membranes have been applied in membrane reactors. They exhibit respective advantages/disadvantages in terms of the ease and cost of fabrication, the effective membrane area/volume ratio, and... 

After this chapter. Part 11 is dedicated to zeolite, ceramic and carbon membranes and catalysts used in membrane reactors. In Chapter 6 (Algieri, Comite and Capannelli) the remarkable properties of zeolite membranes are illustrated. Moreover, the key role of zeolite membrane reactors to improve the yield and the selectivity of reactions is particularly emphasised. Furthermore, the possibility of using zeolite membranes as micro-reactors and sensors is also discussed. Chapter 7 (Tan and Li) deals with dense ceramic membrane reactors, which are made from composite oxides usually having perovskite or fluorite structures with appreciable mixed ionic (oxygen ion and/or proton) and electronic conductivity. This chapter mainly describes the principles of various configurations (disc/flat-sheet, tubular and hollow fibre membranes) of dense ceramic membrane reactors and the... 

Air separation membranes are typically dense ceramic (typically perovskite) membranes, which selectively permeate oxygen in ionic form. Over the past two decades. Air Products (ITMs) and Praxair (oxygen transport membranes [OTMs]) have worked towards the commercial scale-up of these membranes for applications in power generation, gasification, and gas to liquid conversion [94]. Air Products has focused on a planar configuration, whereas Praxair on tubular membranes. 

Synthesis of HjOj from Hj and O2 Porous asymmetric ceramic membrane with carbon coating Pd, Pd-Ag, Pd-Pt dispersed Pd and Pd/Ag dense layer Tubular single channel O2 saturated liquid phase on the catalytic side, H2 gas on the support side Abate et al. (2005, 2006, 2006b), Melada et al. (2005, 2006)... 

Finally, dense ceramic oxide membrane-based eCMRs (Badwal Ciacchi, 2001 Fouletier Ghetta, 2009 Hibino, Ushiki, Kuwahara, 1997), which are available in both planar and tubular designs, have been investigated for O2 separation and compression at HT. Of course, the conventional (non-electrochemical) HT oxygen separation membranes are mixed oxide/electronic ceramics (Badwal Ciacchi, 2001). 

Tubular membranes with one dead-end can be prepared by cold isostatic pressing (CIP) with green machining method (Akin and Lin, 2002). Tlie ceramic powder is first pressed into cylindrical rods. A carbide bit is used to drill the rods into dead-end geometry. The dead-end tubes are then sintered and annealed at elevated temperatures into dense membranes. 

Hollow fibre membranes have a micro-tubular configuration with outer diameter of less than 2 mm. The above extrusion-sintering method can also be used to fabricate hollow fibre membranes. But the method mostly used to fabricate dense ceramic hollow fibre membranes is the phase... 

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