Ceramic membranes composite membrane

Dynamic ceramic and composite membranes on tubular support... 

M.-D. Jia, B. Chen, R.D. Noble, and J.L. Falconer, Ceramic-zeolite composite membranes and their application for separation of vapor/gas mixtures, 7. Membrane ScL 90 (1994). 

In contrast, if the membrane is an inorganic composition (e.g., a dense metal membrane or a nanoporous ceramic membrane), the membrane module may be operated at the elevated temperature of 450 °C. In this case, there is no need for optional HEX 2 as the fuel gas stream will exit the membrane module at 450 °C and pass to the burner without further cooling. In addition to a net increase in overall process energy efficiency, the elimination of HEX 2 also represents a reduction in capital cost for the system. 

Meng Dong Jia, K.V. Peinemann and R.D. Behling, Ceramic zeolite composite membrane preparation, characterisation and gas permeation. /. Membr. Sci., 82 (1993) 15-26. 

In the filtration of fermentation broths, lysed yeast [21,88-91] microfiltration is used to separate the yeast cells and/or cell fragments. For the Ceramesh ceramic/metal composite membrane of 0.2 pm pore size a flux of 60 1/m h is reported [21] for lysed yeast, at a temperature of about 55°C and a solids concentration of up to 16-17%. The same magnitude of flux and solids concentration are obtained with whole yeast suspensions. Using Kubota membranes in the range of 50 nm to 0.8 pm Narukami et al. [88] choose 0.8 pm for their work with fermentation broth. They report a stable flux of 20 1/m h using suction (0.8 bar) on the permeate side as driving force, whereas the flux decreases as a... 

Bae J.M., Honma I., Hirakawa S. Synthesis and properties of ceramics-polymer composite membranes as high temperature proton conducting electrol)des. J. Korean Phys. Soc. 1999 35 315-319... 

Dense Cermet (Ceramic Metal) Composite Membranes... 

BalachandrianU.,LeeT. H.,Chen L.,Song S. J. and Dorris S.E.,Dense Ceramic-Metal Composite Membranes for Hydrogen Separation, Proc. 9 Int. Conf. on Inorganic membranes, LiUehammer (Norway), June 25-29,2006. 

As an example the use of ceramic membranes for ethane dehydrogenation has been discussed (91). The constmction of a commercial reactor, however, is difficult, and a sweep gas is requited to shift the product composition away from equiUbrium values. The achievable conversion also depends on the permeabihty of the membrane. Figure 7 shows the equiUbrium conversion and the conversion that can be obtained from a membrane reactor by selectively removing 80% of the hydrogen produced. Another way to use membranes is only for separation and not for reaction. In this method, a conventional, multiple, fixed-bed catalytic reactor is used for the dehydrogenation. After each bed, the hydrogen is partially separated using membranes to shift the equihbrium. Since separation is independent of reaction, reaction temperature can be optimized for superior performance. Both concepts have been proven in bench-scale units, but are yet to be demonstrated in commercial reactors. 

The vast increase in the application of membranes has expanded our knowledge of fabrication of various types of membrane, such as organic and inorganic membranes. The inorganic membrane is frequently called a ceramic membrane. To fulfil the need of the market, ceramic membranes represent a distinct class of inorganic membrane. There are a few important parameters involved in ceramic membrane materials, in terms of porous structure, chemical composition and shape of the filter in use. In this research, zirconia-coated y-alumina membranes have been developed using the sol-gel technique. 

Controlled removal of the template is especially important when zeolite based membranes are involved consisting of a continuous MFI layer on a ceramic or sintered metal support (ref. 14). In these novel composite ceramic membranes the formation of cracks during template removal would be detrimental. The unique properties (ref. 14) of metal-supported MFl-layer membranes prove that indeed crack formation can be essentially prevented. 

Siriwardane, R.V., J.A. Poston, E.P Fisher, T.H. Lee, S.E. Dorris, and U. Balachandran, Characterization of ceramic-metal composite hydrogen separation membranes consisting of barium oxide, cerium oxide, yttrium oxide, and palladium, Appl. Surf. Sci., 217, 43-49, 2003. 

Therefore, a team, led by the University of Alaska-Fairbanks, was formed to study these practical issues (75), including the composition of the ceramic membrane, seals that would join the ceramic and metal materials, membrane performance, and development of a ceramic that would resist warping and fracturing at the high temperatures of the conversion process. 

Astroquartz, fiber reinforcement for ceramic- matrix composite, 5 558t Asymmetric allylboration, 13 669-671 Asymmetric cellulose acetate membranes, 21 633... 

Burggraaf, A. J., K. Keizer and B. A. van Hassel. 1989b. Ceramic nanostructure materials, membranes and composite layers. Solid State Ionics 32/33 (Part 2) 771-82. 

In this chapter membrane preparation techniques are organized by membrane structure isotropic membranes, anisotropic membranes, ceramic and metal membranes, and liquid membranes. Isotropic membranes have a uniform composition and structure throughout such membranes can be porous or dense. Anisotropic (or asymmetric) membranes, on the other hand, consist of a number of layers each with different structures and permeabilities. A typical anisotropic membrane has a relatively dense, thin surface layer supported on an open, much thicker micro-porous substrate. The surface layer performs the separation and is the principal barrier to flow through the membrane. The open support layer provides mechanical strength. Ceramic and metal membranes can be either isotropic or anisotropic. 

Recently, attempts have been made to reduce the cost of palladium metal membranes by preparing composite membranes. In these membranes a thin selective palladium layer is deposited onto a microporous ceramic, polymer or base metal layer [19-21], The palladium layer is applied by electrolysis coating, vacuum sputtering or chemical vapor deposition. This work is still at the bench scale. 

During the last few years, ceramic- and zeolite-based membranes have begun to be used for a few commercial separations. These membranes are all multilayer composite structures formed by coating a thin selective ceramic or zeolite layer onto a microporous ceramic support. Ceramic membranes are prepared by the sol-gel technique described in Chapter 3 zeolite membranes are prepared by direct crystallization, in which the thin zeolite layer is crystallized at high pressure and temperature directly onto the microporous support [24,25],... 

Y. Zhu, R.G. Minet and T.T. Tsotsis, A Continuous Pervaporation Membrane Reactor for the Study of Esterification Reactions Using a Composite Polymeric/Ceramic Membrane, Chem. Eng. Sci. 51, 4103 (1996). 

---