Ceramics reactors for

A study of a ceramic reactor for on-site hydrogen production from propane at temperatures between 800 and 1000 °C was reported by Mitchell and Kenis [46]. They showed that the ceramic microreactor can be used with an S C ratio as low as 1.095 without coking or deactivation of the mthenium catalyst deposited on the SiC porous monoUths. 

Le Clerq, M. (1996). Ceramic reactor for use with corrosive supercritical fluids, AIChE J., 42, pp. 1798-1799. 

Shao, Z., Xiong, G., Dong, H., et al. (2001). Synthesis, Oxygen Permeation Study andMembrane Performance of a Bag 5 Sro,5 Coq.s Feo.2 O3—5 Oxygen-Permeable Dense Ceramic Reactor for Partial Oxidation of Methane to Syngas, Sep. Purif. Technol., 25, pp. 97-116. 

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. 

Types ofSCT Catalysts. The catalysts used in the SCR were initially formed into spherical shapes that were placed either in fixed-bed reactors for clean gas apphcations or moving-bed reactors where dust was present. The moving-bed reactors added complexity to the design and in some appHcations resulted in unacceptable catalyst abrasion. As of 1993 most SCR catalysts are either supported on a ceramic or metallic honeycomb or are direcdy extmded as a honeycomb (1). A typical honeycomb block has face dimensions of 150 by 150 mm and can be as long as one meter. The number of cells per block varies from 20 by 20 up to 45 by 45 (39). 

GP 7] [R 8] In a later study, a yield of about 40% is found for the same steel reactor [55]. For a ceramic reactor, an even higher yield of 45% is reported. This is explained by a reduction in blank activity (Figure 3.40) (see the sections Activity of... 

Schematics of an oxygen membrane reactor for catalytic POx of methane. A blown up section on the left-hand side shows the details of the ceramic membrane wall explaining the mechanism of oxygen permeation across the membrane. /- is the chemical potential of oxygen and ai and

Fig. 4. Configuration of a ceramic membrane reactor for partial oxidation of methane. The membrane tube, with an outside diameter of about 6.5 mm and a length of up to about 30 cm and a wall thickness of 0.25-1.20 mm, was prepared from an electronic/ionic conductor powder (Sr-Fe-Co-O) by a plastic extrusion technique. The quartz reactor supports the ceramic membrane tube through hot Pyrex seals. A Rh-containing reforming catalyst was located adjacent to the tube (57).

Fig. 6. Configuration of a ceramic membrane reactor for partial oxidation of methane. The membrane disk was prepared by pressing Bao.5Sro.5Coo.8Feo.2O3-s oxide powder in a stainless steel module (17 mm inside diameter) under a pressure of (1.3-1.9) X 109 Pa. The effective area of the membrane disk exposed to the feed gas (CH4) was 1.0 cm2 (72).

Plasma reactors, for CVD, 5 807-808 Plasma sintering, ceramics processing, 5 663... 

The use of a monolithic stirred reactor for carrying out enzyme-catalyzed reactions is presented. Enzyme-loaded monoliths were employed as stirrer blades. The ceramic monoliths were functionalized with conventional carrier materials carbon, chitosan, and polyethylenimine (PEI). The different nature of the carriers with respect to porosity and surface chemistry allows tuning of the support for different enzymes and for use under specific conditions. The model reactions performed in this study demonstrate the benefits of tuning the carrier material to both enzyme and reaction conditions. This is a must to successfully intensify biocatalytic processes. The results show that the monolithic stirrer reactor can be effectively employed in both mass transfer limited and kinetically limited regimes. 

Figure 17.26. Reactor for hydrofining diesel oils, with ceramic lining (Sukhanov, Petroleum Processing, Mir, Moscow, 1982).

A 15-fold glass tube parallel-packed bed reactor has been described [28-30], which is close to conventional catalyst testing equipment. The same authors also reported a 64-fold ceramic block reactor and a ceramic monolithic reactor for the screening of up to 250 catalysts in parallel. The individual catalysts were coated... 

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). 

Catalytic Hydrocarbon Combustion 1 [CHCC 1] Ceramic Micro Reactor for Butane Combustion... 

Porous ceramic membranes for catalytic reactors - overview and new ideas. Journal of Membrane Science, 181, 3-20. 

E. Kikuchi, Palladium/Ceramic Membranes for Selective Hydrogen Permeation and Their Application to Membrane Reactor , Catal. Today, 25 333-37 (1995). 

Industrial reactors for catalytic incineration of VOCs contain ceramic or another inert packing material on the boundaries of the catalyst bed [9, 26]. In such reactors, the temperature after the inert ceramic packing can be estimated by the almost linear expression... 

IV. Development of porous ceramic membranes for a solar thermal water-splitting reactor, Int. J. Hydrogen Energy, 25 1043-1050 (2000). 

In addition to the equipment displayed, another probe was utilized for extended residence time studies. This probe consists of a mullite tube with a ceramic crucible affixed at the top. This probe was utilized to capture and hold particles in the reactor for 10 minutes so that pyrolysis could be completed. 

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