Membrane reactors, methane partial

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).

The viability of one particular use of a membrane reactor for partial oxidation reactions has been studied through mathematical modeling. The partial oxidation of methane has been used as a model selective oxidation reaction, where the intermediate product is much more reactive than the reactant. Kinetic data for V205/Si02 catalysts for methane partial oxidation are available in the literature and have been used in the modeling. Values have been selected for the other key parameters which appear in the dimensionless form of the reactor design equations based upon the physical properties of commercially available membrane materials. This parametric study has identified which parameters are most important, and what the values of these parameters must be to realize a performance enhancement over a plug-flow reactor. 

S. Pei, M.S. Kleefisch, T.P. Kobylinski, K. Faber, C.A. Udovich, V. Zhang-McCoy, B. Dabrowski, U. Balachandran, R.L. Mieville and R.B. Poeppel, Failure mechanisms of ceramic membrane reactors in partial oxidation of methane to synthesis gas. Catal. Lett., 30 (1995) 210-212. 

Jin, W., Gu, X., Li, S. et al. (2000) Experimental and simulation study on a catalyst packed tubular dense membrane reactor for partial oxidation of methane to syngas. Chemical Engineering and Science, 55 (14), 2617-2625. 

Ikeguchi M,MimiuaT, Sekine Y, Kikuchi E and Matsukata M (2005), Reaction and oxygen permeation studies in Smo,4Bao.6Coo,2Feo,803.5 membrane reactor for partial oxidation of methane to syngas, Appl CatalA-Gen, 290,212-220. 

Jin W, Li S, Huang P, Xu N, Shi J and Lin Y S (2000), Tubular lanthanum cobaltite perovskite-type membrane reactors for partial oxidation of methane to syngas , / Membrane Sci, 166,13-22. 

Zhang Y, Liu J, Ding W and Lu X (2011), Performance of an oxygen-permeable membrane reactor for partial oxidation of methane in coke oven gas to syngas , fwe/, 90,324-330. 

Figure 14.16 Scheme of the electrochemical membrane reactor for partial oxidation of methane [119]. 

Basile, A. and Paturzo, L. (2001). An Experimental Study of Multilayered Composite Palladium Membrane Reactors for Partial Oxidation of Methane to Syngas, Catal Today, 67, pp. 55-64. 

Tsai, C., Dixon, A., Moser, W., et al. (1997). Dense Perovskite Membrane Reactors for Partial Oxidation of Methane to Syngas, AICHE J., 43, pp. 2741-2750. 

Jin, W, Li, S., Huang, R, etal. (2000). TnbnlarLanthanumCobaltite Perovskite-Type Membrane Reactors for Partial Oxidation of Methane to Syngas, J. Membrane Set, 166, pp. 13-22. Sammells, A., Schwartz, M., Mackay, R., etal. (2000). Catalytic Membrane Reactors for Spontaneous Synthesis Gas Production, Catal. Today, 56, pp. 325-328. 

Ikeguchi, M., Mimura, T., Sekine, Y., etal. (2005). Reaction and Oxygen Permeation Studies in Smo.4Ba o.6P 0.8Coo.203 5 Membrane Reactor for Partial Oxidation of Methane to Syngas, Appl. Catal. A Gen., 290, pp. 212-220. 

Yin, X., Hong, L. and Liu, Z. (2007). Asymmetric Tubular Oxygen-Permeable Ceramic Membrane Reactor for Partial Oxidation of Methane, J. Phys. Chem. C, 111, pp. 9194-9202. 

Zhang, Y, Liu, J., Ding, W., et al. (2011). Performance of an Oxygen-Permeable Membrane Reactor for Partial Oxidation of Methane in Coke Oven Gas to Syngas, Fuel, 90, pp. 324-330. 

Yang, C., Xu, N.R and Shi, J. (1998) Experimental and modeling study on a packed-bed membrane reactor for partial oxidation of methane to formaldehyde. Industrial Engineering Chemistry Research, 37, 2601-2610. 

Fig. 5. Methane conversion and oxygen flux during partial oxidation of methane in a ceramic membrane reactor. Reaction conditions pressure, 1 atm temperature, 1173 K, feed gas molar ratio, CH Ar = 80/20 feed flow rate, 20 mL min-1 (NTP) catalyst mass, 1.5 g membrane surface area, 8.4 cm2 (57).

One example of membrane reactors is oxidation, in which oxygen from one phase diffuses from one side of an oxygen-permeable membrane to react with a fuel on the other side of the membrane. This avoids a high concentration of O2 on the fuel side, which would be flammable. A catalyst on the fuel side of the membrane oxidizes the fuel to partial oxidation products. One important process using a membrane reactor is the reaction to oxidize methane to form syngas,... 

The present study investigates a different approach. The membrane is used to allow the desired intermediate product to escape from the reaction zone before it is consumed by further reaction. This use of a membrane reactor was first suggested by Michaels [15]. The partial oxidation of methane, which is a challenging reaction of the type propos for this application of membrane reactors, has been analyzed herein. There is no thermodynamic limitation for the production of carbon dioxide and water, actually these products are favored. It is desired to remove any partial oxidation product, for example formaldehyde, before it has a chance to be further oxidized. 

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