Nonuniform catalyst distribution for inorganic membrane reactors: Theoretical considerations and preparation techniques

Yeung, King Lun; Aravind, R.; Zawada, Robert J.X.; Szegner, J.; Cao, Giacomo; Varma, Arvind

doi:10.1016/s0009-2509(05)80062-4

Cited by 55 publications

(3 citation statements)

References 17 publications

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“…Reaction and separation can thus be performed in one step. Either the catalyst can be deposited into the membrane pores or the membrane can be packed , with a catalyst. A third alternative is to deposit the catalyst only on the inner or outer membrane surface next to, or as part of, the separation layer.…”

Section: Introductionmentioning

confidence: 99%

Comparing and Modeling the Dehydrogenation of Ethanol in a Plug-Flow Reactor and a Pd−Ag Membrane Reactor

Keuler

Lorenzen

2002

Ind. Eng. Chem. Res.

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In this study the performance of a membrane reactor was compared to that of a plug-flow reactor for the dehydrogenation of ethanol. The membrane consisted of a 2.2 µm Pd-Ag film (23 wt % Ag) deposited on the inside of an asymmetric R-alumina membrane tube (SCT). The membrane tube was packed with a 14.5 wt % Cu on SiO 2 catalyst. The effects of the sweep gas flow rate, the ethanol feed flow rate, and the temperature on acetaldehyde yield and selectivity were investigated. A model was developed using measured kinetic data and membrane permeance data to predict the performance of the membrane reactor. The membrane reactor performed significantly better than the plug-flow reactor at all temperatures tested. The best results were obtained at 275 °C, where the total ethanol exit conversion increased from 45% (plug-flow reactor) to 60% at low feed flow rates and from 36% to 46% at high feed flow rates. The acetaldehyde selectivity for the membrane reactor increased from the lower 80% range to above 90% at 275 °C. The model underpredicted the total ethanol conversion, indicating that the measured reaction rate parameters for a differential reactor were lower than those for the membrane reactor.

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Section: Introductionmentioning

confidence: 99%

Comparing and Modeling the Dehydrogenation of Ethanol in a Plug-Flow Reactor and a Pd−Ag Membrane Reactor

Keuler

Lorenzen

2002

Ind. Eng. Chem. Res.

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“…As in the work of Harold and Lee, the heterogeneity of the system (i.e., the presence of the inactive layer) was key to the results obtained. Finally, precise control of the thicknesses of the active (Pt/γ-Al 2 O 3 ) and inert layers can be obtained by successive slip-casting steps, as demonstrated by Yeung et al…”

Section: Introductionmentioning

confidence: 99%

Coupling of Consecutive Reactions in a Two-Layer, Flow-Through Catalytic Membrane

Alfonso

Menéndez

Santamarı́a

2001

Ind. Eng. Chem. Res.

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A flow-through catalytic membrane has been used to carry out consecutively the oxidative and non-oxidative dehydrogenation of butane, with the aim of achieving thermal and chemical coupling of both processes. To this end, two distinct zones were created across the membrane radius: the first, containing V supported on MgO, was prepared by sequential impregnation, and the second, containing Pt-Sn on γ-Al 2 O 3 , was prepared by by sol-gel procedures. The investigation highlights some of the problems encountered during membrane preparation, which are discussed and related to the reaction results observed. When the preparation procedures are tailored to achieve segregation of the catalytic materials in both layers, and when the operating conditions are such that complete oxygen consumption within the oxidative dehydrogenation layer is obtained, the use of the flow-through, two-layer membrane allows stable operation and, at the same time, gives rise to increased conversion and selectivity.

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“…The concept of nonuniform catalyst distribution within the pellets of a PBMR, well-mixed on both the feed and permeate sides, has also been demonstrated recently. It has been shown theoretically that for many cases of practical interest, optimal PBMR performance can be achieved by distributing the catalyst as a step function within the pellets (Yeung et al, 1994). Experimentally, Cannon and Hacskaylo (1992) studied cyclohexane dehydrogenation in inert and active porous Vycor glass tubes packed with Pd/AI,O, catalyst granules.…”

mentioning

confidence: 99%

Effect of catalyst distribution in a membrane reactor: Experiments and model

1997

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Nonuniform catalyst distribution for inorganic membrane reactors: Theoretical considerations and preparation techniques

Cited by 55 publications

References 17 publications

Comparing and Modeling the Dehydrogenation of Ethanol in a Plug-Flow Reactor and a Pd−Ag Membrane Reactor

Comparing and Modeling the Dehydrogenation of Ethanol in a Plug-Flow Reactor and a Pd−Ag Membrane Reactor

Coupling of Consecutive Reactions in a Two-Layer, Flow-Through Catalytic Membrane

Effect of catalyst distribution in a membrane reactor: Experiments and model

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