Chromatographic study of alkanes in silicalite: Equilibrium properties

Hufton, Jeffrey R.; Danner, Ronald P.

doi:10.1002/aic.690390605

Cited by 76 publications

(80 citation statements)

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“…Adsorption data employed in this study were obtained from Bakker et al [14] for hydrogen, and Millot et al [41] for isobutane. Comparable results have been obtained for isobutane adsorption in silicalite-1 [42][43][44]. Table 1 gives the membrane geometric parameters and Table 2 the adsorption data in MFI material [14,41] for hydrogen and isobutane, respectively.…”

Section: Composite Membrane Parameterssupporting

confidence: 52%

Experimental study and numerical simulation of hydrogen/isobutane permeation and separation using MFI-zeolite membrane reactor

et al. 2000

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A composite alumina-MFI-zeolite membrane has been prepared by a pore-plugging method. Transport through this membrane is controlled by molecular size and adsorption properties, as expected for a defect-free zeolite composite layer.Single gas transport was studied for hydrogen and isobutane. In the studied temperature range, (323-723 K) for isobutane and (277-723 K) for hydrogen, transports were activated. Isobutane exhibited a flux maximum at 450 K, whereas hydrogen flux declined with temperature.These different permeation behaviors were modeled using Maxwell-Stefan equations taking into account only surface diffusion. Activation energies were obtained from the model by fitting the experimental data. They were calculated to be 31 kJ mol −1 for isobutane and 1.9 kJ mol −1 for hydrogen. The diffusion coefficients calculated at 323 K differed by four orders of magnitude.Separation experiments with a mixture of hydrogen and isobutane in a 293-723 K temperature range were performed. Typical permeation behavior was observed for a mixture of weakly and strongly adsorbed molecules. At room temperature, hydrogen permeation was hindered by stronger adsorbed isobutane molecules in the micropores. H 2 /i-C 4 H 10 separation experiments showed a separation factor of 25 at 723 K, a typical temperature of the isobutane dehydrogenation in membrane reactors. RésuméUne membrane composite alumine-zéolithe MFI est préparée par une méthode de bouchage de pores. Le transport à travers la membrane est contrôlé par la taille des molécules et leurs propriétés d'adsorption, comme on peut s'y attendre dans une couche composite zéolithique sans défaut.Le transport des gas purs est étudié pour l'hydrogène et l'isobutane. Dans les domaines de température étudiés, 323-723 K pour l'isobutane et 277-723 K pour l'hydogène, le transport de ces deux gaz est activé. Le flux d'isobutane présente un maximum à 450 K, alors que celui d'hydrogène diminue avec la température.Ces différents comportements en perméation sont modélisés en utilisant les équations de Maxwell-Stefan appliquées uniquement à la diffusion de surface. L'ajustement de l'équation du modèle aux données expérimentales permet d'obtenir les energies d'activation de diffusion. Celles-ci sont de 31 kJ mol −1 pour l'isobutane et de 1.9 kJ mol −1 pour l'hydrogène. Les coefficients de diffusion calculés à 323 K sont dans un rapport de 10 4 .Des expériences de séparation hydrogène/isobutane sont effectuées dans une gamme de température de 293 à 723 K. Il a été observé un comportement en perméation typique d'un mélange binaire de molécules gazeuses fortement et faiblement * Corresponding author. Fax: +33-4-7244-5399. E-mail address: dalmon@catalyse.univ-lyon.fr (J.-A. Dalmon).0920-5861/00/$ -see front matter ©2000 Elsevier Science B.V. All rights reserved. PII: S 0 9 2 0 -5 8 6 1 ( 9 9 ) 0 0 2 8 3 -7 254 P. Ciavarella et al. / Catalysis Today 56 (2000) [253][254][255][256][257][258][259][260][261][262][263][264] adsorbées. À température ambiante, la perméation d'hydrogène est gênée pa...

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Section: Composite Membrane Parameterssupporting

confidence: 52%

Experimental study and numerical simulation of hydrogen/isobutane permeation and separation using MFI-zeolite membrane reactor

et al. 2000

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“…The first moment or retention time of the peak ( t R ) is also calculated by integration (Hufton and Danner, 1993). A sim-pier expression for estimating the second moment is given by Conder and Young (1979, p. 82…”

Section: Moments Methodsmentioning

confidence: 99%

Chromatographic study of alkanes in silicalite: Transport properties

Hufton

Danner

1993

AIChE Journal

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“…However, one has to bear in mind, that for protolytic cracking and dehydrogenation the experimentally measured values are the apparent activation energies. Therefore, they should be increased for the heat of isobutane adsorption of about 12-14 kcal/mol [32,33]. In addition, the smallest H(OH)AI(OH) 3 cluster used in our calculations has the lower acidity than the real zeolite.…”

Section: Discussionmentioning

confidence: 99%