Measurement of zeolitic diffusivities and equilibrium isotherms by chromatography

Shah, Dhananjai B.; Ruthven, Douglas M.

doi:10.1002/aic.690230605

Cited by 96 publications

(56 citation statements)

References 15 publications

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“…These include, but are not limited to, Schneider and Smith (1968), Ma and Mancel(1972), Hashimoto and Smith (1973), Shah and Ruthven (1977), Chihara et al (1978), Ruthven and Kumar (1979), Hsu and Haynes (1981), Chiang et al (1984a,b), Boniface and Ruthven (1985), and Fu et al (1986). Further description of some of the key developments in CPC (and TPC) can be found in the thesis of Hufton (1992).…”

Section: Theorymentioning

confidence: 93%

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Chromatographic study of alkanes in silicalite: Transport properties

Hufton

Danner

1993

AIChE Journal

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Section: Theorymentioning

confidence: 93%

“…Thus, the macropore resistance term can be omitted from the second moment expression. The following expression for the second moment is based on work by Haynes and Sarma (1973) and Shah and Ruthven (1977):…”

Section: Moments Methodsmentioning

confidence: 99%

Chromatographic study of alkanes in silicalite: Transport properties

Hufton

Danner

1993

AIChE Journal

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“…For CzHe in 4A molecular sieve at 298 K reported diffusivities range from 4 X cmz/s (Kondis and Dranoff, 1971;Eagan and Anderson, 1975;Antonson and Dranoff, 1969). Those for CzH6 in 5A molecular sieve at 298 K range from 6 X cmz/s (Antonson and Dranoff, 1969;Derrah, 1973;Shah and Ruthven, 1977). Since 13X molecular sieve has larger pore windows than 5A molecular sieve, the micropore diffusivity of CzH6 in 13X molecular sieve should be larger than the value in 5 b molecular sieve, as found in the present study.…”

Section: Micropore Diffusiviiymentioning

confidence: 64%

“…Such a model is more realistic for describing sorption in pelletized particles and in some types of molecular sieves. Thus, most of the recent authors in the literature have accepted the bidispersed pore model in the chromatographic study of intraparticle diffusivities in molecular sieves (Shah and Ruthven, 1977;Chihara et al, 1978;Kumar, 1979 Andrieu andSmith, 1980;Hsu and Haynes, 1981).…”

Section: Introductionmentioning

confidence: 98%

Adsorption equilibrium constants and intraparticle diffusivities in molecular sieves by tracer‐pulse chromatography

Hyun

Danner

1985

AIChE Journal

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A perturbation chromatography technique using radiotracer gases has been developed to determine the adsorption equilibrium constants and diffusivities in molecular sieves. The ethane and ethylene 13X molecular sieve systems were studied in regions of high concentration. The data obtained by this technique are shown to be in agreement with equilibrium data obtained by static methods and with kinetic data obtained by adsorption uptake and chromatographic methods, but not with kinetic data obtained using NMR techniques. The tracer-pulse chromatographic technique is much more efficient for obtaining gas adsorption equilibria and intraparticle diffusivities and is considerably easier to adapt to wide pressure and temperature ranges than the conventional methods. S. H. HYUN and R. P. DANNER Department of Chemical EngineeringThe Pennsylvania State Unlversity University Park, PA 16802 SCOPEDespite the obvious industrial importance of adsorption equilibria and kinetics in porous materials such as molecular sieves, reliable information in this area is still quite limited. This condition is the result of experimental difficulties and, in part, of the lack of a complete model to describe the complex adsorption kinetic process in porous solids. The adsorption kinetic or intraparticle diffusivity data reported in the literature have frequently shown discrepancies of several orders of magnitude among different investigators using different techniques of measurement.Ruthven (1983) recently reviewed methods for determining diffusivities in zeolites. Most earlier studies used direct measurement of the adsorption uptake on an exposed layer of adsorbent. A chromatographic method is also being used which is based on the analysis of response of an adsorption bed to a concentration pulse or step change at the inlet. More recently NMR methods have been used to measure adsorption diffusivities. The chromatographic techniques are easier to operate, more efficient in producing data, and more suitable for higher temperature and pressure ranges. Conventional chromatographic methods, however, have been limited to infinitely dilute adsorbed phase concentrations with only one adsorbable component. Furthermore, Karger and Ruthven (1981) have raised doubts about the micropore diffusivities determined by adsorption uptake and chromatographic techniques. Use of NMR for the study of adsorption diffusivities involves an extension of the methods originally developed to study self-diffusion in liquids. Application of NMR is restricted to molecules which contain a sufficiently high density of atoms with impaired nuclear spins, such as found with the hydrogens in hydrocarbons.The objective of this work was to develop a tracer-pulse chromatographic technique (i,e., perturbation chromatography technique) which can be used for both pure and multicomponent systems over the entire concentration range. A mathematical model using bidispersed pore structure, which is more realistic in pelletized particles, has been developed to describe the chromatographic behav...

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“…They used a variety of experimental techniques to measure adsorption isotherms such as gravimetric, chromatographic and headspace chromatography. Through a series of papers (Shah and Ruthven 1977;Haq and Ruthven 1986;Ruthven and Kumar 1979;Boniface and Ruthven 1985), Prof. Ruthven also popularized the use of chromatographic technique for measuring adsorption isotherms. In the use of chromatographic method, he used different perturbations such as pulse input (Shah and Ruthven 1977), step change (Ruthven and Kumar 1979) and sinusoidal input .…”

Section: Adsorption Isotherm Modeling Measurement and Data Analysismentioning

confidence: 99%

Doug Ruthven and Jörg Kärger: Their individual and collective contributions to the field of zeolite science and engineering

Shah

2010

Adsorption

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Prof. Doug Ruthven and Prof. Jörg Kärger are two giants in the field of zeolite science and engineering. Over their academic careers encompassing almost forty years each, they have contributed significantly to the advancement of fundamental understanding of adsorption and diffusion in zeolites as well as their industrial applications. The author, in the beginning of his academic career, had an opportunity to spend two years as a post-doctoral fellow in Prof. Ruthven's laboratory at the University of New Brunswick (1975Brunswick ( -1977. This experience actually motivated me to spend my academic career in working in the field of zeolite adsorption and diffusion. Nearly thirty years later, I spent a year as a Gast Mercator Professor at the University of Leipzig in the laboratory of Prof. Kärger (2005. These two opportunities at two different ends of my academic career provided me with unique perspectives to reflect on the important contributions made by Professors Ruthven and Kärger to the field of zeolite science and technology. This article summarizes my personal perspectives on the breadth and depth of their contributions.

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Measurement of zeolitic diffusivities and equilibrium isotherms by chromatography

Cited by 96 publications

References 15 publications

Chromatographic study of alkanes in silicalite: Transport properties

Chromatographic study of alkanes in silicalite: Transport properties

Adsorption equilibrium constants and intraparticle diffusivities in molecular sieves by tracer‐pulse chromatography

Doug Ruthven and Jörg Kärger: Their individual and collective contributions to the field of zeolite science and engineering

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