Measurement of zeolitic diffusivities and equilibrium isotherms by chromatography
β Scribed by Dhananjai B. Shah; Douglas M. Ruthven
- Publisher
- American Institute of Chemical Engineers
- Year
- 1977
- Tongue
- English
- Weight
- 643 KB
- Volume
- 23
- Category
- Article
- ISSN
- 0001-1541
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β¦ Synopsis
Abstract
The chromatographic method has been used to study the sorption and diffusion of methane, ethane, propane, and cyclopropane in 5A molecular sieve. Both the equilibrium isotherms and the time constants for zeolitic diffusion, obtained from the chromatographic peaks, agree well with the values obtained previously by the gravimetric method, thus confirming the validity of the experimental technique. The results obtained in several previously reported chromatographic studies are reviewed, and it is shown that the apparent discrepancies between chromatographic and gravimetric data arise mainly from differences in the way in which the micropore diffusivity is defined. The relative advantages and disadvantages of the gravimetric and chromatographic methods are briefly considered.
π SIMILAR VOLUMES
A mathematical model is developed which describes the pulse response of a chromatographic column packed with crystal zxolite powder, thus allowing the crystal diffusivity to be determined independently of the pellet diffusivity which is present in more conventional beds. This continuum model allows
Experimental results are reported for the adsorption of propane and n-butane in a column packed with Linde 5A ZeoIite crystals, and methane, propane, a-and ire-butane in a column packed with silicalite crystals. The adsorption equilibrium constant K and crystal diffusivity 0, were obtained at differ
Intracrystalline diffusivities of Y type zeolite were measured in the temperature range of 323-573 K for four aromatics: benzene, toluene, and ortho-, alld para-xylene, and four paraffins: n-hexane, n-heptane, n-oclane and iso-octane. Three model equations tbr calculating the intracrystalinc dillhsi