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Article
Diffusion Measurements Through Embedded Zeolite Crystals
AIChE Journal
  • Matthew S. Sun
  • Orhan Talu, Cleveland State University
  • Dhananjai B Shah, Cleveland State University
Document Type
Article
Publication Date
11-1-1996
Abstract
For the first time, a macroscopic method was used to measure directly diffusivity of fast diffusing species such as methane in silicalite. A form of Wicke–Kallenbach technique was applied to measure intracrystalline diffusivity. The technique uses a single embedded zeolite crystal as a membrane and a mass-selective detector to determine the transient mass response and hence the diffusion flux passing through the membrane. A concentration-difference driving force is used rather than a pressure-difference driving force. The diffusivities calculated from both adsorption and desorption transients were in excellent agreement, thus providing a check for the self-consistency of the data. The diffusivities of carbon dioxide, methane, ethane, propane and butane in silicalite between 30 and 70°C have been compared with those from the literature. The diffusivities reported here are between those measured with microscopic methods and those measured with other macroscopic methods.
DOI
10.1002/aic.690421102
Citation Information
Sun, M. S., Talu, O. & Shah, D. B. (1996), Diffusion measurements through embedded zeolite crystals. AIChE J., 42, 11, 3001–3007. doi: 10.1002/aic.690421102