, Volume 11, Supplement 1, pp 427–432 | Cite as

Knudsen Diffusion and Viscous Flow Dusty-Gas Coefficients for Pelletised Zeolites from Kinetic Uptake Experiments

  • Richard S. Todd
  • Paul A. Webley
  • Roger D. Whitley
  • Matthew J. Labuda


A simple volumetric uptake apparatus was used to determine uptake data of N2 on a sample of LiLSX zeolite for two different particle sizes, two temperatures, and a variety of different dosing pressure levels. Using a mass and energy conservation model for the dosing and sample volumes and the Dusty Gas Model + viscous flow for the mass transfer description at the pellet level, the Knudsen and viscous flow structural parameters were derived. Our analysis gave structural coefficients C K = 0.0827 ± 0.018 and C v = 0.0608 ± 0.026 which gave good agreement across all of the experimental runs conducted for both particle sizes and all pressure ranges. From these, tortuosity coefficients for Knudsen and viscous flow were derived and gave τ K = ε P,macro/C K = 3.7 ± 0.8 and τ v = ε P,macro/C v = 5.1 ± 2.2 respectively. These are in good agreement with reported values. The apparatus and procedure is not very sensitive to the viscous flow coefficient but is sensitive to the Knudsen coefficient. All other parameters of the model were measured or determined by calibration experiments. This study suggests that the apparatus may be useful for determination of some of the fundamental structural coefficients employed in the Dusty Gas Model.


kinetics gas diffusion uptake mass transfer 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Brandani, S., “Analysis of the Piezometric Method for the Study of Diffusion in Microporous Solids:Isothermal Case” Adsorption, 4, 17–24 (1998)CrossRefGoogle Scholar
  2. Breck, D.W., Zeolite Molecular Sieves, John Wiley and Sons, New York, 1974.Google Scholar
  3. Burganos, V.N. and S.V. Sotirchos “Knudsen Diffusion in Parallel, Multidimensional or Randomly Oriented Capillary Structures” Chem. Eng. Sci., 44, 2451–2462 (1989).CrossRefGoogle Scholar
  4. Chun, C. and C.-H. Lee, “Comparison of Adsorption Dynamics of a Ternary Hydrogen Mixture in Equilibrium and Kinetic Separation Beds” in Proc. 2nd. Pacific Basin Conf. Adsorption Sci. and Tech., pp. 371–375, Brisbane, Queensland, Australia, 14–18 May,(2000).Google Scholar
  5. Gladden, L.F., “Review Article Number 46. Nuclear Magnetic Resonance in Chemical Engineering:Principles and Applications, Chem. Eng. Sci., 49, 3339–3408 (1994).CrossRefGoogle Scholar
  6. Hartmann, R. and A., Mersmann, “Simulation of Single Pellet Adsorption Kinetics with Experimentally Determined Dusty Gas and Surface Diffusion Coefficients” Fundamentals of Adsorption 5, M.D. LeVan (Ed.), Kluwer Academic Publishers, Bostom Massachusetts, pp. 361–368,1996.Google Scholar
  7. Haugaard, J. and H., Livbjerg, “Models of Pore Diffusion in Porous Catalysts” Chem. Eng. Sci., 53, 2941–2948 (1998).CrossRefGoogle Scholar
  8. Kärger J, “Measurement of Diffusion in Zeolites—A Never Ending Challenge?” Adsorption, 9, 29–35 (2003).CrossRefGoogle Scholar
  9. Qinglin, H., S.M., Sundaram and S. Farooq, “Revisiting Transport of Gases in the Micropores of Carbon Molecular Sieves” Langmuir, 19, 393–405 (2003).CrossRefGoogle Scholar
  10. Reyes, S. and K.F. Jensen, “Estimation of Effective Transport Coefficients in Porous Solids Based on Percolation Concepts” Chem. Eng. Sci., 40, 1723–1734 (1985).CrossRefGoogle Scholar
  11. Ruthven, D.M. and Z., Xu, “Diffusion of Oxygen and Nitrogen in 5A Zeolite Crystals and Commercial 5A Pellets” Chem. Eng. Sci., 48, 3307–3312 (1993).Google Scholar
  12. Satterfield, C.N. and T.K. Sherwood, The Role of Diffusion in Catalysis, Addison-Wesley Publishing, Massachusetts, 1963.Google Scholar
  13. Sircar, S. and R., Kumar, “Non-Isothermal Surface Barrier Model for Gas Sorption Kinetics on Porous Adsorbents” J. Chem. Soc., Faraday Trans. 1, 80, 2489–2507 (1984).Google Scholar
  14. Todd, R.S. “A Theoretical and Experimental Study of a Rapid Pressure Swing Adsorption System for Air Separation” Ph.D. Dissertation, Monash University, Australia, 2003.Google Scholar
  15. Todd R.S., G. Buzzi Ferraris, D. Manca, and P.A. Webley, “Improved ODE Integrator and Mass Transfer Approach for Simulating a Cyclic Adsorption Process” Comput. and Chem. Eng., 27, 883–899 (2003).CrossRefGoogle Scholar
  16. Todd, R.S. and P.A. Webley, “Macropore Diffusion Dusty-Gas Coefficient for Pelletised Zeolites from Breakthrough Experiments in the O2/N2 System” Submitted (2004).Google Scholar
  17. Wloch, J., “Effect of Surface Etching of ZSM-5 Zeolite Crystals on the Rate of n-hexane Sorption” Microporous and Mesoporous Materials, 62, 81–86 (2003).CrossRefGoogle Scholar

Copyright information

© Springer Science + Business Media, Inc. 2005

Authors and Affiliations

  • Richard S. Todd
    • 1
  • Paul A. Webley
    • 1
  • Roger D. Whitley
    • 2
  • Matthew J. Labuda
    • 2
  1. 1.Department of Chemical EngineeringMonash UniversityClaytonAustralia
  2. 2.Air Products and Chemicals Inc.AllentownUSA

Personalised recommendations