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Adsorption

, Volume 2, Issue 4, pp 299–309 | Cite as

Role of convection and diffusion in a single pore with adsorptive walls

  • Syed M. Taqvi
  • M. Douglas Levan
Article

Abstract

The importance of intraparticle convection during and after the pressurization step of a pressure swing adsorption process is assessed by considering a single, cylindrical, closed-end pore with adsorptive walls exposed to a binary mixture of an adsorbable component and an inert gas. Gas-phase mass transfer is comprised of pore diffusion and convection, and surface diffusion occurs in the adsorbed phase. Concentration, velocity, and flux profiles are obtained inside the pore both during and after pressurization. Solutions are obtained analytically for the limiting cases of no adsorption, no diffusion, and no inert gas. Complete solutions of the material balance equations are obtained by orthogonal collocation. The pressurization rate, the adsorptive capacity of the pore wall, and the gas-phase mole fraction are varied over a wide range to study the relative importance of convection and diffusion under different conditions. Results show that convection makes a large contribution to transport in the pore except when the adsorbable component has a small mole fraction.

Keywords

intraparticle convection intraparticle diffusion pressure swing adsorption 

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References

  1. Aris, R., “Interpretation of Sorption and Diffusion Data in Porous Solids,”Ind. Chem. Engng Fundam.,22, 150–151 (1983).Google Scholar
  2. Buzanowski, W.A., R.T. Yang, and O.W. Hass, “Direct Observation of the Effects of Bed Pressure Drop on Adsorption and Desorption Dynamics,”Chem. Engng. Sci.,44, 2392–2394 (1989).Google Scholar
  3. Hindmarsh, A.C., “LSODE and LSODI, Two New Initial-Value Ordinary Differential Equation Solvers,”ACM-SIGNUM Newsletter,15(4), 10–11 (1980).Google Scholar
  4. Knaebel, K.S. and F.B. Hill, “Pressure Swing Adsorption: Development of an Equilibrium Theory for Gas Separations,”Chem. Engng. Sci.,40, 2351–2360 (1984).Google Scholar
  5. Lu, Z., J.M. Loureiro, M.D. LeVan, and A.E. Rodrigues, “Intraparticle Convection Effect on Pressurization and Blowdown of Adsorbers,”AIChE J.,38, 857–867 (1992a).Google Scholar
  6. Lu, Z., J.M. Loureiro, M.D. LeVan, and A.E. Rodrigues, “Effect of Intraparticle Forced Convection on Gas Desorption from Fixed Beds Containing “Large-Pore” Adsorbents,”Ind. Engng. Chem. Res.,31, 1530–1540 (1992b).Google Scholar
  7. Rodrigues, A.E., J.M. Loureiro, and M.D. LeVan, “Simulated Pressurization of Adsorption Beds,”Gas Sep. and Purif.,5, 115–124 (1991).Google Scholar
  8. Ruthven, D.M. and K.F. Loughlin, “The Diffusional Resistance of Molecular Sieve Pellets,”Can. J. Chem. Engng.,50, 550–552 (1972).Google Scholar
  9. Ruthven, D.M. and J. Kärger,Diffusion in Zeolites and Other Microporous Solids, Chaps. 1 and 11. Wiley Interscience, New York, (1992).Google Scholar
  10. Sundaram, N. and P.C. Wankat, “Pressure Drop Effects in the Pressurization and Blowdown Steps of Pressure Swing Adsorption,”Chem. Engng. Sci.,43, 123–129 (1988).Google Scholar

Copyright information

© Kluwer Academic Publishers 1996

Authors and Affiliations

  • Syed M. Taqvi
    • 1
  • M. Douglas Levan
    • 1
  1. 1.Department of Chemical EngineeringUniversity of VirginiaUSA

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