A dynamic study on axial dispersion and adsorption in catalytic monoliths


Ozkan G. , Dogu G.

INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, vol.36, no.11, pp.4734-4739, 1997 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 36 Issue: 11
  • Publication Date: 1997
  • Doi Number: 10.1021/ie9701027
  • Title of Journal : INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
  • Page Numbers: pp.4734-4739

Abstract

A dynamic procedure was used for the measurement of the axial dispersion coefficient, as well as the adsorption equilibrium and rate constants of CO, O-2, CH4, and C3H6 tracers on a monolithic catalyst washcoated by Pt-Al(2)O3. Using a transient axial dispersion model, moment expressions were derived for the inert and adsorbing tracers. From the second central moment of inert tracer response peaks, an average value of the axial dispersion coefficient was determined as 2.65 x 10(-4) m(2)/s for a ceramic monolith containing cells with square cross section. The results indicated that axial dispersion in such a monolith is higher than the corresponding value in a circular tube. The adsorption equilibrium constants of the adsorbing tracers (CO, O-2, CH4, C3H6) and the heat of adsorptions were determined from the time delay of the response curves measured in the temperature range of 76-300 degrees C, while the adsorption rate parameters were evaluated from the second central moments, A detailed analysis of the results indicated that pore diffusion resistance in the Pt-Al2O3 layer is negligible and also that film mass-transfer resistance is much smaller than the adsorption resistance.