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The geometrical evaluation of effective diffusion coefficient in the liquid phase for porous bodies consisting of spherical elementary particles
Author(s) -
Kobayashi JunIchi,
Katsuzawa Hideo
Publication year - 1986
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.5450640309
Subject(s) - porosity , cubic crystal system , nitrobenzene , materials science , thermal diffusivity , diffusion , diamond , thiele modulus , phase (matter) , catalysis , chemistry , thermodynamics , crystallography , composite material , physics , organic chemistry
To evaluate the intraparticle diffusion coefficient, De , of a component in a liquid, it was assumed that the pore structure of a porous catalyst was a space between an assembly of fine particles. This structure has been found for the metal oxide catalysts. The diffusivity ratio, δ (= De/D ), was geometrically estimated in the direction normal to the representative plane (100), (110) or (111) of cubic closed, body centered cubic, simple cubic, or diamond packing of spherical elementary particles. The value δ was found to approximate the porosity ϵ. Larger pore constrictions gave smaller δ/ϵ values. Reaction rates were measured for the hydrogenation of nitrobenzene in ethanol. The efficiency of this evaluation of De was supported by the agreement of the experimental effectiveness factor with the theoretical factor.