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An experimental technique for determining the significance of intraparticle diffusion in an aging catalyst
Author(s) -
Best Donald A.,
Wojciechowski Bohdan W.
Publication year - 1976
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.5450540313
Subject(s) - catalysis , diffusion , cumene , fluid catalytic cracking , chemistry , particle size , zeolite , range (aeronautics) , materials science , cracking , chemical engineering , thermodynamics , composite material , organic chemistry , physics , engineering
The effects of simultaneous decay and diffusion on a first order reactiion have been investigated. Two limiting types of behaviour are observed. In the first, cumulative conversion on diffusion limited catalysts is shown to behave in a manner opposite to that expected if the catalyst were non‐aging, in that conversion decreases with decreasing particle size. The other extreme shows behaviour consistent with that observed on a non‐decaying catalyst; that is, conversion increases with decreasing catalyst size. Experimental evidence for such behaviour is observed with cumene cracking and gas oil cracking, both on zeolite catalysts. As a consequence of the above observations, it is proposed that a new test involving experimentation at constant cat/oil ratio and over a range of space velocities be used to determine the significance of intraparticle diffusion on a catalyst subject to decay.