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Catalyst fragmentation during propylene polymerization: Part II. Microparticle diffusion and reaction effects
Author(s) -
Ferrero Monica A.,
Chiovetta Mario G.
Publication year - 1987
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760271904
Subject(s) - dimensionless quantity , polymerization , materials science , thermodynamics , diffusion , reaction rate , polymer , catalysis , fragmentation (computing) , monomer , a priori and a posteriori , chemical engineering , polymer chemistry , chemistry , organic chemistry , physics , composite material , computer science , philosophy , epistemology , engineering , operating system
A mathematical model is used to predict the behavior of the support/catalyst/polymer macroparticle during the gas phase polymerization of propylene. The problem is focused on the micrograin level of the macroparticle, and the emphasis placed on the combined reaction and diffusion processes taking place in the micropartiele. Particular attention is given to the effect of the main geometry parameter, the size of the catalytic nucleus, on polymerization variables. Fragmentation rate, monomer concentration, and temperature are studied in terms of their dependence on the geometry‐related dimensionless numbers typical of the process. A strong influence of the micrograin size on the commanding process variables is predicted by the model. Fragmentation proves relevant to the overall process and critical to define the time scale of temperature excursions. Micrograin nucleus size are found to be important when computing both maximum temperatures and minimum yields. The model suggests criteria for predicting “a priori” the combination of reaction parameters that will produce a diffusion‐limited reaction regime in the microparticle.