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Intraparticle effects in char combustion. III transient studies
Author(s) -
Srinivas B.,
Amundson Neal R.
Publication year - 1981
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.5450590613
Subject(s) - char , combustion , extinction (optical mineralogy) , mechanics , particle (ecology) , ignition system , radius , boundary layer , particle size , materials science , transient (computer programming) , thermodynamics , chemistry , physics , mineralogy , geology , oceanography , computer security , organic chemistry , computer science , operating system
Unsteady state mass and energy balance equations along with a probabilistic model to predict the surface area evolution, constitute the model developed to study the dynamics of single particle char combustion. The transients and the ignition‐extinction phenomenon are analyzed with the aid of the pseudo‐steady state structure of the problem. There exists a critical particle size, ambient temperature, ambient oxygen concentration and boundary layer thickness above which the particle ignites. There is an optimum particle size for which the burning time is a minimum. Experimentally observed extinction phenomenon of artificially ignited particles is predicted by the model. Also, it is found that the extinction radius decreases with increase in ambient O 2 concentration, which is in qualitative agreement with the experimental results. The model is compared with the simple shrinking core model.