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Intraparticle effects in char combustion II. Steady state analysis
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.5450590107
Subject(s) - char , combustion , homogeneous , radiative transfer , boundary layer , steady state (chemistry) , mechanics , thermodynamics , particle (ecology) , boundary value problem , materials science , chemistry , physics , mathematics , mathematical analysis , optics , oceanography , geology
Based on the results of an earlier paper, a model is developed to include the homogeneous reaction in the external boundary layer. It is assumed, consistent with those results, that there is no homogeneous reaction within the particle. A feasibility region is constructed using limiting cases along the lines described there. Under some conditions, the model predicted up to five steady states for a given set of ambient conditions. For large particles, a flame develops in the boundary layer and the main product is CO 2 . Under such conditions, the reaction locus coincides with the double film model. While for small particles, no flame develops and the major product is CO. The solution is sensitive to the type of radiative interaction which obtains. The combustion rate increases with increase in particle temperature until a certain point, then decreases with further increase in temperature, and eventually turns back and increases again. Such behavior has been observed in some rate measurement experiments.