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Noncatalytic gas‐solid reaction with changing particle size: Unsteady state heat transfer
Author(s) -
Rehmat A.,
Saxena S. C.,
Land R.,
Jonke A. A.
Publication year - 1978
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.5450560308
Subject(s) - particle (ecology) , heat transfer , core (optical fiber) , particle size , thermodynamics , front (military) , mechanics , solid state , chemistry , materials science , physics , meteorology , geology , composite material , oceanography
A mathematical expression for the unsteady state heat balance is derived for a nonisothermal, noncatalytic, first order gas‐solid reaction. The formulation is based on a shrinking core model and takes into account the changing size of the spherical particle during reaction. Thus, the model has two moving boundaries, viz., the reaction front and the external particle diameter which grows or shrinks due to reaction. This complicates the numerical solution considerably. The calculations indicate that both the conversion‐time relationship and core temperature are significantly influenced by the extent of particle growth. The unsteady state and quasi‐steady state analyses lead to somewhat similar results for conversion‐time relationship except for the case where the solid reactant has a large heat capacity. On the other hand, the core temperatures for the two cases differ significantly.