On the validity of thermogravimetric determination of carbon gasification kinetics

Feng, Bo and Bhatia, Suresh K. (2002) On the validity of thermogravimetric determination of carbon gasification kinetics. Chemical Engineering Science, 57 15: 2907-2920. doi:10.1016/S0009-2509(02)00189-6


Author Feng, Bo
Bhatia, Suresh K.
Title On the validity of thermogravimetric determination of carbon gasification kinetics
Journal name Chemical Engineering Science   Check publisher's open access policy
ISSN 0009-2509
Publication date 2002-08
Sub-type Article (original research)
DOI 10.1016/S0009-2509(02)00189-6
Volume 57
Issue 15
Start page 2907
End page 2920
Total pages 14
Editor A.T. Bell
Place of publication London
Publisher Pergamon Press/Elsevier
Collection year 2002
Language eng
Subject C1
250699 Theoretical and Computational Chemistry not elsewhere classified
660101 Coal-electricity
030799 Theoretical and Computational Chemistry not elsewhere classified
Abstract Thermogravimetric analysis has been widely applied in kinetic studies of carbon gasification, with the associated temporal weight change profiles being used to extract kinetic information and to validate gasification models. However the weight change profiles are not always governed by the intrinsic gasification activity because of the effect of chemisorption and its dynamics. In the present work we theoretically determine the criteria under which weight change profiles can be used to determine intrinsic kinetics for CO2 and O2 gasification by examining the region in which the chemisorption dynamics can be assumed pseudo-steady. It is found that the validity of the pseudo-steady assumption depends on the experimental conditions as well as on the initial surface area of carbon. Based on known mechanisms and rate constants an active surface area region is identified within which the steady state assumption is valid and the effect of chemisorption dynamics is negligible. The size of the permissible region is sensitive to the reaction temperature and gas pressure. The results indicate that in some cases the thermogravimetric data should be used with caution in kinetic studies. A large amount of literature on thermogravimetric analyzer determined char gasification kinetics is examined and the importance of chemisorption dynamics for the data assessed.
Keyword Adsorption
Carbon
Energy
Gasification
Kinetics
Reaction engineering
Q-Index Code C1
Additional Notes Received 4 January 2002; revised 11 March 2002; accepted 23 April 2002. Available online 13 August 2002

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
School of Mechanical & Mining Engineering Publications
 
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Created: Tue, 14 Aug 2007, 18:28:43 EST