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Kinetic parameters associated with self-heating of New Zealand coals under adiabatic conditions

Published online by Cambridge University Press:  05 July 2018

B. B. Beamish ,
J. D. St. George  and
M. A. Barakat
B. B. Beamish*
Affiliation:
Division of Mining and Minerals Process Engineering, The University of Queensland, Brisbane 4072, Australia
J. D. St. George
Affiliation:
Department of Civil and Resource Engineering, The University of Auckland, Auckland, New Zealand
M. A. Barakat
Affiliation:
Department of Civil and Resource Engineering, The University of Auckland, Auckland, New Zealand
*
* E-mail: [email protected]
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Abstract

Adiabatic self-heating tests were carried out on five New Zealand coal samples ranging in rank from lignite to high-volatile bituminous. Kinetic parameters of oxidation were obtained from the self-heating curves assuming Arrhenius behaviour. The activation energy E (kJ mol–1) and the pre-exponential factor A (s–1) were determined in the temperature range of 70–140°C. The activation energy exhibited a definite rank relationship with a minimum E of 55 kJ mol–1 occurring at a Suggate rank of ∼6.2 corresponding to subbituminous C. Either side of this rank there was a noticeable increase in the activation energy indicating lower reactivity of the coal. A similar rank trend was also observed in the R70 self-heating rate index values that were taken from the initial portion of the self-heating curve from 40 to 70°C. From these results it is clear that the adiabatic method is capable of providing reliable kinetic parameters of coal oxidation.

Keywords

coalself-heatingadiabatic ovenactivation energy.
Type
Research Article
Information
Mineralogical Magazine , Volume 67 , Issue 4 , August 2003 , pp. 665 - 670
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2003

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