The use of DTA to study spontanceous ignition of cellulose

Horrocks, Richard ORCID: 0000-0003-1431-058X, Davies, D. and Greenhalgh, M. (1985) The use of DTA to study spontanceous ignition of cellulose. Fire and Materials, 9 (2). pp. 57-64. ISSN 0308-0501

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Official URL: https://onlinelibrary.wiley.com/journal/10991018

Abstract

The use of differential thermal analysis has enabled spontaneous ignition behaviour of cotton cellulose to be investigate. The temperature. Ti, at which the onset of spontaneous ignition occurs is recorded as a function of the oxygen concentration of the flowing oxygen‐nitrogen atmosphere to which the cellulose sample is exposed in the DTA furnace, when heated at a defined heating rate. The dependence of Ti, on heating rate has enabled the activation energy, Ep, of the rate‐determining flammable pyrolysis product reaction to the determined using both a previously derived simple kinetic model and the technique of Ozawa. Ep, increases from a lower limiting value of 112 kJ mol−1 at zero oxygen concentration to an asymptote value of 169 kJ mol−1 at oxygen volume concentrations above 30%. This effect is described in terms of oxygen catalysis of competing pyrolysis routes. At a given heating rate, increased oxygen concentration reduces Ti. A plot of 1/Ti versus In [O2] gives two liner regions which intersect at an oxygen concentration of about 20%, suggesting that two combustion mechanisms exist, one above and the other below this value. Below this concentration, which is similar to the conventional limiting oxygen for cellulose, significant char remains, suggesting that ignition of gaseous products only occurs. If the difference in slopes is sttributed to the variations in Ep with oxygen concentration, then a value for the activation energy of gaseous product oxidation, Eox = 215 kJ mol−1 is derived.

Item Type: Article
Additional Information: A version of this paper was also presented at Interflam 82, 30th March, 1982 University of Surrey
Divisions: University of Bolton Research Centres > Institute for Materials Research and Innovation
Depositing User: Tracey Gill
Date Deposited: 09 Aug 2018 11:21
Last Modified: 09 Aug 2018 11:42
Identification Number: 10.1002/fam.810090202
URI: http://ubir.bolton.ac.uk/id/eprint/1836

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