Revisiting the Kinetics and Thermodynamics of the Low-Temperature Oxidation Pathways of Alkanes: A Case Study of the Three Pentane Isomers

Type
Article

Authors
Bugler, John
Somers, Kieran P.
Silke, Emma J.
Curran, Henry J.

Online Publication Date
2015-04

Print Publication Date
2015-07-16

Date
2015-04

Abstract
© 2015 American Chemical Society. This paper describes our developing understanding of low-temperature oxidation kinetics. We have investigated the ignition of the three pentane isomers in a rapid compression machine over a wide range of temperatures and pressures, including conditions of negative temperature coefficient behavior. The pentane isomers are small alkanes, yet have structures that are complex enough to allow for the application of their kinetic and thermochemical rules to larger molecules. Updates to the thermochemistry of the species important in the low-temperature oxidation of hydrocarbons have been made based on a thorough literature review. An evaluation of recent quantum-chemically derived rate coefficients from the literature pertinent to important low-temperature oxidation reaction classes has been performed, and new rate rules are recommended for these classes. Several reaction classes have also been included to determine their importance with regard to simulation results, and we have found that they should be included when developing future chemical kinetic mechanisms. A comparison of the model simulations with pressure-time histories from experiments in a rapid compression machine shows very good agreement for both ignition delay time and pressure rise for both the first- and second-stage ignition events. We show that revisions to both the thermochemistry and the kinetics are required in order to replicate experiments well. A broader validation of the models with ignition delay times from shock tubes and a rapid compression machine is presented in an accompanying paper. The results of this study enhance our understanding of the combustion of straight- and branched-chained alkanes.

Citation
Bugler J, Somers KP, Silke EJ, Curran HJ (2015) Revisiting the Kinetics and Thermodynamics of the Low-Temperature Oxidation Pathways of Alkanes: A Case Study of the Three Pentane Isomers. The Journal of Physical Chemistry A 119: 7510–7527. Available: http://dx.doi.org/10.1021/acs.jpca.5b00837.

Acknowledgements
The authors would like to acknowledge the support of the Irish Research Council in funding this work. We would also like to thank Drs. Sinéad Burke and Kuiwen Zhang at NUI Galway, Drs. Charlie Westbrook, Bill Pitz, and Marco Mehl at Lawrence Livermore National Laboratory, and Prof. Mani Sarathy at King Abdullah University of Science and Technology for helpful discussions and input.

Publisher
American Chemical Society (ACS)

Journal
The Journal of Physical Chemistry A

DOI
10.1021/acs.jpca.5b00837

PubMed ID
25798548

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