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The differentiated effect of NO and NO2 in promoting methane oxidation

Chan, Y. L.; Barnes, F. J.; Bromly, J. H.; Konnov, Alexander LU and Zhang, D. K. (2011) In Proceedings of the Combustion Institute 33. p.441-447
Abstract
It has long been recognised that nitric oxide (NO) and nitrogen dioxide (NO2) can promote the oxidation of methane and other hydrocarbons under various fuel-lean and fuel-rich conditions and a range of temperatures and pressures conditions. However, despite the ease with which NO and NO2 interconvert under the oxidation conditions, the reactions responsible for initiating the oxidation process for methane are different. This is demonstrated experimentally by the different temperature characteristics of the sensitised reaction and supported by kinetic modelling. In this study, the effect of NO/NO2-sensitised oxidation of methane was experimentally studied with two fuel-lean mixtures, viz. 2.5% methane-in-air and 0.05% methane-in-air... (More)
It has long been recognised that nitric oxide (NO) and nitrogen dioxide (NO2) can promote the oxidation of methane and other hydrocarbons under various fuel-lean and fuel-rich conditions and a range of temperatures and pressures conditions. However, despite the ease with which NO and NO2 interconvert under the oxidation conditions, the reactions responsible for initiating the oxidation process for methane are different. This is demonstrated experimentally by the different temperature characteristics of the sensitised reaction and supported by kinetic modelling. In this study, the effect of NO/NO2-sensitised oxidation of methane was experimentally studied with two fuel-lean mixtures, viz. 2.5% methane-in-air and 0.05% methane-in-air mixtures, at atmospheric pressure, over temperature ranges of 823-948 K, and 8731023 K, respectively. Kinetic modelling of the experimental results showed satisfactory agreement and an exhaustive sensitivity analysis was conducted. It was shown through brute-force sensitivity analysis that the difference in key reactions in both NO and NO2 system leads to the observed trend: the effect of NO starts at lower temperatures while NO2 appears to be more potent at higher temperatures. Another salient point emerging from the sensitivity analysis is that the initiation reaction in NO-promoted system was identified to be CH3O2+ NO = CH3O+ NO 2; for NO2-sensitised case, CH4+ NO2 = CH3 + HONO is the most important initiator at lower temperatures while NO2 + O = NO + O-2 and NO2 + HO2 = HONO + O-2 appear to be of prime importance at higher temperatures. (C) 2010 The Combustion Institute. Published by Elsevier Inc. All rights reserved. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
NO, NO2 methane combustion
in
Proceedings of the Combustion Institute
volume
33
pages
441 - 447
publisher
Elsevier
external identifiers
  • wos:000285780200041
  • scopus:78650882560
ISSN
1540-7489
DOI
10.1016/j.proci.2010.05.029
language
English
LU publication?
yes
id
05639d47-4c15-4168-974c-623ecead4f48 (old id 1870151)
date added to LUP
2011-04-06 10:06:56
date last changed
2017-05-28 03:09:22
@article{05639d47-4c15-4168-974c-623ecead4f48,
  abstract     = {It has long been recognised that nitric oxide (NO) and nitrogen dioxide (NO2) can promote the oxidation of methane and other hydrocarbons under various fuel-lean and fuel-rich conditions and a range of temperatures and pressures conditions. However, despite the ease with which NO and NO2 interconvert under the oxidation conditions, the reactions responsible for initiating the oxidation process for methane are different. This is demonstrated experimentally by the different temperature characteristics of the sensitised reaction and supported by kinetic modelling. In this study, the effect of NO/NO2-sensitised oxidation of methane was experimentally studied with two fuel-lean mixtures, viz. 2.5% methane-in-air and 0.05% methane-in-air mixtures, at atmospheric pressure, over temperature ranges of 823-948 K, and 8731023 K, respectively. Kinetic modelling of the experimental results showed satisfactory agreement and an exhaustive sensitivity analysis was conducted. It was shown through brute-force sensitivity analysis that the difference in key reactions in both NO and NO2 system leads to the observed trend: the effect of NO starts at lower temperatures while NO2 appears to be more potent at higher temperatures. Another salient point emerging from the sensitivity analysis is that the initiation reaction in NO-promoted system was identified to be CH3O2+ NO = CH3O+ NO 2; for NO2-sensitised case, CH4+ NO2 = CH3 + HONO is the most important initiator at lower temperatures while NO2 + O = NO + O-2 and NO2 + HO2 = HONO + O-2 appear to be of prime importance at higher temperatures. (C) 2010 The Combustion Institute. Published by Elsevier Inc. All rights reserved.},
  author       = {Chan, Y. L. and Barnes, F. J. and Bromly, J. H. and Konnov, Alexander and Zhang, D. K.},
  issn         = {1540-7489},
  keyword      = {NO,NO2 methane combustion},
  language     = {eng},
  pages        = {441--447},
  publisher    = {Elsevier},
  series       = {Proceedings of the Combustion Institute},
  title        = {The differentiated effect of NO and NO2 in promoting methane oxidation},
  url          = {http://dx.doi.org/10.1016/j.proci.2010.05.029},
  volume       = {33},
  year         = {2011},
}