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Measurements of NO concentration in NH3-doped CH4 + air flames using saturated laser-induced fluorescence and probe sampling

Li, Bo LU ; He, Yong; Li, Zhongshan LU and Konnov, Alexander LU (2013) In Combustion and Flame 160(1). p.40-46
Abstract
An experimental study of methane + air flames doped with ammonia (4370 ppm of the fuel) has been performed. The goal of this work was to analyze formation of NOx from fuel-N under well-controlled conditions. The Heat Flux method was used for stabilization of non-stretched adiabatic flames on a perforated plate burner at atmospheric pressure. Laser-saturated fluorescence (LSF) and probe sampling were adopted to measure NO concentrations in the post-flame zone. LSF experiments include two series of measurements: in methane + air flames doped with NO and then in flames doped with NH3. In the lean flames seeded with NO, LSF measurements clearly deviates from the model predictions at higher concentrations of NO seeded, that strongly... (More)
An experimental study of methane + air flames doped with ammonia (4370 ppm of the fuel) has been performed. The goal of this work was to analyze formation of NOx from fuel-N under well-controlled conditions. The Heat Flux method was used for stabilization of non-stretched adiabatic flames on a perforated plate burner at atmospheric pressure. Laser-saturated fluorescence (LSF) and probe sampling were adopted to measure NO concentrations in the post-flame zone. LSF experiments include two series of measurements: in methane + air flames doped with NO and then in flames doped with NH3. In the lean flames seeded with NO, LSF measurements clearly deviates from the model predictions at higher concentrations of NO seeded, that strongly corroborates existence of the lean NO reburning. The modeling accurately predicts [NO] in the neat flame and shows no consumption of NO up to 170 ppm seeded. In (CH4 + NH3) + air mixtures the NO concentrations measured by LSF are in good agreement with the probe sampling results in the whole range of equivalence ratios 0.65<Phi<1.45. No significant impact of the probe sampling on the NOx measurements in the post-flame zone was observed. Present ammonia conversion data are only in agreement with the measurements of Henshaw et al. and disagree with many other earlier experiments. On the other hand they are accurately reproduced by the flame modeling within experimental uncertainties. Therefore the earlier criticism of the models developed by Konnov and by Skreiberg et al. is not substantiated anymore; these mechanisms are capable in predicting ammonia conversion both in lean and in rich flames. Formation of metal complexes in gas cylinders containing ammonia was put forward to explain inconsistencies between present results and earlier experiments. (C) 2012 The Combustion Institute. Published by Elsevier Inc. All rights reserved. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Methane, Flame, Ammonia, NOx
in
Combustion and Flame
volume
160
issue
1
pages
40 - 46
publisher
Elsevier
external identifiers
  • wos:000311771500005
  • scopus:84869092131
ISSN
0010-2180
DOI
10.1016/j.combustflame.2012.10.003
language
English
LU publication?
yes
id
a80a4c9f-50b3-41f6-af1d-29e3b98973a9 (old id 3401007)
date added to LUP
2013-01-29 12:15:55
date last changed
2019-10-23 02:58:49
@article{a80a4c9f-50b3-41f6-af1d-29e3b98973a9,
  abstract     = {An experimental study of methane + air flames doped with ammonia (4370 ppm of the fuel) has been performed. The goal of this work was to analyze formation of NOx from fuel-N under well-controlled conditions. The Heat Flux method was used for stabilization of non-stretched adiabatic flames on a perforated plate burner at atmospheric pressure. Laser-saturated fluorescence (LSF) and probe sampling were adopted to measure NO concentrations in the post-flame zone. LSF experiments include two series of measurements: in methane + air flames doped with NO and then in flames doped with NH3. In the lean flames seeded with NO, LSF measurements clearly deviates from the model predictions at higher concentrations of NO seeded, that strongly corroborates existence of the lean NO reburning. The modeling accurately predicts [NO] in the neat flame and shows no consumption of NO up to 170 ppm seeded. In (CH4 + NH3) + air mixtures the NO concentrations measured by LSF are in good agreement with the probe sampling results in the whole range of equivalence ratios 0.65&lt;Phi&lt;1.45. No significant impact of the probe sampling on the NOx measurements in the post-flame zone was observed. Present ammonia conversion data are only in agreement with the measurements of Henshaw et al. and disagree with many other earlier experiments. On the other hand they are accurately reproduced by the flame modeling within experimental uncertainties. Therefore the earlier criticism of the models developed by Konnov and by Skreiberg et al. is not substantiated anymore; these mechanisms are capable in predicting ammonia conversion both in lean and in rich flames. Formation of metal complexes in gas cylinders containing ammonia was put forward to explain inconsistencies between present results and earlier experiments. (C) 2012 The Combustion Institute. Published by Elsevier Inc. All rights reserved.},
  author       = {Li, Bo and He, Yong and Li, Zhongshan and Konnov, Alexander},
  issn         = {0010-2180},
  keyword      = {Methane,Flame,Ammonia,NOx},
  language     = {eng},
  number       = {1},
  pages        = {40--46},
  publisher    = {Elsevier},
  series       = {Combustion and Flame},
  title        = {Measurements of NO concentration in NH3-doped CH4 + air flames using saturated laser-induced fluorescence and probe sampling},
  url          = {http://dx.doi.org/10.1016/j.combustflame.2012.10.003},
  volume       = {160},
  year         = {2013},
}