Nitric oxide pollutant formation in high hydrogen content (HHC)syngas flames
Nitric oxide pollutant formation in high hydrogen content (HHC)syngas flames
Three-dimensional direct numerical simulations (DNS) of high hydrogen content (HHC) syngas nonpremixed jet flames with a Reynolds number of Re=6000 have been carried out to study the nitric oxide (NO) pollutant formation. The detailed chemistry employed is the GRI 3.0 updated with the influence of the NCN radical chemistry using flamelet generated manifolds (FGM). Preferential diffusion effects have been considered via FGM tabulation and the reaction progress variable transport equation. The DNS based quantitative results indicate a strong correlation between the flame temperature and NO concentration for the pure hydrogen flame, in which NO formation is mainly characterised by the Zeldovich mechanism. The results also indicate a rapid decrease of maximum NO values in hydrogen/carbon monoxide syngas mixtures due to lower temperatures associated with the CO-dilution into hydrogen. Results on NO formation routes in hydrogen-carbon monoxide syngas flames show that while the Zeldovich mechanism dominates the NO formation at low strain rates, the high NO formation rate at high strain rates is entirely caused by the NNH mechanism. We also found that the Fenimore mechanism has a least contribution on NO formation in hydrogen-carbon monoxide syngas flames due to absence of CH radicals in the oxidation of CO. It is found that, due to preferential diffusion, NO concentration exhibits higher values near the flame base depending on the hydrogen content in hydrogen-carbon monoxide syngas fuel mixture.
syngas, direct numerical simulation, preferential diffusion, zeldovich mechanism, NNH mechanism
13621-13634
Ranga Dinesh, K.K.J.
6454b22c-f505-40f9-8ad4-a1168e8f87cd
van Oijen, J.
72021a7c-153e-43f9-b411-81492b13afd5
Luo, K.
27114d6d-80ed-4c5a-ae14-d7f3e3b8ac16
Jiang, X.
008a11fa-f330-4355-b5c6-2878d1ab0f5c
19 October 2015
Ranga Dinesh, K.K.J.
6454b22c-f505-40f9-8ad4-a1168e8f87cd
van Oijen, J.
72021a7c-153e-43f9-b411-81492b13afd5
Luo, K.
27114d6d-80ed-4c5a-ae14-d7f3e3b8ac16
Jiang, X.
008a11fa-f330-4355-b5c6-2878d1ab0f5c
Ranga Dinesh, K.K.J., van Oijen, J., Luo, K. and Jiang, X.
(2015)
Nitric oxide pollutant formation in high hydrogen content (HHC)syngas flames.
International Journal of Hydrogen Energy, 40 (39), .
(doi:10.1016/j.ijhydene.2015.08.068).
Abstract
Three-dimensional direct numerical simulations (DNS) of high hydrogen content (HHC) syngas nonpremixed jet flames with a Reynolds number of Re=6000 have been carried out to study the nitric oxide (NO) pollutant formation. The detailed chemistry employed is the GRI 3.0 updated with the influence of the NCN radical chemistry using flamelet generated manifolds (FGM). Preferential diffusion effects have been considered via FGM tabulation and the reaction progress variable transport equation. The DNS based quantitative results indicate a strong correlation between the flame temperature and NO concentration for the pure hydrogen flame, in which NO formation is mainly characterised by the Zeldovich mechanism. The results also indicate a rapid decrease of maximum NO values in hydrogen/carbon monoxide syngas mixtures due to lower temperatures associated with the CO-dilution into hydrogen. Results on NO formation routes in hydrogen-carbon monoxide syngas flames show that while the Zeldovich mechanism dominates the NO formation at low strain rates, the high NO formation rate at high strain rates is entirely caused by the NNH mechanism. We also found that the Fenimore mechanism has a least contribution on NO formation in hydrogen-carbon monoxide syngas flames due to absence of CH radicals in the oxidation of CO. It is found that, due to preferential diffusion, NO concentration exhibits higher values near the flame base depending on the hydrogen content in hydrogen-carbon monoxide syngas fuel mixture.
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Accepted/In Press date: 21 August 2015
e-pub ahead of print date: 9 September 2015
Published date: 19 October 2015
Keywords:
syngas, direct numerical simulation, preferential diffusion, zeldovich mechanism, NNH mechanism
Organisations:
Energy & Climate Change Group
Identifiers
Local EPrints ID: 383310
URI: http://eprints.soton.ac.uk/id/eprint/383310
ISSN: 0360-3199
PURE UUID: 966b3b37-a7ce-46b6-94a8-20a6a505dad2
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Date deposited: 28 Oct 2015 10:34
Last modified: 15 Mar 2024 03:47
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Author:
J. van Oijen
Author:
K. Luo
Author:
X. Jiang
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