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Role of HOCO Chemistry in Syngas Combustion

Nilsson, E. J K LU and Konnov, A. A. LU (2016) In Energy & Fuels 30(3). p.2443-2457
Abstract

Chemical kinetic mechanisms for simulation of syngas (H2 + CO) combustion are important for development of efficient practical applications, such as gas turbines. A useful syngas mechanism has to be able to accurately predict laminar burning velocities, ignition delays, and oxidation of gas mixtures of varying composition over a range of temperatures and pressures. In the present work, the performance of a new H2/CO combustion mechanism is analyzed. The mechanism is built on reaction rate constants chosen from the most accurate available kinetic data, and this is thoroughly discussed. The mechanism is validated for a wide range of experimental data from the literature. Particular attention is paid to chemistry of... (More)

Chemical kinetic mechanisms for simulation of syngas (H2 + CO) combustion are important for development of efficient practical applications, such as gas turbines. A useful syngas mechanism has to be able to accurately predict laminar burning velocities, ignition delays, and oxidation of gas mixtures of varying composition over a range of temperatures and pressures. In the present work, the performance of a new H2/CO combustion mechanism is analyzed. The mechanism is built on reaction rate constants chosen from the most accurate available kinetic data, and this is thoroughly discussed. The mechanism is validated for a wide range of experimental data from the literature. Particular attention is paid to chemistry of the species HOCO, produced from CO + OH reaction and removed by decomposition or radical reactions. Most available syngas mechanisms do not include HOCO because it is only expected to be of importance at some extreme high-pressure and low-temperature conditions. The species is, however, essential in hierarchically extended mechanisms for small oxygenated hydrocarbons, and its influence on the H2/CO subset of reactions needs to be further understood to ensure accurate mechanism development for a range of fuels. In the present study, it is found that inclusion of the HOCO reaction subset does not alter the model predictions of laminar burning velocities, ignition delay times, or oxidation. Sensitivity analysis reveals that HOCO production, its thermal decomposition, and reaction with O2 are among the 20 most sensitive reactions for conditions of low temperatures and high CO concentrations but with insignificant magnitude of sensitivity compared to that of the major sensitive reactions.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Energy & Fuels
volume
30
issue
3
pages
15 pages
publisher
The American Chemical Society
external identifiers
  • scopus:84961789587
  • wos:000372562800102
ISSN
0887-0624
DOI
10.1021/acs.energyfuels.5b02778
language
English
LU publication?
yes
id
c462c11f-8aac-4a57-9775-0276a87ee5b5
date added to LUP
2016-07-08 11:23:01
date last changed
2017-05-21 04:52:15
@article{c462c11f-8aac-4a57-9775-0276a87ee5b5,
  abstract     = {<p>Chemical kinetic mechanisms for simulation of syngas (H<sub>2</sub> + CO) combustion are important for development of efficient practical applications, such as gas turbines. A useful syngas mechanism has to be able to accurately predict laminar burning velocities, ignition delays, and oxidation of gas mixtures of varying composition over a range of temperatures and pressures. In the present work, the performance of a new H<sub>2</sub>/CO combustion mechanism is analyzed. The mechanism is built on reaction rate constants chosen from the most accurate available kinetic data, and this is thoroughly discussed. The mechanism is validated for a wide range of experimental data from the literature. Particular attention is paid to chemistry of the species HOCO, produced from CO + OH reaction and removed by decomposition or radical reactions. Most available syngas mechanisms do not include HOCO because it is only expected to be of importance at some extreme high-pressure and low-temperature conditions. The species is, however, essential in hierarchically extended mechanisms for small oxygenated hydrocarbons, and its influence on the H<sub>2</sub>/CO subset of reactions needs to be further understood to ensure accurate mechanism development for a range of fuels. In the present study, it is found that inclusion of the HOCO reaction subset does not alter the model predictions of laminar burning velocities, ignition delay times, or oxidation. Sensitivity analysis reveals that HOCO production, its thermal decomposition, and reaction with O<sub>2</sub> are among the 20 most sensitive reactions for conditions of low temperatures and high CO concentrations but with insignificant magnitude of sensitivity compared to that of the major sensitive reactions.</p>},
  author       = {Nilsson, E. J K and Konnov, A. A.},
  issn         = {0887-0624},
  language     = {eng},
  month        = {03},
  number       = {3},
  pages        = {2443--2457},
  publisher    = {The American Chemical Society},
  series       = {Energy & Fuels},
  title        = {Role of HOCO Chemistry in Syngas Combustion},
  url          = {http://dx.doi.org/10.1021/acs.energyfuels.5b02778},
  volume       = {30},
  year         = {2016},
}