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Effect of operational parameters on combustion and emissions in an industrial gas turbine combustor

Emami, Mohsen D.; Shahbazian, Hamidreza LU and Sunden, Bengt LU (2019) In Journal of Energy Resources Technology, Transactions of the ASME 141(1).
Abstract

Enhancing a combustion system requires increased combustion efficiency, fuel savings, and reduction of combustion emissions. In this paper, the combustion of CH4 in the combustor of an industrial gas turbine is studied and NO and CO formation/emission is simulated numerically. The objective of the current work is to investigate the influence of combustive parameters and varying the percentage of distributed air flow rate via burning, recirculation, and dilution zone on the reactive flow characteristics, NOx and CO emissions. The governing equations of mass, momentum, energy, turbulence quantities Renormalized group (RNG) (k-ε), mixture fraction and its variance are solved by the finite volume method. The formation... (More)

Enhancing a combustion system requires increased combustion efficiency, fuel savings, and reduction of combustion emissions. In this paper, the combustion of CH4 in the combustor of an industrial gas turbine is studied and NO and CO formation/emission is simulated numerically. The objective of the current work is to investigate the influence of combustive parameters and varying the percentage of distributed air flow rate via burning, recirculation, and dilution zone on the reactive flow characteristics, NOx and CO emissions. The governing equations of mass, momentum, energy, turbulence quantities Renormalized group (RNG) (k-ε), mixture fraction and its variance are solved by the finite volume method. The formation and emission of NOx is numerically simulated in a postprocessing fashion, due to the low concentration of the pollutants as compared to the main combustion species. The present work focuses on different physical mechanisms of NOx formation. The thermal-NOx and prompt-NOx mechanism are considered for modeling the NOx source term in the transport equation. Results show that in a gaseous-fueled combustor, the thermal NOx is the dominant mechanism for NOx formation. Particularly, the simulation provides more insight into the correlation between the maximum combustor temperature, exhaust average temperatures, and the thermal NO concentration. Results indicate that the exhaust temperature and NOx concentration decrease while the excess air factor increases. Moreover, results demonstrate that as the combustion air temperature increases, the combustor temperature increases and the thermal NOx concentration increases dramatically. Furthermore, results demonstrate that the NO concentration at the combustor exit is at maximum value in a swirl angle of 55 deg and a gradual rise in the NOx concentration is detected as the combustion fuel temperature increases. In addition, results demonstrate that the air distribution of the first case at laboratory conditions is optimal where the mass fractions of NO and CO are minimum.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Air flow distribution, Chemical kinetic, Gas turbine combustion, NO, Pollutant
in
Journal of Energy Resources Technology, Transactions of the ASME
volume
141
issue
1
publisher
American Society Of Mechanical Engineers (ASME)
external identifiers
  • scopus:85054930346
ISSN
0195-0738
DOI
10.1115/1.4040532
language
English
LU publication?
yes
id
dede5763-dd21-41f6-b81b-d86b66ce9002
date added to LUP
2018-10-26 13:15:46
date last changed
2018-10-26 13:15:46
@article{dede5763-dd21-41f6-b81b-d86b66ce9002,
  abstract     = {<p>Enhancing a combustion system requires increased combustion efficiency, fuel savings, and reduction of combustion emissions. In this paper, the combustion of CH<sub>4</sub> in the combustor of an industrial gas turbine is studied and NO and CO formation/emission is simulated numerically. The objective of the current work is to investigate the influence of combustive parameters and varying the percentage of distributed air flow rate via burning, recirculation, and dilution zone on the reactive flow characteristics, NO<sub>x</sub> and CO emissions. The governing equations of mass, momentum, energy, turbulence quantities Renormalized group (RNG) (k-ε), mixture fraction and its variance are solved by the finite volume method. The formation and emission of NO<sub>x</sub> is numerically simulated in a postprocessing fashion, due to the low concentration of the pollutants as compared to the main combustion species. The present work focuses on different physical mechanisms of NO<sub>x</sub> formation. The thermal-NO<sub>x</sub> and prompt-NO<sub>x</sub> mechanism are considered for modeling the NO<sub>x</sub> source term in the transport equation. Results show that in a gaseous-fueled combustor, the thermal NO<sub>x</sub> is the dominant mechanism for NO<sub>x</sub> formation. Particularly, the simulation provides more insight into the correlation between the maximum combustor temperature, exhaust average temperatures, and the thermal NO concentration. Results indicate that the exhaust temperature and NO<sub>x</sub> concentration decrease while the excess air factor increases. Moreover, results demonstrate that as the combustion air temperature increases, the combustor temperature increases and the thermal NO<sub>x</sub> concentration increases dramatically. Furthermore, results demonstrate that the NO concentration at the combustor exit is at maximum value in a swirl angle of 55 deg and a gradual rise in the NO<sub>x</sub> concentration is detected as the combustion fuel temperature increases. In addition, results demonstrate that the air distribution of the first case at laboratory conditions is optimal where the mass fractions of NO and CO are minimum.</p>},
  articleno    = {012202},
  author       = {Emami, Mohsen D. and Shahbazian, Hamidreza and Sunden, Bengt},
  issn         = {0195-0738},
  keyword      = {Air flow distribution,Chemical kinetic,Gas turbine combustion,NO,Pollutant},
  language     = {eng},
  number       = {1},
  publisher    = {American Society Of Mechanical Engineers (ASME)},
  series       = {Journal of Energy Resources Technology, Transactions of the ASME},
  title        = {Effect of operational parameters on combustion and emissions in an industrial gas turbine combustor},
  url          = {http://dx.doi.org/10.1115/1.4040532},
  volume       = {141},
  year         = {2019},
}