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Non-intrusive, in situ detection of ammonia in hot gas flows with mid-infrared degenerate four-wave mixing at 2.3μm

Sahlberg, A. L. LU ; Hot, D. LU ; Aldén, M. LU and Li, Z. S. LU (2016) In Journal of Raman Spectroscopy 47(9). p.1140-1148
Abstract

We demonstrate non-intrusive, in situ detection of ammonia (NH3) in reactive hot gas flows at atmospheric pressure using mid-infrared degenerate four-wave mixing (IR-DFWM). IR-DFWM excitation scans were performed in the v2+v3 and v1+v2 vibrational bands of NH3 around 2.3μm for gas flow temperatures of 296, 550 and 820K. Simulations based on spectroscopic parameters from the HITRAN database have been compared with the measurements in order to identify the spectral lines, and an absorption spectrum at 296K has also been measured to compare with the IR-DFWM spectra. The signal-to-noise ratio of the IR-DFWM measurement was found to be higher than that of the absorption... (More)

We demonstrate non-intrusive, in situ detection of ammonia (NH3) in reactive hot gas flows at atmospheric pressure using mid-infrared degenerate four-wave mixing (IR-DFWM). IR-DFWM excitation scans were performed in the v2+v3 and v1+v2 vibrational bands of NH3 around 2.3μm for gas flow temperatures of 296, 550 and 820K. Simulations based on spectroscopic parameters from the HITRAN database have been compared with the measurements in order to identify the spectral lines, and an absorption spectrum at 296K has also been measured to compare with the IR-DFWM spectra. The signal-to-noise ratio of the IR-DFWM measurement was found to be higher than that of the absorption measurement. Some spectral lines in the measured IR-DFWM and absorption spectra had no matching lines in the HITRAN simulation. The detection limit of NH3 diluted in N2 with IR-DFWM in this spectral range was estimated at 296, 550 and 820K to be 1.36, 4.87 and 7.06×1016molecules/cm3. The dependence of the NH3 IR-DFWM signal on the quenching properties of the buffer gas flow was investigated by comparing the signals for gas flows of N2, Ar and CO2 with small admixtures of NH3. It was found that the signal dependence on buffer gas was large at room temperature but decreased at elevated temperatures. These results show the potential of IR-DFWM for detection of NH3 in combustion environments.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Ammonia, Degenerate four-wave mixing, Mid-infrared
in
Journal of Raman Spectroscopy
volume
47
issue
9
pages
1140 - 1148
publisher
John Wiley & Sons
external identifiers
  • scopus:84957824730
  • wos:000384079400020
ISSN
0377-0486
DOI
10.1002/jrs.4882
language
English
LU publication?
yes
id
26c487ef-68f7-496c-9df7-a7d41258e3b5
date added to LUP
2016-07-26 10:05:29
date last changed
2017-01-09 13:43:19
@article{26c487ef-68f7-496c-9df7-a7d41258e3b5,
  abstract     = {<p>We demonstrate non-intrusive, in situ detection of ammonia (NH<sub>3</sub>) in reactive hot gas flows at atmospheric pressure using mid-infrared degenerate four-wave mixing (IR-DFWM). IR-DFWM excitation scans were performed in the v<sub>2</sub>+v<sub>3</sub> and v<sub>1</sub>+v<sub>2</sub> vibrational bands of NH<sub>3</sub> around 2.3μm for gas flow temperatures of 296, 550 and 820K. Simulations based on spectroscopic parameters from the HITRAN database have been compared with the measurements in order to identify the spectral lines, and an absorption spectrum at 296K has also been measured to compare with the IR-DFWM spectra. The signal-to-noise ratio of the IR-DFWM measurement was found to be higher than that of the absorption measurement. Some spectral lines in the measured IR-DFWM and absorption spectra had no matching lines in the HITRAN simulation. The detection limit of NH<sub>3</sub> diluted in N<sub>2</sub> with IR-DFWM in this spectral range was estimated at 296, 550 and 820K to be 1.36, 4.87 and 7.06×10<sup>16</sup>molecules/cm<sup>3</sup>. The dependence of the NH<sub>3</sub> IR-DFWM signal on the quenching properties of the buffer gas flow was investigated by comparing the signals for gas flows of N<sub>2</sub>, Ar and CO<sub>2</sub> with small admixtures of NH<sub>3</sub>. It was found that the signal dependence on buffer gas was large at room temperature but decreased at elevated temperatures. These results show the potential of IR-DFWM for detection of NH<sub>3</sub> in combustion environments.</p>},
  author       = {Sahlberg, A. L. and Hot, D. and Aldén, M. and Li, Z. S.},
  issn         = {0377-0486},
  keyword      = {Ammonia,Degenerate four-wave mixing,Mid-infrared},
  language     = {eng},
  number       = {9},
  pages        = {1140--1148},
  publisher    = {John Wiley & Sons},
  series       = {Journal of Raman Spectroscopy},
  title        = {Non-intrusive, in situ detection of ammonia in hot gas flows with mid-infrared degenerate four-wave mixing at 2.3μm},
  url          = {http://dx.doi.org/10.1002/jrs.4882},
  volume       = {47},
  year         = {2016},
}