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Ultraviolet Absorption Cross-Sections of Ammonia at Elevated Temperatures for Nonintrusive Quantitative Detection in Combustion Environments

Weng, Wubin LU ; Li, Shen LU ; Aldén, Marcus LU and Li, Zhongshan LU (2021) In Applied Spectroscopy 75(9). p.1168-1177
Abstract

Ammonia (NH3) is regarded as an important nitrogen oxides (NOx) precursor and also as an effective reductant for NOx removal in energy utilization through combustion, and it has recently become an attractive non-carbon alternative fuel. To have a better understanding of thermochemical properties of NH3, accurate in situ detection of NH3 in high temperature environments is desirable. Ultraviolet (UV) absorption spectroscopy is a feasible technique. To achieve quantitative measurements, spectrally resolved UV absorption cross-sections of NH3 in hot gas environments at different temperatures from 295 K to 590 K were experimentally measured for the first time. Based on the experimental results,... (More)

Ammonia (NH3) is regarded as an important nitrogen oxides (NOx) precursor and also as an effective reductant for NOx removal in energy utilization through combustion, and it has recently become an attractive non-carbon alternative fuel. To have a better understanding of thermochemical properties of NH3, accurate in situ detection of NH3 in high temperature environments is desirable. Ultraviolet (UV) absorption spectroscopy is a feasible technique. To achieve quantitative measurements, spectrally resolved UV absorption cross-sections of NH3 in hot gas environments at different temperatures from 295 K to 590 K were experimentally measured for the first time. Based on the experimental results, vibrational constants of NH3 were determined and used for the calculation of the absorption cross-section of NH3 at high temperatures above 590 K using the PGOPHER software. The investigated UV spectra covered the range of wavelengths from 190 nm to 230 nm, where spectral structures of the (Formula presented.) transition of NH3 in the umbrella bending mode, v2, were recognized. The absorption cross-section was found to decrease at higher temperatures. For example, the absorption cross-section peak of the (6, 0) vibrational band of NH3 decreases from ∼2 × 10−17 to ∼0.5 × 10−17 cm2/molecule with the increase of temperature from 295 K to 1570 K. Using the obtained absorption cross-section, in situ nonintrusive quantification of NH3 in different hot gas environments was achieved with a detection limit varying from below 10 parts per million (ppm) to around 200 ppm as temperature increased from 295 K to 1570 K. The quantitative measurement was applied to an experimental investigation of NH3 combustion process. The concentrations of NH3 and nitric oxide (NO) in the post flame zone of NH3–methane (CH4)–air premixed flames at different equivalence ratios were measured.

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author
; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Ammonia, combustion, high temperature, quantitative optical measurement, ultraviolet absorption cross-section, ultraviolet absorption spectroscopy, UV absorption cross-section, UV absorption spectroscopy
in
Applied Spectroscopy
volume
75
issue
9
pages
1168 - 1177
publisher
Society for Applied Spectroscopy
external identifiers
  • scopus:85100521444
  • pmid:33464157
ISSN
0003-7028
DOI
10.1177/0003702821990445
language
English
LU publication?
yes
id
72f93c29-3db8-4d3a-a374-aa00ed45ac86
date added to LUP
2021-02-25 07:40:59
date last changed
2024-12-13 03:45:52
@article{72f93c29-3db8-4d3a-a374-aa00ed45ac86,
  abstract     = {{<p>Ammonia (NH<sub>3</sub>) is regarded as an important nitrogen oxides (NOx) precursor and also as an effective reductant for NOx removal in energy utilization through combustion, and it has recently become an attractive non-carbon alternative fuel. To have a better understanding of thermochemical properties of NH<sub>3</sub>, accurate in situ detection of NH<sub>3</sub> in high temperature environments is desirable. Ultraviolet (UV) absorption spectroscopy is a feasible technique. To achieve quantitative measurements, spectrally resolved UV absorption cross-sections of NH<sub>3</sub> in hot gas environments at different temperatures from 295 K to 590 K were experimentally measured for the first time. Based on the experimental results, vibrational constants of NH<sub>3</sub> were determined and used for the calculation of the absorption cross-section of NH<sub>3</sub> at high temperatures above 590 K using the PGOPHER software. The investigated UV spectra covered the range of wavelengths from 190 nm to 230 nm, where spectral structures of the (Formula presented.) transition of NH<sub>3</sub> in the umbrella bending mode, v<sub>2</sub>, were recognized. The absorption cross-section was found to decrease at higher temperatures. For example, the absorption cross-section peak of the (6, 0) vibrational band of NH<sub>3</sub> decreases from ∼2 × 10<sup>−17</sup> to ∼0.5 × 10<sup>−17</sup> cm<sup>2</sup>/molecule with the increase of temperature from 295 K to 1570 K. Using the obtained absorption cross-section, in situ nonintrusive quantification of NH<sub>3</sub> in different hot gas environments was achieved with a detection limit varying from below 10 parts per million (ppm) to around 200 ppm as temperature increased from 295 K to 1570 K. The quantitative measurement was applied to an experimental investigation of NH<sub>3</sub> combustion process. The concentrations of NH<sub>3</sub> and nitric oxide (NO) in the post flame zone of NH<sub>3</sub>–methane (CH<sub>4</sub>)–air premixed flames at different equivalence ratios were measured.</p>}},
  author       = {{Weng, Wubin and Li, Shen and Aldén, Marcus and Li, Zhongshan}},
  issn         = {{0003-7028}},
  keywords     = {{Ammonia; combustion; high temperature; quantitative optical measurement; ultraviolet absorption cross-section; ultraviolet absorption spectroscopy; UV absorption cross-section; UV absorption spectroscopy}},
  language     = {{eng}},
  month        = {{01}},
  number       = {{9}},
  pages        = {{1168--1177}},
  publisher    = {{Society for Applied Spectroscopy}},
  series       = {{Applied Spectroscopy}},
  title        = {{Ultraviolet Absorption Cross-Sections of Ammonia at Elevated Temperatures for Nonintrusive Quantitative Detection in Combustion Environments}},
  url          = {{https://lup.lub.lu.se/search/files/119436476/Weng_Appl_Spec_75_2021.pdf}},
  doi          = {{10.1177/0003702821990445}},
  volume       = {{75}},
  year         = {{2021}},
}