H2S trace concentration measurements using off-axis integrated cavity output spectroscopy in the near-infrared

Chen, W.; Kosterev, Anatoliy A.; Tittel, Frank K.; Gao, Xiaoming; Zhao, Weixiong

doi:10.1007/s00340-007-2858-5

Cited by 50 publications

(31 citation statements)

References 16 publications

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“…This sensitivity is from 2 to 10 times better comparing to results reported for near-infrared systems that use QEPAS, integrated cavity output spectroscopy, WMS, or CLaDS. [2][3][4][5] It outperforms most previously demonstrated setups that also use QCLs in 7-to 8.2-μm range [10][11][12] and is comparable to a recently demonstrated system operating at 8.018 μm. 19 Modified two-point deviation analysis reveals that a basic WMS system with no active line-locking can achieve better than 400 ppbv accuracy over extended operation times spanning above 1000 s, which is an ideal solution for a cost-effective technology required for industrial safety monitoring applications.…”

Section: Discussionsupporting

confidence: 56%

“…2 Minimum detectable concentration of ∼220 ppbv (1σ) for a 2-s averaging time was obtained through the application of an off-axis integrated cavity output spectroscopy (OA-ICOS) at 1571.6 nm. 3 Several groups also performed studies of stand-off detection of H 2 S in this spectral region by implementing wavelength modulation spectroscopy (WMS) at 1.59 μm (Ref. 4) with a detection limit at 50 ppmv × m level at 1-s integration time, or chirped laser dispersion spectroscopy (CLaDS) at 1574.5 nm with a detection limit at ∼225 ppmv × m (tested with an open-path multipass cell).…”

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confidence: 99%

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Quantum cascade laser-based analyzer for hydrogen sulfide detection at sub-parts-per-million levels

et al. 2017

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Abstract. Due to its high toxicity, monitoring of hydrogen sulfide (H 2 S) concentration is essential in many industrial sites (such as natural gas extraction sites, petroleum refineries, geothermal power plants, or waste water treatment facilities), which require sub-parts-per-million sensitivities. We report on a quantum cascade laserbased spectroscopic system for detection of H 2 S in the midinfrared at ∼7.2 μm. We present a sensor design utilizing Herriott multipass cell and a wavelength modulation spectroscopy to achieve a detection limit of 140 parts per billion for 1-s integration time.

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Section: Discussionsupporting

confidence: 56%

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confidence: 99%

Quantum cascade laser-based analyzer for hydrogen sulfide detection at sub-parts-per-million levels

et al. 2017

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“…Hydrogen sulfide (H 2 S), one of the major air pollutants globally, is a colorless, toxic, flammable gas, which is mainly released into the atmosphere by burning of natural gas, fossil fuel, and other sulfur-bearing fuels as well as volcanic eruptions [1]. H 2 S can also be found in well Page 4 of 36 A c c e p t e d M a n u s c r i p 4 water ( occurs either naturally in well water or due to the presence of sulphate-reducing bacteria) and anywhere elemental sulfur is exposed to organic material [2] as well as sewers, swamps and waste treatment industries [3].…”

Section: Introductionmentioning

confidence: 99%

Enhanced near-infrared QEPAS sensor for sub-ppm level H2S detection by means of a fiber amplified 1582 nm DFB laser

Dong

Zheng

et al. 2015

Sensors and Actuators B: Chemical

101

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Enhanced near-infrared QEPAS sensor for sub-ppm level H 2 S detection by means of a fiber amplified 1582nm DFB laser, Sensors and Actuators B: Chemical (2015), http://dx. Abstract:A power-boosted quartz-enhanced photoacoustic spectroscopy (QEPAS) sensor is developed for sub-ppm H 2 S trace-gas detection in the near-infrared spectral region. The sensor is based on off-beam QEPAS with an erbium-doped fiber amplified 1582 nm distributed feedback (DFB) laser. The offset of the sensor floor noise caused by stray light and gas flow can be removed by an electrical modulation cancellation method, which lowers the noise to the theoretical thermal noise level. The sensor was optimized in terms of gas pressure and current modulation A c c e p t e d M a n u s c r i p 2 depth for H 2 S detection at 6320.6 cm -1 . The linearity of the sensor response to the laser power and H 2 S concentration confirms that saturation does not occur. With ~ 1.4 W optical excitation power and 67 sec averaging time, a H 2 S detection sensitivity of 142 ppbv (parts per billion by volume) is achieved at atmospheric pressure and room temperature, which is the best value, reported in the literature so far for H 2 S QEPAS sensors. A side-by-side sensitivity comparison for different sensor systems is also reported.

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“…The path length can be reduced by using wavelength modulation or balanced detection approaches, which furthermore improve the sensitivity of TDLAS sensors [17][18][19]. Although the detection of H 2 S concentrations of several ppb has been demonstrated by employing integrated cavity output spectroscopy approach (ICOS) [20], such sensitivities are difficult to obtain in field measurements as the robustness of this kind of systems remains limited [21,22]. Possible alternatives to bulky multipass absorption or delicate sensing schemes based on cavity spectroscopy are photoacoustic H 2 S measurement strategies [23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Cantilever-enhanced photoacoustic detection of hydrogen sulfide (H2S) using NIR telecom laser sources near 1.6 µm

Moser

Lendl

2016

Appl. Phys. B

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concentrations as low as 500 pptv manifesting in the characteristic odor of rotten eggs can already be detected by the human olfactory sense, the total loss of olfactory sensation starts at 150-200 ppmv [3]. Because of the wide occurrence of H 2 S in industrial processes and its often negative impact on process stabilities and product quality, its concentration needs to be tightly monitored. Furthermore, safety considerations and legal concentration limits also necessitate the accurate determination of H 2 S levels. In practice, concentrations ranging from sub-ppm levels at low pressures to several per cents at atmospheric conditions need to be monitored. Due to such diverse requirements, H 2 S analyzers based on different measurement technologies have been developed and are in industrial use. Apart from spectroscopic techniques based on absorption measurements, a range of other analytical techniques such as pulsed UV fluorescence [4], sulfur chemiluminescence [5], colorimetry employing a lead acetate tape [6], flame photometry as detector in gas chromatography [7] as well as electrochemical detection techniques ranging from potentiometric, galvanic, coulometric and amperometric detection [8] is frequently employed. It is interesting to note that in the petrochemical industry the lead acetate tape method is still in frequent use. Also, gas chromatographic methods are popular as they can be used to detect several components almost simultaneously, but this technique requires preparation and extraction of the sample gas leading to a time-consuming measurement. A general drawback of nonspectroscopic techniques is the fact that they do not allow for direct measurements. This, however, also applies to H 2 S detection based on UV fluorescence as this technique requires sample combustion as well as detection by chemoluminescence, where addition of reagents is required.Most of the spectroscopic techniques are based on the detection of the absorption spectrum of the molecules in Abstract Sensitive detection of hydrogen sulfide (H 2 S) at different pressure levels using a cantilever-enhanced photoacoustic detector in combination with a telecom NIR L-band laser source is reported. Amplitude and wavelength modulation schemes for photoacoustic signal generation are compared. A detection limit (3σ) of 8 ppmv was achieved for amplitude modulation mode with a 50-s averaging time for the H 2 S absorption near 1.6 µm. As compared to simulated spectra, the cantilever-enhanced photoacoustic detection approach in combination with the sufficiently stable and narrow bandwidth NIR laser is able to reproduce the rotationally resolved H 2 S spectrum at low pressures of 300 mbar.

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H2S trace concentration measurements using off-axis integrated cavity output spectroscopy in the near-infrared

Cited by 50 publications

References 16 publications

Quantum cascade laser-based analyzer for hydrogen sulfide detection at sub-parts-per-million levels

Quantum cascade laser-based analyzer for hydrogen sulfide detection at sub-parts-per-million levels

Enhanced near-infrared QEPAS sensor for sub-ppm level H2S detection by means of a fiber amplified 1582 nm DFB laser

Cantilever-enhanced photoacoustic detection of hydrogen sulfide (H2S) using NIR telecom laser sources near 1.6 µm

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