<i>In situ</i>and wide range quantification of hydrogen sulfide in industrial gases by means of photoacoustic spectroscopy

Szabó, Anna; Mohácsi, Árpád; Gulyas, Gabor; Bozóki, Zoltán; Szabó, Gábor

doi:10.1088/0957-0233/24/6/065501

Cited by 39 publications

(32 citation statements)

References 19 publications

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“…Long term exposure to concentrations below 150 parts per billion (ppb) by volume can cause headaches, irritability, conjunctiva congestion, poor memory and dizziness [1,6]. Hence, there is a need in developing reliable, cost-effective H 2 S sensors, capable for detecting H 2 S at sub-ppm (parts per million) concentration levels for applications in environmental monitoring, human pathologies research and industrial process control [7].…”

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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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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“…[4][5][6] Photoacoustic spectroscopy (PAS) is a very promising method due to its ease of use, relatively low cost and the capability of allowing trace gas measurements at the sub-ppb level. [7][8][9][10] The photoacoustic (PA) technique is based on the detection of sound waves that are generated due to absorption of modulated optical radiation. Quartz tuning forks (QTFs) have shown great potential as sound transducers for PAS and have been increasingly applied to selective and sensitive detection of trace gases since its introduction in 2002.…”

Section: Introductionmentioning

confidence: 99%

Quartz-enhanced photo-acoustic spectroscopy for breath analyses

Petersen¹,

Lamard²,

Feng³

et al. 2017

SPIE Proceedings

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An innovative and novel quartz-enhanced photoacoustic spectroscopy (QEPAS) sensor for highly sensitive and selective breath gas analysis is introduced. The QEPAS sensor consists of two acoustically coupled microresonators (mR) with an off-axis 20 kHz quartz tuning fork (QTF). The complete acoustically coupled mR system is optimized based on finite element simulations and experimentally verified. Due to the very low fabrication costs the QEPAS sensor presents a clear breakthrough in the field of photoacoustic spectroscopy by introducing novel disposable gas chambers in order to avoid cleaning after each test. The QEPAS sensor is pumped resonantly by a nanosecond pulsed single-mode mid-infrared optical parametric oscillator (MIR OPO). Spectroscopic measurements of methane and methanol in the 3.1 µm to 3.7 µm wavelength region is conducted. Demonstrating a resolution bandwidth of 1 cm −1 . An Allan deviation analysis shows that the detection limit at optimum integration time for the QEPAS sensor is 32 ppbv@190s for methane and that the background noise is solely due to the thermal noise of the QTF. Spectra of both individual molecules as well as mixtures of molecules were measured and analyzed. The molecules are representative of exhaled breath gasses that are bio-markers for medical diagnostics.

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“…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]. A fully developed and industry-tailored H 2 S sensor to meet the specific selectivity requirements based on photoacoustic spectroscopy employing dual-channel longitudinal-type resonator cell with capacitive microphone readout and a LOD of 0.5 ppmv is described in [23].…”

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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In situand wide range quantification of hydrogen sulfide in industrial gases by means of photoacoustic spectroscopy

Cited by 39 publications

References 19 publications

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

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

Quartz-enhanced photo-acoustic spectroscopy for breath analyses

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

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