Fiber-Coupled Quartz-Enhanced Photoacoustic Spectroscopy System for Methane and Ethane Monitoring in the Near-Infrared Spectral Range

Abstract

We report on a fiber-coupled, quartz-enhanced photoacoustic spectroscopy (QEPAS) near-IR sensor for sequential detection of methane (CH4 or C1) and ethane (C2H6 or C2) in air. With the aim of developing a lightweight, compact, low-power-consumption sensor suitable for unmanned aerial vehicles (UAVs)-empowered environmental monitoring, an all-fiber configuration was designed and realized. Two laser diodes emitting at 1653.7 nm and 1684 nm for CH4 and C2H6 detection, respectively, were fiber-combined and fiber-coupled to the collimator port of the acoustic detection module. No cross talk between methane and ethane QEPAS signal was observed, and the related peak signals were well resolved. The QEPAS sensor was calibrated using gas samples generated from certified concentrations of 1% CH4 in N2 and 1% C2H6 in N2. At a lock-in integration time of 100 ms, minimum detection limits of 0.76 ppm and 34 ppm for methane and ethane were achieved, respectively. The relaxation rate of CH4 in standard air has been investigated considering the effects of H2O, N2 and O2 molecules. No influence on the CH4 QEPAS signal is expected when the water vapor concentration level present in air varies in the range 0.6–3%.

Vehicle-Deployed Off-Axis Integrated Cavity Output Spectroscopic CH4/C2H6 Sensor System for Mobile Inspection of Natural Gas Leakage

“…A detailed comparison between the demonstrated OA-ICOS sensor system and other previously reported dual-gas CH 4 /C 2 H 6 sensors are summarized in Table . − Though there are differences in the light source and absorption path length (centimeters to tens of kilometers), the developed sensor possesses the lowest detection limit for CH 4 detection, and almost the lowest detection limit for C 2 H 6 detection. Furthermore, this sensor is the only one with the functions of mobile inspection and NG leakage source location at the same time for ppbv-level CH 4 /C 2 H 6 detection.…”

Simultaneous Detection of Methane, Ethane, and Propane by QEPAS Sensors for On-Site Hydrocarbon Characterization and Production Monitoring

“…Being beneficial from the features and advantages, QEPAS has been proposed for field applications in monitoring sour gas (H 2 S, CO 2 ) in an offshore riser, downhole gas analysis, early fire, leak detection, and health-safety-environment monitoring . A typical QEPAS sensor system can be compacted in a small size with light weight, supporting the deployment of the sensor in a portable analyzer, a downhole tool, and an unmanned aerial vehicle. , Several real-world applications of QEPAS have already been reported, , including carbon monoxide (CO) detection in urban area, monitoring of methane (CH 4 ) in landfills, and leak detection of sulfur hexafluoride (SF 6 ) in a vacuum-seal test station for diesel engine injector.…”

“…29 A typical QEPAS sensor system can be compacted in a small size with light weight, supporting the deployment of the sensor in a portable analyzer, a downhole tool, and an unmanned aerial vehicle. 23,34 Several real-world applications of QEPAS have already been reported, 35,36 including carbon monoxide (CO) detection in urban area, monitoring of methane (CH 4 ) in landfills, and leak detection of sulfur hexafluoride (SF 6 ) in a vacuum-seal test station for diesel engine injector.…”

Advances in fiber‐based quartz enhanced photoacoustic spectroscopy for trace gas sensing

“…Schematic diagram of near‐infrared fiber based QEPAS sensing system: (A) multi‐component QEPAS sensing system for CH 4 and NH 3 monitoring 46 ; (B) multi‐component QEPAS sensing system for CH 4 and C 2 H 6 monitoring 47 ; (C) multi‐point QEPAS sensing system. Reproduced from Reference 48, with the permission of AIP Publishing [Color figure can be viewed at wileyonlinelibrary.com]…”

“…Since the transmission of optical fiber provides great convenience for multi‐component gas detection, 2020, Gansergio et al 47 reported a fiber‐based QEPAS system, which can monitor methane and ethane at the same time. The structure of which is shown in Figure 2(B).…”