The calibration and deployment of a low-cost methane sensor
The calibration and deployment of a low-cost methane sensor
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DOI：
10.1016/j.atmosenv.2020.117440
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发表时间：
2020-06-01
影响因子：
5
通讯作者：
Riddick, John C.
中科院分区：
文献类型：
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作者：
Riddick, Stuart N.;Mauzerall, Denise L.;Riddick, John C.
自1850年以来，甲烷(CH4)的大气混合比翻了一番。甲烷是一种强有力的温室气体。这一增长与人为来源排放量的增加直接相关。必须有一种廉价的手段来确定和监测甲烷排放源，并评估缓解战略的效果。然而，寻找可靠、低成本、易于校准的适合用途的传感器是具有挑战性的。最近的一项研究表明，来自低功率、低成本的甲烷传感器(Figaro TG52600)的甲烷混合比数据与高精度传感器在混合比为1.85ppm至2ppm时测得的甲烷混合比符合得很好。为了研究这种低成本传感器是否可以用于测量典型的环境甲烷混合比，作为概念证明，我们在受控的实验室条件下使用了TG52600和Los Gatos超便携温室气体分析仪(Ugga)。然后，我们通过在一个陆上天然气终端附近部署TG52600来计算2018年5月至7月的排放量，从而探索了传感器的长期可靠性。我们的初步研究表明，以前发表的线性算法无法将TG52600的输出转换为Ugga测量的CH4混合比率。然而，我们得出了一个非线性经验关系，可以用来可靠地将TG52600装置的输出转换为1.85-5.85ppm范围内的CH4混合比，从而使高精度仪器的输出达到+/-0.01ppm。我们的研究表明，TG52600可以用来连续测量天然气终端顺风向三个月内甲烷混合比从1.82到5.40ppm的变化。采用简化的高斯烟羽模型，这些混合比对应的排放通量范围为0-238g CH(4)S(-1)，平均排放量为9.6g CH(4)S(-1)和1.6g CH(4)S(-1)来自退役的南航站楼。我们在这里的工作证明了利用低成本传感器在接近环境背景水平的浓度下检测甲烷泄漏的可行性，只要该设备定期使用准确的参考仪器进行校准。拥有一个由这种低成本甲烷传感器组成的广泛部署的网络，将有助于改进对各种甲烷排放的识别、监测和缓解。
Since 1850 the atmospheric mixing ratio of methane (CH4), a potent greenhouse gas, has doubled. This increase is directly linked to an escalation in emissions from anthropogenic sources. An inexpensive means to identify and monitor CH4 emission sources and evaluate the efficacy of mitigation strategies is essential. However, sourcing reliable, low-cost, easy-to-calibrate sensors that are fit for purpose is challenging. A recent study showed that CH4 mixing ratio data from a low-power, low-cost CH4 sensor (Figaro TG52600) agreed well with CH4 mixing ratios measured by a high precision sensor at mixing ratios between 1.85 ppm and 2 ppm. To investigate, as a proof of concept, if this low-cost sensor could be used to measure typical ambient CH4 mixing ratios, we operated a TG52600 in conjunction with a Los Gatos Ultra-portable Greenhouse Gas Analyzer (UGGA) in controlled laboratory conditions. We then explored the sensor's long-term reliability by deploying the TG52600 near an onshore gas terminal to calculate emissions from May to July 2018. Our initial studies showed that previously published linear algorithms could not convert TG52600 output to CH4 mixing ratios measured by the UGGA. However, we derived a non-linear empirical relationship that could be used to reliably convert the output of a TG52600 unit to CH4 mixing ratios over a range of 1.85-5.85 ppm that agree to a high-precision instrument output to +/- 0.01 ppm. Our study showed that the TG52600 could be used to continuously measure variability in CH4 mixing ratios from 1.82 to 5.40 ppm for three months downwind of the gas terminal. Using a simplified Gaussian Plume approach, these mixing ratios correspond to an emission flux range of 0-238 g CH(4)s(-1), with average emission of 9.6 g CH(4)s(-1) from the currently active North Terminal and 1.6 g CH(4)s(-1) from the decommissioned South Terminal. Our work here demonstrates the feasibility of utilizing a low-cost sensor to detect methane leakage at concentrations close to ambient background levels, as long as the device is routinely calibrated with an accurate reference instrument. Having a widely deployed network of such low-cost CH4 sensors would allow improved identification, monitoring and mitigation of a variety of CH4 emissions.