Backscatter-TDLAS Detectors for Monitoring, Locating, Imaging, and Quantifying Methane Emissions

Frish, Michael B.; Chen, Shin-Juh; Aubut, Nicholas F.; Wainner, Richard T.; Wehnert, P.; Bendele, Kevin; Chancey, Steve

doi:10.1364/cleo_at.2022.jw3a.16

Cited by 1 publication

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“…The Discover AMLD system integrates b-TDLAS with mid-infrared laser sources that enable parts per billion detection in the Discover 1 m backscatter path length. [7] Ethane is typically found in natural gas at percent-level and is the second gas species measured. The knowledge of ethane concentration helps in attributing the source of the detected methane.…”

Section: Technology Approachmentioning

confidence: 99%

Versatile advanced mobile natural gas leak detection system

Chen

Aubut

Frish

et al. 2023

Next-Generation Spectroscopic Technologies XV

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The need to rapidly detect, locate and repair natural gas leaks from natural gas infrastructure has become ever more urgent since methane is recognized as a potent greenhouse gas and is contributing to the global climate change. An optical gas sensor based on mid-infrared lasers and the method of backscattering tunable diode laser absorption spectroscopy is developed and provides gas concentration measurements with parts per billion by volume sensitivity. Ethane is a secondary component of natural gas. Concurrent methane and ethane measurement discriminates natural gas from biogas. The ability to approximate emission rate and leak location helps to prioritize repairs. This dual-gas optical gas sensor weighs about 2 kg, is battery-powered and is designed to be easily installed and removed from survey vehicles. A scattering target placed 1-m away from the gas sensor unit provides an open-path configuration for the laser beams to analyze ambient air. While the vehicle is traveling at 10 m/s, this gas sensor package is sensitive to cm-scale gas plumes due to a sample frequency of 100 Hz with data output rate at 10 Hz. Gas concentrations, GPS, and wind information along the survey route are collected wirelessly and processed with a computing tablet. Cloud-based data analytics further process the survey data. Early blind survey testing covered 54 natural gas leaks and 7 sewer emissions. Nearly 100% find rate for all true natural gas leaks was achieved with very low false positives and negatives. Leak indications were verified with follow-up survey with boots on the ground.

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Section: Technology Approachmentioning

confidence: 99%