Identifying sources of fugitive emissions in industrial facilities using trajectory statistical methods

Remote ambient methane monitoring using fiber-optically coupled optical sensors

“…) values are lower than published results from comparable fiber-coupled 2f-WMS systems implementing all-optical remote sensors [19,21] and meet the suggested requirements for the reliable measurement of transient fugitive methane plumes [9].…”

“…The achieved LDL of 1.56 ppm v (or an instrument-dependent absorbance of 6.32 × 10 −7 cm −1 ) is lower than the targeted LDL of ~1.7 ppm v (or ~6.9 × 10 −7 cm −1 ) for remote detection of ambient methane. In addition, the obtained measurement precision of 1.36 ppm v (or 5.51 × 10 −7 cm −1 ) is comparable to the suggested minimum precision of 2.0 ppm v (or 8.10 × 10 −7 cm −1 ) required to locate fugitive methane sources using statistical trajectory methods [9].…”

“…Given that the latter activities would most likely occur during field maintenance and there is also potential for fiber breakage and replacement in an industrial setting, the ambient methane concentration (zero response) would need to be established regularly to minimize the accumulation of bias errors. Simulation suggests [9] that an ambient methane concentration estimation should be achievable by way of software analysis, due to the infrequent interaction of fugitive emission plumes with sensors in a distributed network.…”

“…Moreover, current methods for detection of fugitive emissions, which most often involve using survey teams equipped with handheld vapor analyzers [7] or infrared cameras [8], are generally labor-intensive and necessarily intermittent. Recent work on trajectory and inverse methods for interpreting sensor network data to locate and quantify unknown fugitive sources suggests that a measurement standard deviation of 2 ppm v (equivalent to an absorbance of 8.1 × 10 −7 cm −1 for the 2v 3 R(3) methane manifold at standard atmospheric pressure and temperatures) is sufficient to locate and potentially quantify fugitive methane sources using statistical methods [9], and possibly as high as 29 ppm v using adjoint-based inverse dispersion modeling [10]. This paper reports development and quantitative testing of a fiber-coupled, optically networked detection system designed for measuring in situ ambient methane concentrations within an industrial environment, such as an oil and gas processing plant.…”

“…The simplicity, selectivity, and theoretically achievable precision of the 2f-WMS technique show promise for remote monitoring of ambient methane, but will require specific attention to system design to achieve a measurement precision and lower detection limit required for detecting and monitoring fugitive methane plumes [9], less than 8.1 × 10 −7 and 6.9 × 10 −7 cm −1 , respectively. In the present work, a purpose-built TDLAS system with the ability to optically monitor ambient methane over multiple multiplexed sensors via a telecommunications-grade single-mode (SM) fiber-optical network is presented.…”