Apparatus and methods for location and sizing of trace gas sources
Inventors
Rieker, Gregory B. • Prasad, Kuldeep • Alden, Caroline B. • Coburn, Sean C. • Wright, Robert J.
Assignees
University of Colorado Denver • United States Department of Commerce
Publication Number
US-10690562-B2
Publication Date
2020-06-23
Expiration Date
2037-10-18
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Abstract
A system for detecting gas leaks and determining their location and size. A data gathering portion of the system utilizes a chosen geometrical configuration to collect path-integrated spectroscopic data over multiple paths around an area. A processing portion of the system applies a transport model together with meteorological data of the area to generate an influence function of possible leak locations on gas detector measurement paths, and applies an inversion model to the influence function, prior data, and the spectroscopic data to generate gas source size and location.
Core Innovation
The invention provides apparatus and methods for detecting and geographically characterizing gas leaks, including determining their size and location. The system utilizes a spectrometer gas detector to collect path-integrated spectroscopic data over multiple open paths around a geographical area. It combines this spectroscopic data with meteorological data related to the area and employs a transport model to generate source-receptor relationships that indicate how emissions from potential leak locations influence measurements along detector paths. An inversion model is then applied to these relationships, prior data on known or potential gas sources, and the spectroscopic data to produce information on gas source size and location.
The invention addresses the problem in existing gas leak detection methods where current open-path measurement techniques suffer from significant limitations such as high measurement uncertainty, interference from overlapping absorption features, the need for frequent calibration, operator involvement, and difficulty in simultaneously measuring conditions like water vapor, temperature, and pressure. Previous techniques lack precision for detecting methane leaks over kilometer-scale distances without excessive expense or operational complexity. Furthermore, there is a need to account for background emissions and to improve the geographical characterization of leaks.
The invention overcomes these limitations by using dual comb spectroscopy (DCS) which enables broadband, simultaneous, and interference-free measurement of multiple gas species and atmospheric conditions without requiring calibration or operator intervention. The system employs configurable data gathering geometries such as fenceline, orthogonal beam sampling, or clustering configurations involving retroreflectors or mobile reflectors. It incorporates robust transport models coupled with prior data, including uncertainty, in sophisticated inversion processing to isolate leak signals from background levels and accurately estimate location and emission strength. Additionally, the method uses statistical techniques such as bootstrapping to quantify uncertainty and reduce false positives.
Claims Coverage
The patent includes two independent claims outlining methods and apparatus for characterizing gas sources in a geographical area using a combination of spectrometer measurements, transport modeling, inversion techniques, and prior data.
Using transport model with meteorological data to create source-receptor relationships
Employing a transport model coupled with meteorological data to generate relationships describing the influence of emissions from potential gas sources on path-integrated spectroscopic data collected over open paths around the area.
Applying inversion model with prior data and spectroscopic measurements
Determining emissions information such as presence, location, and size of gas sources by applying an inversion model to source-receptor relationships, path-integrated spectroscopic data, and prior data indicating known or potential gas sources.
Collecting path-integrated spectroscopic data using a spectrometer and retroreflectors
Using a spectrometer unit transmitting light to multiple retroreflectors arranged over the area and detecting reflected light to generate path-integrated spectroscopic data along open paths between the spectrometer and each retroreflector.
Incorporating background isolation and uncertainty in inversion processing
Isolating source signals from background in the spectroscopic data to obtain observation data and applying the inversion model to this observation data, prior data, source-receptor relationships, and uncertainties related to data interpretation.
Employing various transport and inversion modeling techniques
Utilizing transport models such as large eddy simulation, Lagrangian particle dispersion, or Gaussian plume models, and inversion techniques including least-squares fitting or Bayesian inversion to estimate emissions.
Using different data gathering geometries
Implementing configurations such as fenceline where retroreflectors surround the area, orthogonal beam sampling with upwind and downwind reflectors, and clustering multiple spectrometer units jointly analyzing data to improve detection and characterization.
Bootstrapping model uncertainties for emission likelihood assessment
Applying bootstrapping statistical methods to model uncertainties to produce empirical distributions of source strength at potential source locations, aiding in determining the likelihood of non-zero emission rates and reducing false positives.
The claims collectively cover a comprehensive system and method for gas leak detection and characterization that integrates advanced spectroscopic measurements, atmospheric transport modeling, statistical inversion, and prior knowledge within flexible data gathering geometries to accurately locate and size trace gas sources while accounting for background variations and uncertainties.
Stated Advantages
Provides improved detection and geographical characterization of gas leaks including accurate size and location determination.
Uses dual comb spectroscopy enabling interference-free, calibration-free, and drift-free measurements with simultaneous multi-species and atmospheric condition detection.
Eliminates need for operator involvement and enables interrogation of multiple locations simultaneously.
Employs configurable data gathering geometries allowing flexibility in monitoring various site layouts and conditions.
Incorporates prior data and uncertainty into inversion processing, improving reliability and reducing false positives.
Enables detection of small leaks over long open paths with high sensitivity and accuracy.
Documented Applications
Detecting, locating, and sizing methane leaks at oil and gas facilities over kilometer-scale distances.
Monitoring emissions from industrial sites, agricultural sites, animal-raising operations, or chemical and biological weapons releases.
Detecting chemical leaks in industrial facilities other than methane.
Monitoring CO2 leaks at carbon sequestration sites.
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