Optical Gas Detection for Methane Emission Characterization
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Solution Overview
Problem
Existing methods for detecting methane emissions, such as optical gas imaging and Method 21, are limited by weather conditions and require extensive infrastructure, and there is a need for more effective technologies to reduce fugitive methane emissions from natural gas infrastructure and other sources.
Innovation Solution
The use of optical gas detectors that employ optical beams to measure path-integrated absorption measurements, combined with retroreflected beams and multiple spectrometers, to characterize emissions by determining gas concentrations, sources, and plume parameters, allowing for real-time adaptive sampling and background concentration estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical gas imaging (OGI) is used to detect methane emissions, then detection capability is improved, but the system becomes sensitive to weather conditions and background emissivities
Solution Approach 1:
The patent replaces infrared thermal imaging (mechanical/optical system sensitive to weather) with direct absorption spectroscopy using optical beams at specific wavelengths. This substitution eliminates sensitivity to background emissivities and weather conditions by directly measuring molecular absorption rather than thermal radiation patterns.
Solution Approach 2:
The patent changes the detection parameter from broadband infrared radiation detection to narrowband absorption measurement at specific molecular resonant frequencies. By tuning optical beams to match methane's absorption lines, the system achieves selective detection that is independent of background thermal conditions and weather variations.
2Measurement precision
If traditional OGI or Method 21 is used for emission surveys, then methane detection is achieved, but extensive infrastructure and equipment are required
Solution Approach 1:
The patent extracts the core detection function from complex infrastructure systems (infrared cameras, portable analyzers, support equipment) and implements it using simplified optical beam transmission and absorption measurement. This extraction eliminates the need for extensive infrastructure while maintaining detection capability.
Solution Approach 2:
The patent employs cost-effective optical components and methods that do not require expensive, maintenance-intensive infrastructure. The system uses simple optical beams and absorption measurements rather than costly infrared imaging systems or complex portable analytical equipment.
3Measurement precision
If path-integrated absorption measurements are used, then detection accuracy is improved, but the system requires multiple optical beams and spectrometers
Solution Approach 1:
The patent segments the detection task into multiple optical beams traveling along different paths, with each beam providing independent absorption measurements. This segmentation enables path-integrated measurements that improve accuracy by sampling different spatial regions and combining the data.
Solution Approach 2:
The patent makes the optical beam system multi-functional by using the same basic optical components for multiple measurement paths and purposes. The system can simultaneously perform emission detection, background characterization, and spatial mapping using unified optical instrumentation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach provides accurate, cost-effective, and efficient detection and characterization of methane emissions by reducing the need for extensive infrastructure and improving detection accuracy under varying weather conditions.
Implementation Method 1
optical gas detectors that employ optical beams to measure path-integrated absorption measurements
Implementation Method 2
combined with retroreflected beams and multiple spectrometers
Data Source
AI summary
A method characterizes gas emissions inside an area bounded by first, second, third, and fourth paths. A first spectrometer transmits a first beam along the first path. The first beam is retroreflected back to the first spectrometer, where it is detected to obtain a first signal. A second spectrometer transmits a second beam along the second path. The second beam is retroreflected back to the second spectrometer, where it is detected to obtain a second signal. A third spectrometer transmits a third beam along the third path. The third beam is retroreflected back to the third spectrometer, where it is detected to obtain a third signal. A fourth spectrometer transmits a fourth beam along the fourth path. The fourth beam is retroreflected back to the fourth spectrometer, where it is detected to obtain a fourth signal. The four signals are processed to identify gas sources inside the area.