Optical Flow Cell Assembly for High-Velocity Flare Gas Metering
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Solution Overview
Problem
Conventional gas flow metering systems for flare gas in hydrocarbon drilling and production rigs face challenges in accuracy, reliability, and adaptability to extreme conditions, including high flow velocities, varying gas compositions, and contamination, which affect their ability to measure flow rates effectively.
Innovation Solution
A flow cell assembly with an optical probe and sensor array that measures gas velocity and physical properties, capable of withstanding high pressures and temperatures, and providing data for emissions monitoring and formation evaluation, adaptable to existing flare pipes and drilling operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional turbine meters are used to measure gas flow rate, then the measurement can be performed with a simple mechanical structure, but the system cannot withstand high flow velocities in excess of 100 m/s and the rotor components are subject to wear by contaminants
Solution Approach 1:
The patent replaces the mechanical turbine rotor system with an optical measurement system using laser beams and light scattering detection. This eliminates mechanical wear from bearings and rotor blades while enabling measurement of high velocities exceeding 100 m/s through non-contact optical particle tracking
Solution Approach 2:
The patent introduces gas particles as an intermediary medium to carry information about flow velocity. By tracking the movement of naturally occurring particles through laser light scattering, the system indirectly measures gas flow without direct mechanical contact, avoiding wear while maintaining measurement capability
2Speed
If thermal mass meters are used to measure gas flow rate, then the measurement principle is simple based on temperature difference, but the flow range is limited to 0.3 to 30 m/s which excludes high velocity applications
Solution Approach 1:
The patent replaces thermal mass measurement with optical particle tracking. Instead of measuring temperature differences caused by heat transfer, the system uses laser light scattering to directly track particle velocity, enabling accurate measurement of high velocities up to and exceeding 100 m/s while maintaining measurement precision through optical detection
3Measurement precision
If ultrasonic flow meters are used to measure gas flow rate, then the time-of-flight measurement principle provides good accuracy, but the system requires pockets in pipe walls for sensor containment and long sections of pipe which increase system complexity
Solution Approach 1:
The patent extracts the measurement function from complex pipe-mounted ultrasonic sensors and pipe wall pockets, concentrating it into a compact optical probe that can be inserted into the flow. This eliminates the need for pipe modifications and long measurement sections while maintaining measurement precision through direct optical particle tracking in the flow stream
4Speed
If optical flow meters measuring particle velocity are used, then high flow velocities can be measured without mechanical wear, but the system requires laser sources, optical lenses, and multiple windows in pipe walls which increase device complexity
Solution Approach 1:
The patent merges the optical measurement functions into a single integrated flow cell assembly that combines the flow cell, optical probe with laser source and lenses, mounting assembly, and particle introduction system. This consolidation reduces the number of separate components and simplifies installation while maintaining the capability to measure high velocities without mechanical wear
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
The system provides accurate and reliable flow rate measurements, enabling effective emissions monitoring, carbon footprint analysis, and formation evaluation, while being robust and cost-efficient for use in harsh drilling environments.
Implementation Method 1
The particles entrained in the gas flow that travel along a trajectory coincident with the two focal points, scatter the light in succession and the time delay between scatter occurrences is inversely proportional to the particle velocity
Implementation Method 2
The transmission time of the signal is measured at increments along a diagonal path in both a downstream and upstream direction
Data Source
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AI summary
A flow cell assembly for measuring the flow rate of gas in a pipe having an optical probe mounted on a flow cell inserted between sections of pipe. A distal end of the optical probe is disposed within an internal bore of the flow cell. The optical probe is capable of measuring the velocity of particles in a gas flowing through the internal bore. A sensor mechanism may be mounted on the flow cell and have a sensor array with a distal end disposed within the flow cell internal bore. The sensor array is capable of measuring physical properties of the gas. The optical probe is self-aligned when mounted to the flow cell through the use of a locking cam and an orientation ring. Velocity and physical property measurements are used to calculate flow rate. Alternatively, the optical probe and sensor mechanism may be mounted directly onto an existing pipe.