Void Fraction Calibration via Microwave Resonator and Coriolis Meter
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Solution Overview
Problem
Current methods for calculating the mass flow rate of multiphase flows, particularly in hydrocarbon extraction, face challenges due to phase contamination and the need for expensive, maintenance-intensive separators and hazardous radiometric densitometers, which result in inaccurate measurements and safety concerns.
Innovation Solution
A method and apparatus using a Coriolis meter and microwave meter, calibrated with a radiometric densitometer, to calculate the mass flow rate by deriving phase volume fractions and correcting apparent measurements with error curves, allowing for accurate determination of mass flow rates without the need for permanent radiometric densitometers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If radiometric densitometers are used to measure bulk density accurately, then measurement precision is improved, but device complexity and safety hazards increase due to required shielding and hazardous radioactive sources
Solution Approach 1:
The patent introduces a microwave resonator as an intermediary device that measures bulk permittivity instead of directly measuring bulk density with radiometric equipment. The microwave resonator couples to both liquid and gas phases to provide an indirect measurement that avoids the need for hazardous radioactive sources while still enabling accurate phase fraction determination through calibration
Solution Approach 2:
The patent replaces the radiometric measurement system (which uses electromagnetic radiation from radioactive sources) with a microwave-based resonant system. This substitution eliminates the need for hazardous radioactive materials and extensive shielding while maintaining measurement capability through a different physical principle (microwave resonance rather than gamma/x-ray attenuation)
2Device complexity
If Coriolis meters are used to measure mass flow rate and bulk density, then device complexity is reduced compared to radiometric methods, but measurement precision deteriorates due to phase contamination and poor coupling between dispersed and continuous phases
Solution Approach 1:
The patent combines measurements from multiple devices (Coriolis meter for apparent bulk density and mass flow rate, microwave resonator for bulk permittivity) to compensate for the weaknesses of each individual device. By merging these measurement streams and using calibration data, the system achieves accurate phase fraction and mass flow rate determination that overcomes the phase contamination limitations of the Coriolis meter alone
Solution Approach 2:
The patent implements a calibration and correction process where measurement data from the Coriolis meter and microwave resonator are fed into a computational system that applies calibration factors and error corrections. This feedback mechanism allows the system to compensate for phase contamination effects and improve measurement precision through iterative correction based on known flow conditions
3Measurement precision
If separators are used to separate phases before measurement, then measurement precision is improved by eliminating phase mixing, but device complexity and maintenance requirements increase significantly
Solution Approach 1:
The patent extracts the measurement function from the separation function, eliminating the need for physical separators. Instead of separating phases mechanically and then measuring them, the system uses microwave resonator and Coriolis meter measurements taken directly on the multiphase flow, combined with calibration data, to determine phase fractions without requiring phase separation infrastructure
Solution Approach 2:
The patent makes the measurement system universal by designing it to handle multiphase flows directly without requiring separate measurement lines for each phase. The microwave resonator and Coriolis meter can measure properties of the mixed multiphase flow, and through calibration and computational analysis, extract phase-specific information, eliminating the need for multiple dedicated measurement systems
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 and safe measurement of mass flow rates in multiphase flows, reducing errors and operational costs by using non-invasive and less bulky equipment, with the ability to monitor and verify calibration for ongoing accuracy.
Implementation Method 1
Coriolis meters comprise tubes that are vibrated at their natural frequency. When no flow is present, the tubes vibrate in phase and show no sign of twist. Once a flow is introduced, Coriolis forces give rise to a twisting effect in the tubes.
Implementation Method 2
Such meters comprise tubes that are vibrated at their natural frequency
Implementation Method 3
One such method involves using a device which is sensitive to changes in the permittivity of the flow, such as a microwave resonator
Implementation Method 4
such as a microwave resonator
Implementation Method 5
Radiometric densitometers, such as gamma and x-ray densitometers
Implementation Method 6
Radiometric densitometers, such as gamma and x-ray densitometers
Data Source
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AI summary
According to the invention, a method is provided of producing a void fraction (VF) error curve which correlates an apparent VF with the actual VF of a multi-phase flow, the method comprising: a) Using a device to measure a property of the multi-phase flow from which an apparent VF may be calculated; b) Calculating the apparent VF using the measured property from the device; c) Determining the actual VF of the multiphase flow using a radiometric densitometer; d) Using the values from b) and c) to calculate the VF error; e) Repeating b) - d) for all expected flow conditions to generate a VF error curve.