Supercritical Flow Measurement Error Correction
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Solution Overview
Problem
Coriolis flow sensors face significant challenges in accurately measuring mass flowrates of supercritical fluids like ethylene due to large changes in density and speed of sound with pressure and temperature, leading to high error rates that exceed acceptable limits.
Innovation Solution
A computer-based system infers the speed of sound of the flow fluid using an inferential relationship between measured density and inferred speed, accounting for pressure and heat capacity ratio, to correct mass flowrate measurements and reduce errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If Coriolis flow sensors are used to measure mass flowrate of supercritical fluids, then flow measurement capability is provided, but measurement precision deteriorates due to large density and speed of sound changes with pressure and temperature
Solution Approach 1:
The patent applies parameter changes by using multiple sensors (vibratory density sensor, temperature sensor, pressure sensor) to detect changes in fluid parameters (density, temperature, pressure) and using these measured parameters to dynamically correct the mass flowrate measurement through computational processing, thereby compensating for the deteriorating measurement precision caused by supercritical fluid parameter variations
Solution Approach 2:
The patent implements feedback by using the measured density, temperature, and pressure values to continuously adjust and correct the mass flowrate determination. The system feeds back the sensed parameter information to the processing unit, which applies correction algorithms to improve measurement accuracy in real-time based on the actual fluid state
2Productivity
If larger Coriolis flow sensors operate at higher frequencies, then flow measurement range is increased, but speed of sound effects cause higher measurement errors
Solution Approach 1:
The patent uses parameter changes by measuring the actual speed of sound through vibratory density sensor measurements and using this measured parameter to correct the mass flowrate calculation. This dynamic parameter adjustment compensates for the speed of sound effects that increase with sensor size and operating frequency, allowing larger sensors to maintain accuracy across extended measurement ranges
3Adaptability or versatility
If pressure varies by 100 psi in typical pipelines, then operational flexibility is maintained, but speed of sound effects propagate to cause up to 3% error in flow measurements
Solution Approach 1:
The patent implements feedback by continuously measuring pressure with a pressure sensor and using this feedback information to correct the mass flowrate measurement. The system responds to pressure variations by adjusting the measurement calculation based on the measured pressure value and its effect on speed of sound, thereby maintaining measurement precision despite the operational flexibility that allows 100 psi pressure variations
Solution Approach 2:
The patent applies parameter changes by using the measured pressure parameter to dynamically adjust the mass flowrate calculation. As pressure changes occur during operation, the system updates the speed of sound value based on the new pressure measurement and相应ly adjusts the correction factor, maintaining accuracy across the full operational pressure range
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 method effectively reduces mass flowrate measurement errors caused by speed of sound effects, improving accuracy and meeting the requirement of less than 0.5% error in flow measurements.
Implementation Method 1
measuring a measured density with a density sensor
Implementation Method 2
speed of sound (hereinafter, 'SoS') of ethylene (and other substances) also varies significantly with changes in pressure and/or temperature
Implementation Method 3
Coriolis flow sensors are typically preferred for this reason
Data Source
AI summary
A method for inferring an inferred speed of sound of a flow fluid is disclosed. The method is conducted by a computer system (200) having a processor (210) and a memory (220), the processor (210) configured to execute instructions from the memory (220) and store data in the memory (220), the memory (220) having a SoS inference module (202). The method includes inferring, by the SoS inference module (202), the inferred speed of sound of the flow fluid based on an inferential relationship between a measured density of the flow fluid and the inferred speed of sound of the flow fluid.