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CN-114599941-B - Enhanced supercritical fluid measurement with vibration sensor

CN114599941BCN 114599941 BCN114599941 BCN 114599941BCN-114599941-B

Abstract

A method for deriving a derived sound velocity of a flowing fluid is disclosed. The method is performed by a computer system (200) having a processor (210) and a memory (220), the processor (210) being configured to execute instructions from the memory (220) and store data in the memory (220), the memory (220) having a SoS derivation module (202). The method includes deriving, by a SoS derivation module (202), a derived sound velocity of the flowing fluid based on a derived relationship between a measured density of the flowing fluid and the derived sound velocity of the flowing fluid.

Inventors

  • ANDREW TIMOTHY PATTEN
  • Antony William pancratz

Assignees

  • 高准有限公司

Dates

Publication Date
20260508
Application Date
20191101

Claims (20)

  1. 1. A method for deriving sound speed of a flowing fluid in a supercritical state in a vibrating flow sensor, the method being performed 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 derivation module (202), the method comprising: Measuring the density of the flowing fluid by an external density sensor (10), wherein the external density sensor is not affected by SoS effects of the flowing fluid and has at least one of 1) a smaller diameter compared to the vibrating flow sensor, 2) a lower vibration frequency compared to the vibrating flow sensor, and 3) a predetermined distance threshold relative to the vibrating flow sensor, wherein SoS effects comprise undesired changes in measured SoS due to pressure and/or temperature; -deriving, by the SoS derivation module (202), the derived sound velocity of the flowing fluid in real time based on a derived relationship between a measured density and heat capacity ratio of the flowing fluid and the derived sound velocity of the flowing fluid.
  2. 2. The method of claim 1, wherein the derived relationship between the derived sound speed of the flowing fluid and the density of the flowing fluid is an inverse relationship between the derived sound speed of the flowing fluid and a square root of the measured density of the flowing fluid.
  3. 3. The method of claim 2, wherein the derived relationship between the derived sound speed of the flowing fluid and the density of the flowing fluid also takes into account the pressure of the flowing fluid, wherein the pressure of the flowing fluid is one or more of a measured pressure measured by a pressure sensor (20) and a pressure derived from a density sensor (10) stiffness determination.
  4. 4. The method of claim 3, wherein the derived relationship is based on a relationship between the derived sound velocity of the flowing fluid and a square root term that divides the square root of the product of the heat capacity ratio and the pressure by the square root of the measured density.
  5. 5. The method of claim 4, wherein the heat capacity ratio is associated with one or more of the flowing fluid and a set of flowing fluids of which the flowing fluid is a constituent, and wherein the heat capacity ratio is one or more of temperature-dependent and pressure-dependent such that the heat capacity ratio is determined based on a corresponding predetermined relationship between the heat capacity ratio and one or more of measured temperature and pressure.
  6. 6. The method of one of claims 1 to 5, wherein the computer system (200) is a density sensor meter electronics (120) of the density sensor (10), the method further comprising transmitting the derived sound speed of the fluid by the density sensor (10) to a vibration sensor (5).
  7. 7. The method of claim 6, further comprising deriving, by the density sensor meter electronics (120), a derived flow fluid pressure based on a measured stiffness of an element of the density sensor (10) determined by the density sensor (10) if the derived relationship between the measured density of the flow fluid and the derived sound speed of the flow fluid takes into account flow fluid pressure.
  8. 8. The method of one of claims 3 to 5, wherein the computer system (200) is a vibrating flow sensor meter electronics (110) of a vibrating flow sensor (5), the method further comprising: -receiving, by the computer system (200), the measured density from a density sensor (10); receiving, by the computer system (200), the pressure of the flowing fluid, and A corrected mass flow rate is determined by the computer system (200) based on the derived sound speed of the flowing fluid.
  9. 9. The method according to claim 6, wherein the vibration sensor (5) has one or more of the following characteristics: Vibrating the vibrating element of the vibration sensor (5) at a frequency greater than or equal to 300 Hz, and Having an inner diameter greater than or equal to two inches, and wherein the density sensor (10) has one or more of the following characteristics: vibrating a vibrating element of the density sensor (10) at a frequency of less than 300 Hz, and Having an inner diameter of less than two inches.
  10. 10. The method of claim 1, wherein the flowing fluid comprises one or more of ethylene, ethane, carbon dioxide, and argon.
  11. 11. An apparatus for deriving sound speed, soS, of a flowing fluid in a supercritical state in a vibrating flow sensor, the apparatus having a computer system (200), the 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 derivation module (202), the computer system (200) configured to: Measuring the density of the flowing fluid by an external density sensor (10), wherein the external density sensor is not affected by SoS effects of the flowing fluid and has at least one of 1) a smaller diameter compared to the vibrating flow sensor, 2) a lower vibration frequency compared to the vibrating flow sensor, and 3) a predetermined distance threshold relative to the vibrating flow sensor, wherein SoS effects comprise undesired changes in measured SoS due to pressure and/or temperature; -deriving, by the SoS derivation module (202), the derived sound velocity of the flowing fluid in real time based on a derived relationship between a measured density and heat capacity ratio of the flowing fluid and the derived sound velocity of the flowing fluid.
  12. 12. The apparatus of claim 11, wherein the derived relationship between the derived sound speed of the flowing fluid and the density of the flowing fluid is an inverse relationship between the derived sound speed of the flowing fluid and a square root of the measured density of the flowing fluid.
  13. 13. The apparatus of claim 12, wherein the derived relationship between the derived sound velocity of the flowing fluid and the density of the flowing fluid also takes into account the pressure of the flowing fluid, wherein the pressure of the flowing fluid is one or more of a measured pressure measured by a pressure sensor (20) and a pressure derived from a density sensor (10) stiffness determination.
  14. 14. The apparatus of claim 13, wherein the derived relationship is based on a relationship between the derived sound velocity of the flowing fluid and a square root term that divides a square root of a product of the heat capacity ratio and pressure by a square root of the measured density.
  15. 15. The apparatus of claim 14, wherein a heat capacity ratio is associated with one or more of the flowing fluid and a set of flowing fluids that form part of the flowing fluid, and wherein the heat capacity ratio is one or more of temperature-dependent and pressure-dependent such that the heat capacity ratio is determined based on a corresponding predetermined relationship between the heat capacity ratio and one or more of measured temperature and pressure.
  16. 16. The apparatus of one of claims 11 to 15, wherein the computer system (200) is a density sensor meter electronics (120) of the density sensor (10), the density sensor (10) being configured to transmit the derived sound speed of the fluid to a vibration sensor (5).
  17. 17. The apparatus of claim 16, wherein if the derived relationship between the measured density of the flowing fluid and the derived sound velocity of the flowing fluid takes into account a flowing fluid pressure, the density sensor meter electronics (120) is configured to derive a derived flowing fluid pressure based on a measured stiffness of an element of the density sensor (10) determined by the density sensor (10).
  18. 18. The apparatus of one of claims 13 to 15, wherein the apparatus is a vibratory flow sensor (5), the computer system (200) is a vibratory flow sensor meter electronics (110) of the vibratory flow sensor (5), the computer system (200) further configured to: -receiving the measured density from the density sensor (10); receiving the pressure of the flowing fluid, and A corrected mass flow rate is determined based on the derived sound speed of the flowing fluid.
  19. 19. The device according to claim 16, wherein the vibration sensor (5) has one or more of the following characteristics: Vibrating the vibrating element of the vibration sensor (5) at a frequency greater than or equal to 300 Hz, and Having an inner diameter greater than or equal to two inches, and wherein the density sensor (10) has one or more of the following characteristics: vibrating a vibrating element of the density sensor (10) at a frequency of less than 300 Hz, and Having an inner diameter of less than two inches.
  20. 20. The apparatus of one of claims 11 to 15, wherein the flowing fluid comprises one or more of ethylene, ethane, carbon dioxide, and argon.

Description

Enhanced supercritical fluid measurement with vibration sensor Technical Field Embodiments described below relate to mass flow sensors, and more particularly, to calibrating mass flow sensors. Background Some materials are optimally transferred at high temperature and/or high pressure in critical and/or supercritical phase conditions (hereinafter referred to as "supercritical"). An exemplary material is ethylene. For example, when ethylene is used as a feedstock for a plastic manufacturing process, ethylene is often pumped at high pressure in critical phase conditions. The density of the supercritical phase ethylene is higher than gaseous ethylene and therefore its pumping cost is generally relatively low. The flow measurement determination of ethylene is typically a mass flow rate determination. Supercritical phase ethylene is particularly non-ideal, meaning that its density and sonic properties vary significantly with small changes in temperature and/or pressure. This makes flow measurement very difficult for all technologies, including coriolis flow sensors. The supercritical phase ethylene is typically transferred at a pressure of 50 bar or more. The temperature is typically about ambient temperature, possibly about 20 ℃, but since the pipeline is typically located underground, the temperature may vary depending on the geological conditions. In the supercritical range, the density of ethylene (and other substances) varies significantly with pressure and/or temperature. For example, a pressure change of 1 pound force per square inch (hereinafter "psi") may result in a density change of 2 kilograms per cubic meter (hereinafter "kg/m 3"). The ideal gas exhibits significantly less pronounced changes, for example, a density change of less than 0.1kg/m 3 for a pressure change of 1 psi. For this reason, coriolis flow sensors are generally preferred. Small changes in pressure and/or temperature result in large density changes, which makes it challenging to determine mass flow rate using a combination of a density sensor and a volumetric flow sensor. In addition to the change in density, the speed of sound (hereinafter, referred to as "SoS") of ethylene (and other substances) also significantly changes with changes in pressure and/or temperature. For example, a pressure change of 1psi may result in a SoS change of 5 meters per second (hereinafter, referred to as "m/s"), where the SoS of the ideal gas does not change with pressure. Some coriolis flow sensors, such as larger coriolis flow sensors, are susceptible to SoS effects. Some larger coriolis flow sensors have such high errors that they are not meaningful for use in applications where the fluid is in a critical state. Error propagation from the sound velocity effect is more pronounced in sensors with larger flow tube inner diameters and sensors operating at higher frequencies. When the speed of sound of the flowing fluid is low, the speed of sound error in the mass flow rate determination is high. For example, a 1psi change that may result in a 5m/s SoS change may also result in a 0.03% change in coriolis flow sensor measurements. The pressure in a typical line may vary by 100psi, which may result in a 3% error in the flow measurement provided by the coriolis sensor. A typical requirement of the measurement results is that there is less than 0.5% error. Many specifications dictate that the error should be less than 0.35%. Mass flow rate equations and relationships that take into account the speed of sound may correct the mass flow rate for the speed of sound effect. There are many equations and relationships in the prior art to correct for mass flow rate using the speed of sound of a flowing fluid. An example can be found in U.S. patent number 6,412,355B1. The mass flow rate correction method of this patent is contemplated by this specification and incorporated herein by reference, but it should be understood that these are merely exemplary and that other embodiments of mass flow rate correction algorithms that take into account the speed of sound exist and may be used with the features of the present disclosure. These equations and relationships may make larger coriolis flow sensors useful in more applications where the sound velocity effect is significant. Accordingly, a method for correcting the effects of sound velocity in coriolis flow sensors is needed. Disclosure of Invention Embodiments of a method for deriving sound velocity of a flowing fluid are disclosed. The method is performed by a computer system (200) having a processor (210) and a memory (220), the processor (210) being configured to execute instructions from the memory (220) and store data in the memory (220), the memory (220) having a SoS derivation module (202). The method includes deriving, by a SoS derivation module (202), a derived sound velocity of the flowing fluid based on a derived relationship between a measured density of the flowing fluid and the derived sound velocity of the f