Wet gas measurement

• US 8,126,661 B2
• Filed: 11/06/2009
• Issued: 02/28/2012
• Est. Priority Date: 08/28/2006
• Status: Active Grant

• Current Assignee: Schneider Electric Systems USA, Inc. (Schneider Electric SE)
• Original Assignee: Invensys Systems Incorporated (Invensys PLC)
• Inventors: Henry, Manus P., Tombs, Michael S.
• Primary Examiner(s): Charioui, Mohamed
• Assistant Examiner(s): Desta, Elias
• Application Number:
  US12/614,156
• Publication Number:
  US 20100211346A1
• Time in Patent Office: 844 Days
• Field of Search: 738/613.56, 738/613.57, 738/613.55, 738/615.2, 738/615.3, 702/12, 702/45, 702/48, 702/100
• US Class Current: 702/48
• CPC Class Codes: G01F 1/74 Devices for measuring flow of a fluid or flow of a fluent solid material in suspension in another fluid
• CPC Class Codes: G01F 1/8409 constructional details
• CPC Class Codes: G01F 1/8431 electronic circuits
• CPC Class Codes: G01F 1/8436 signal processing
• CPC Class Codes: G01F 1/8481 having loop-shaped measuring conduits, e.g. the measuring conduits form a loop with a crossing point
• CPC Class Codes: G01F 1/8486 with multiple measuring conduits
• CPC Class Codes: G01F 15/024 involving digital counting
• CPC Class Codes: G01F 25/10 of flowmeters
• CPC Class Codes: G01N 9/002 using variation of the resonant frequency of an element vibrating in contact with the material submitted to analysis G01N9/34 takes precedence

Abstract

A multi-phase process fluid is passed through a vibratable flowtube. Motion is induced in the vibratable flowtube. A first apparent property of the multi-phase process fluid based on the motion of the vibratable flowtube is determined, and an apparent intermediate value associated with the multi-phase process fluid based on the first apparent property is determined. A corrected intermediate value is determined based on a mapping between the intermediate value and the corrected intermediate value. A phase-specific property of a phase of the multi-phase process fluid is determined based on the corrected intermediate value.

Claims

1. A method comprising:

passing a multi-phase process fluid through a vibratable flowtube, the multi-phase process fluid comprising more gas than liquid during a first period and more liquid than gas during a second period;

inducing motion in the vibratable flowtube;

determining a first apparent property and a second apparent property of the multi-phase process fluid based on the motion of the vibratable flowtube, the first apparent property being associated with the multi-phase process fluid during the first period, the second apparent property being associated with the multi-phase fluid during the second period, and the first and second apparent properties incorporating respective inaccuracies caused by the multi-phase process fluid passing through the flowmeter;

determining a first apparent intermediate value based on the first apparent property and a second apparent intermediate value based on the second apparent property;

determining a first modified intermediate value based on the first apparent intermediate value and a second modified intermediate value based on the second apparent intermediate value, the first and second modified intermediate values at least partially correcting for the inaccuracy caused by the multi-phase process fluid passing through the flowmeter;

determining, based on the first modified intermediate value, a phase-specific property of a phase of the multi-phase process fluid passing through the flowtube during the first period; and

determining, using one or more processing devices and based on the second modified intermediate value, a phase specific property of a phase of the multi-phase process fluid passing through the flowtube during the second period.

2. The method of claim 1, wherein the multi-phase process fluid comprises a wet gas during the first period and a liquid slug during the second period.

3. The method of claim 2, wherein the multi-phase process fluid comprises at least 95% gas by volume during the first period.

4. The method of claim 1, wherein the multi-phase process fluid further comprises more gas than liquid during a third period, and further comprising:

determining a third apparent property associated with the multi-phase process fluid during the third period, the third apparent property including an inaccuracy caused by the multi-phase process fluid passing through the flowmeter;

determining a third apparent intermediate value based on the third apparent property;

determining a third modified intermediate value based on the third apparent intermediate value, the third modified intermediate value at least partially correcting for the inaccuracy caused by the multi-phase process fluid passing through the flowmeter; and

determining, based on the third modified intermediate value, a phase-specific property of a phase of the multi-phase process fluid passing through the flowtube during the third period.

5. The method of claim 1, wherein determining a first modified intermediate value based on the first apparent intermediate value comprises inputting the first apparent intermediate value to a first mapping that defines a relationship between an apparent intermediate value and a modified intermediate value, and determining a second modified intermediate value based on the second apparent intermediate value comprises inputting the second apparent intermediate value to a second mapping.

6. The method of claim 5, wherein the first and second mappings are neural networks.

7. The method of claim 5, wherein the first mapping is trained with data obtained from a multi-phase fluid comprising more gas than liquid, and the second mapping is trained with data obtained from a multi-phase fluid comprising more liquid than gas.

8. The method of claim 1, wherein determining a phase-specific property of a phase of the multi-phase process fluid passing through the flowtube during the first period comprises determining a mass flowrate of a gas phase of the multi-phase process fluid, and determining a phase-specific property of the multi-phase process fluid passing through the flowtube during the second period comprises determining a mass flowrate of a liquid phase of the multi-phase process fluid.

9. The method of claim 1, wherein determining a phase-specific property of the multi-phase process fluid passing through the flowtube during the first period comprises determining a density of a gas phase of the multi-phase process fluid, and determining a phase-specific property of the multi-phase process fluid passing through the flowtube during the second period comprises determining a density of a liquid phase of the multi-phase process fluid.

10. The method of claim 1, wherein determining a phase-specific property of the multi-phase process fluid passing through the flowtube during the first period comprises determining the phase-specific property during the first period, and determining a phase-specific property of the multi-phase process fluid passing through the flowtube during the second period comprises determining the phase-specific property during the second period.

11. The method of claim 1, wherein the multi-phase process fluid comprises bubbles during the second period.

12. The method of claim 1, wherein the multi-phase process fluid comprises slug flow during the second period.

13. A flowmeter transmitter comprising:

at least one processing device; and

a storage device, the storage device storing instructions for causing the at least one processing device to;

induce motion in a vibratable flowtube through which a multi-phase process fluid passes, the multi-phase process fluid comprising more gas than liquid during a first period and more liquid than gas during a second period;

determine a first apparent property and a second apparent property of the multi-phase process fluid based on the motion of the vibratable flowtube, the first apparent property being associated with the multi-phase process fluid during the first period, the second apparent property being associated with the multi-phase fluid during the second period, and the first and second apparent properties incorporating respective inaccuracies caused by the multi-phase process fluid passing through the flowmeter;

determine a first apparent intermediate value based on the first apparent property and a second apparent intermediate value based on the second apparent property;

determine a first modified intermediate value based on the first apparent intermediate value and a second modified intermediate value based on the second apparent intermediate value, the first and second modified intermediate values at least partially correcting for the inaccuracy caused by the multi-phase process fluid passing through the flowmeter;

determine, based on the first modified intermediate value, a phase-specific property of a phase of the multi-phase process fluid passing through the flowtube during the first period; and

determine, based on the second modified intermediate value, a phase specific property of a phase of the multi-phase process fluid passing through the flowtube during the second period.

14. The transmitter of claim 13, wherein the multi-phase fluid comprises a wet gas during the first period and a liquid slug during the second period.

15. The transmitter of claim 14, wherein the multi-phase process fluid comprises at least 95% gas by volume during the first period.

16. The transmitter of claim 14, wherein the instructions for causing the at least one processing device to determine a first modified intermediate value based on the first apparent intermediate value comprise instructions to input the first apparent intermediate value to a first mapping that defines a relationship between an apparent intermediate value and a modified intermediate value, and the instructions to determine a second modified intermediate value based on the second apparent intermediate value comprise instructions to input the second apparent intermediate value to a second mapping.

17. The transmitter of claim 16, wherein the first mapping is trained with data obtained from a multi-phase fluid comprising more gas than liquid, and the second mapping is trained with data obtained from a multi-phase fluid comprising more liquid than gas.

18. A flowmeter comprising:

a vibratable flowtube through which a multi-phase process fluid passes, the multi-phase process fluid comprising more gas than liquid during a first period and more liquid than gas during a second period;

a driver connected to the flowtube and configured to impart motion to the flowtube;

a sensor connected to the flowtube and configured to sense the motion of the flowtube and generate a sensor signal; and

a controller to receive the sensor signal and configured to;

apply a drive signal to the driver to induce motion in the flowtube;

determine a first apparent property and a second apparent property of the multi-phase process fluid based on the motion of the vibratable flowtube, the first apparent property being associated with the multi-phase process fluid during the first period, the second apparent property being associated with the multi-phase fluid during the second period, and the first and second apparent properties incorporating respective inaccuracies caused by the multi-phase process fluid passing through the flowmeter;

determine a first apparent intermediate value based on the first apparent property and a second apparent intermediate value based on the second apparent property;

determine a first modified intermediate value based on the first apparent intermediate value and a second modified intermediate value based on the second apparent intermediate value, the first and second modified intermediate values at least partially correcting for the inaccuracy caused by the multi-phase process fluid passing through the flowmeter;

determine, based on the first modified intermediate value, a phase-specific property of a phase of the multi-phase process fluid passing through the flowtube during the first period; and

determine, based on the second modified intermediate value, a phase specific property of a phase of the multi-phase process fluid passing through the flowtube during the second period.

19. The flowmeter of claim 18, wherein the multi-phase fluid comprises a wet gas during the first period and a liquid slug during the second period.

20. The flowmeter of claim 19, wherein the multi-phase process fluid comprises at least 95% gas by volume during the first period.

21. The flowmeter of claim 18, wherein to determine a first modified intermediate value based on the first apparent intermediate value, the controller is configured to input the first apparent intermediate value to a first mapping that defines a relationship between an apparent intermediate value and a modified intermediate value, and, to determine a second modified intermediate value based on the second apparent intermediate value, the controller is configured to input the second apparent intermediate value to a second mapping.