1、Manual of Petroleum Measurement Standards Chapter 14Natural Gas Fluid MeasurementSection 12Measurement of Gas by Vortex MetersFIRST EDITION, MARCH 2017Special NotesAPI publications necessarily address problems of a general nature. With respect to particular circumstances, local, state, and federal l
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16、annually by API, 1220 L Street, NW, Washington, DC 20005.Suggested revisions are invited and should be submitted to the Standards Department, API, 1220 L Street, NW, Washington, DC 20005, standardsapi.org.iiiContentsPage1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Normative References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Terms, Definitions, Symbols, and Abbreviation
18、s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23.1 Terms and Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23.2 Symbols . . . . . . . . . . . . . . .
19、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43.3 Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20、 . 64 Field of Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64.1 General Characteristics of the Vortex Flow Measurement Technology. . . . . . . . . . . . . . . . . . . . . . . . . . . . 74.2
21、Principle of Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 Flowmeter Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
22、. . . . . . . . 95.1 Physical Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95.2 Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
23、. . . . . . . . . . . . . . . . . . . . . . . . 116 Design and Installation Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146.1 Meter Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
24、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146.2 Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157 Operation and Performance. . . . . . . . . . . . . . . . .
25、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187.1 Process Influences. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187.2 Operation. . . . . . . . . . . . . . .
26、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197.3 Effect of Process Fluid Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197.4 Mechanical Ch
27、aracteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197.5 Performance Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207.6
28、 Quantity Computations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208 Proving, Calibration, and Performance Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218.
29、1 Factory Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218.2 Field Calibration/Verification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
30、 . . . . . . . . . . 219 Uncertainty CalculationVortex Meter Flow Measurement Uncertainty Analysis Procedure. . . . . . . . . 2210 Auditing and Reporting Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Annex A (normative) Fac
31、tory Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Annex B (informative) Proving Form for Meter Output (Numerical Example in the US Customary Units) . . . 26Annex C (informative) System Uncertainty. . . . . . . . . . . .
32、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27Annex D (informative) Special Considerations for Steam. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31Annex E (informative) Period Jitter and Its Effect on Calibration. .
33、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32Annex F (informative) Experimental Data Showing Pressure Tap Location Effect on K-factor . . . . . . . . . . . 34Figures1 Vortex Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
34、 . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 Vortex Shedder Cross Sections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 Example of Vortex Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
35、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 The 420mA and Pulse Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 Raw Pulse Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
36、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126 Schematic Showing Recommended Pressure and Temperature Tap Locations. . . . . . . . . . . . . . . . . . . . 17vContentsPage7 Example of a K-factor Curve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
37、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20C.1 An Example of Calibration Data Plot of a Vortex Meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29D.1 Improper Installation for Saturated Steam . . . . . . . . . . . . . . . . . . . . . . . . . . .
38、. . . . . . . . . . . . . . . . . . . . . . . . 31F.1 K vs Velocity Using Inlet Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34F.2 K vs Velocity Using Downstream Pressure . . . . . . . . . . . . . . . . . . . . . . . . . .
39、 . . . . . . . . . . . . . . . . . . . . . . . . 34F.3 Error in K-factor Using Inlet Pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35F.4 Error in K-factor Using Downstream Pressure . . . . . . . . . . . . . . . . . . . . . . . .
40、 . . . . . . . . . . . . . . . . . . . . . . . 35Tables1 Symbols and Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4E.1 Time (sec), a, Needed for a Flow Rate Uncertainty of 0.25 % . . . . . . . . . . . . .
41、 . . . . . . . . . . . . . . . . . . . . . . 33IntroductionThis document describes the design, installation and operation of vortex shedding flowmeters for the measurement of hydrocarbon gases and steam flows.Vortex shedding is a flow phenomenon that occurs when a bluff body is placed in flowing flu
42、id and depending on the size and shape of a bluff body, under certain flowing conditions, alternating vortices are created on the downstream side of the body and detach periodically from either side of the body. The fluid flow past the object, often referred to as the vortex shedder, creates alterna
43、ting low-pressure vortices on the downstream side of the object.The vortex shedding frequency, with a few exceptions, is proportional to flow rate. Hence, by monitoring the shedding frequency and through numerical computational techniques, the fluid velocity and flow rate at the actual flowing condi
44、tions can be determined.vi1Chapter 14Natural Gas Fluid MeasurementSection 12Measurement of Gas by Vortex Meters1 ScopeThis Standard addresses the following:a) provides generic information on full-bore vortex shedding flowmeters, including glossary, and sets of engineering equations useful in specify
45、ing performance;b) describes vortex shedding flowmeters in which alternating vortices are shed from one or more bluff bodies installed in a closed conduit;c) describes how the vortex shedding frequency is used to determine the velocity to infer the volume, mass, and/or energy flow rate and the total
46、 gas flow through the meter over a specific time interval;d) applies only to single phase gas flows in closed conduit that are steady or vary slowly in time. For fiscal measurement, the output of the flow rate shall be within the acceptable limits of steady state flow rate;e) describes the physical
47、components of vortex shedding flowmeters and identifies need for inspection, certification, and material traceability;f) addresses the effect of gas properties, installation, and process conditions that may affect the measurement uncertainty and describes guidelines for reducing or eliminating their
48、 influences;g) defines the method for calculating uncertainty of the flow rate measurement;h) defines the meter output requirements and necessary information pertaining to the meter output for the purpose of fiscal measurement of gas; andi) provides calibration and/or performance verification guidan
49、ce for the field application.2 Normative ReferencesThe following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.API MPMS Chapter 4.5, Master Meter Provers, 2011API MPMS Chapter 4.2, Displacement Provers, Reaffirmed 2011API MPMS Chapter 14.2, AGA Report No. 8/GPA 8185, Compressibility Factors of Natural Gas and other Related Hydrocarbon Gases, Reaffirmed 2012 2 API MPMS CHAPTER 14NATURAL GAS FLUID
