Testing Protocol for Differential Pressure Measurement Devices API MPMS Chapter 22.2

Transcription

1 Testing Protocol for Differential Pressure Measurement Devices API MPMS Chapter 22.2 Steve Baldwin Chevron Energy Technology Company Houston, Texas USA Casey Hodges CEESI Measurement Solutions. Nunn, Colorado USA 1

2 Agenda History Development Overview Example of Testing Results Using API MPMS

3 History Differential producing meters have been around for over 100 years Orifice meters are the currently accepted differential meter for custody transfer metering Over 1000 studies have been performed on orifice meters to determine what factors influence the performance of the orifice meter 3

4 Factors Impacting Orifice Performance edge sharpness tap hole location tap hole characteristics pipe surface roughness plate surface roughness eccentricity of the bore flatness of the plate flow profile area ratio discharge coefficient / Reynolds number correlation 4

5 New Technologies To develop new technologies, similar levels of testing must be completed This would take years, and cost millions of dollars to perform and analyze the testing Manufacturers do not have the money to invest in the testing, and the industry does not want to wait decades to utilize new technologies Therefore the idea of a testing protocol was pursued Not as much testing as went into orifice Characterize the performance of the meter type 5

6 API MPMS 5.7 Published in 2003 Committee knew there would need to be changes made Testing would have to be performed to determine what changes needed to be made Major issues included better defining the test matrix and the determination of uncertainty 6

7 API MPMS Chapter 22 Chapter 22 represents a series of testing protocols 22.1 General guidelines for developing protocols 22.2 Differential Producing Flow Meters 22.3 Flare Gas Meters 22.4 Pressure, Differential Pressure, and Temperature Measurement Devices 22.5 Flow Computers 22.6 Gas Chromatographs 7

8 Current Status Several laboratories have conducted testing for a handful of manufacturers International interest in standard Currently under revision Some minor changes being made to close some loopholes and clarify some minor issues 8

9 Development of the Standard Objectives 1. Ensure that the user of any differential pressure flow meter knows the performance characteristics of the meter over a range of Reynolds numbers as applicable or defined by the tests 2. Facilitate both the understanding and the introduction of new technologies 3. Provide a standardized vehicle for validating manufacturer s performance specifications 4. Provide information about relative performance characteristics of the primary elements of the differential pressure metering device under standardized testing protocol 5. Quantify the uncertainty of these devices and define the operating and installation conditions for which the stated uncertainties apply 9

10 Characterization vs. Approval API MPMS 22.2 was developed not to have meters be approved, but to characterize the performance of the meter Results of testing does not encourage use of one meter over another Meter selection depends on factors such as application or costs, not results of 22.2 testing 10

11 Overview of API MPMS 22.2 Section 1 - Introduction Scope Objectives Definition of differential meters Examples of differential meters 11

12 Overview of API MPMS 22.2 Section 2 Definitions and Specific Terms Primary Element Secondary Devices Meter Asymmetry Swirl Beta / Area Ratio Others 12

13 Overview of API MPMS 22.2 Section 3 Installation and Test Facility Requirements Facility must meet 95% Uncertainty limit of RHG equation for orifice meters Does not eliminate manufacturer s lab Dimensional tolerances must be stated to determine the uncertainty of the meter If tolerances are not stated, each meter must be flow calibrated 13

14 Overview of API MPMS 22.2 Section 4 Meter Tests Meters to be tested 2 Line Sizes at least 2:1 ratio Two area ratios for each line size Suggested minimum 3:1 turndown in flowrate 10 points with 5 repeats at each point Acceptable Test Fluids Single phase, Newtonian fluids with known or measurable properties Liquid Flow Tests If testing on liquid, velocities not recommended to exceed 30 ft/s Only one pressure necessary 14

15 Overview of API MPMS 22.2 Section 4 Meter Tests (cont.) Gas Flow Tests Two line pressures with a 5:1 ratio Expansion factor testing Manufacturer defines limits of testing Low end often limited by dp measurement High end often limited by dp/p issues 15

16 Overview of API MPMS 22.2 Section 4 Meter Tests (cont.) Gas Flow (cont.) Baseline Test Fully Developed Flow Profile 30D Upstream + 5D Downstream Straight Pipe Establish performance of the meter Can be used to determine Cd for the meter 16

17 Overview of API MPMS 22.2 Section 4 Meter Tests (cont.) Gas Flow (cont.) Installation Effects Testing Downstream Disturbance Upstream Disturbance» Close coupled out-of-plane elbows» Half-moon orifice plate» Swirl (>24 ) generator Combined Upstream and Downstream Disturbance Special Installation Testing 17

18 Overview of API MPMS 22.2 Section 5 Laminar Flowmeter Tests Special type of differential producing meter Different equations and special requirements for testing Section 6 Flowrate Equation The equation used to determine the flowrate must be clearly stated by the manufacturer Range limits must be provided by the manufacturer Section 7 Procedure for Reporting Meter Performance Results Covers report format 18

19 Overview of API MPMS 22.2 Section 8 Uncertainty Calculations Uncertainty of the test facility Uncertainty of the meter determined from the results of the testing Combination of these uncertainties Appendix A Outlines the test matrix Appendix B Uncertainty examples 19

20 Example of Testing Baseline Test Discharge Coefficient Reynolds Number Baseline 20

21 Example: Half Moon 4D Upstream Discharge Coefficient Reynolds Number Baseline Installation Effect 21

22 Example: Half Moon 8D Upstream Discharge Coefficient Reynolds Number Baseline Installation Effect 22

23 Discharge Coefficient Determination Discharge Coefficient Reynolds Number Baseline Curve Fit Constant Cd 23

24 Using API MPMS 22.2 Several Issues Users Must Understand Care should be taken when analyzing results If the manufacturer does not want to calibrate each meter, level of testing increases Meter should be flow calibrated over the Reynolds number range it is going to be used Discharge coefficient determination 24

25 Conclusions API MPMS 22.2 was published in August 2005 and replaced API MPMS 5.7 Provides manufacturers and testing facilities with a method to verify the performance of the meter Provides users a method to compare specifications and performance of meters to choose the best meter for their application Users need to understand the standard to understand how to make proper decisions based on the standard Many factors influence the accuracy of a flow measurement, this standard just covers the primary differential producing device 25

26 Thank you for your attention Questions? Contact Information: Steve Baldwin Casey Hodges 26