Testing Protocol for Differential Pressure Measurement ... · 1 Testing Protocol for Differential Pressure Measurement Devices API MPMS Chapter 22.2 . Casey Hodges . CEESI Measurement

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Testing Protocol for Differential Pressure Measurement Devices

API MPMS Chapter 22.2

Casey Hodges CEESI Measurement

Solutions. Nunn, Colorado USA

Steve Baldwin Chevron

Energy Technology Company

Houston, Texas USA

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Agenda

• History • Development • Overview • Example of Testing Results • Using API MPMS 22.2

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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

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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

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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

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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

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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

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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

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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

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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

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Overview of API MPMS 22.2

• Section 1 - Introduction – Scope – Objectives – Definition of differential meters – Examples of differential meters

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Overview of API MPMS 22.2

• Section 2 – Definitions and Specific Terms – Primary Element – Secondary Devices – Meter Asymmetry – Swirl – Beta / Area Ratio – Others

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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

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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

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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

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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

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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

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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

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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

0.590

0.595

0.600

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0.645

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Reynolds Number

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Baseline20

Example of Testing Baseline Test

0.590

0.595

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Baseline Installation Effect

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Example: Half Moon 4D Upstream

0.590

0.595

0.600

0.605

0.610

0.615

0.620

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0.635

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0 50000 100000 150000 200000 250000 300000 350000

Reynolds Number

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Baseline Installation Effect

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Example: Half Moon 8D Upstream

0.600

0.605

0.610

0.615

0.620

0.625

0.630

0.635

0.640

0.645

0 50000 100000 150000 200000 250000 300000 350000

Reynolds Number

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Baseline Curve Fit Constant Cd23

Discharge Coefficient Determination

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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

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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

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Thank you for your attention

Questions?

Contact Information: Steve Baldwin

[email protected] Casey Hodges

[email protected]