Manual of Petroleum Measurement Standards Chapter 21—Flow Measurement

Using Electronic Metering Systems

Section 2—Electronic Liquid Volume

Measurement Using Positive Displacement and Turbine Meters

FIRST EDITION, JUNE 1998 REAFFIRMED, OCTOBER 2016

Manual of Petroleum Measurement Standards Chapter 21—Flow Measurement

Using Electronic Metering Systems

Section 2—Electronic Liquid Volume

Measurement Using Positive Displacement and Turbine Meters

Measurement Coordination

FIRST EDITION, JUNE 1998 REAFFIRMED, OCTOBER 2016

SPECIAL NOTES

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Copyright © 1998 American Petroleum Institute

FOREWORD

API publications may be used by anyone desiring to do so. Every effort has been made by the Institute to assure the accuracy and reliability of the data contained in them; however, the Institute makes no representation, warranty, or guarantee in connection with this publication and hereby expressly disclaims any liability or responsibility for loss or damage resulting from its use or for the violation of any federal, state, or municipal regulation with which this publication may conflict.

This standard is under the jurisdiction of the API Committee on Petroleum Measurement, Subcommittee on Liquid Measurement. This standard shall become effective January 1, 1999, but may be used voluntarily from the date of distribution. Suggested revisions are invited and should be submitted to the Measurement Coordinator, American Petroleum Insti- tute, 1220 L Street, N.W., Washington, D.C. 20005.

iii

1. Calibration Procedures 22

2. Verification Procedures 25

3. Ambient Temperature Considerations 26

1. SECURITY 27

   1. Access 27

   2. Restricting Access 27

   3. Integrity of Logged Data 27

   4. Algorithm Protection 27

   5. Memory Protection 27

APPENDIX A COMPUTER MATH HARDWARE AND SOFTWARE LIMITATIONS 29

APPENDIX B A/D CONVERTERS AND RESOLUTION 31

APPENDIX C EMERGENT STEM CORRECTION FOR LIQUID-IN-GLASS THERMOMETERS 33

APPENDIX D RESISTANCE VERSUS TEMPERATURE FOR INDUSTRIAL PLATINUM RTDS 35

APPENDIX E CALIBRATION AND VERIFICATION EQUIPMENT 37

APPENDIX F REQUIRED ACCURACY IN MEASURED TEMPERATURE, PRESSURE, AND DENSITY FOR DESIRED ACCURACY OF CORRECTION FACTORS CTL AND CPL 41

APPENDIX G UNCERTAINTY CALCULATIONS 57

Figures

1. Typical ELM System 5

2. Example of System Uncertainty Calculation 6

3. 100 Ohm RTD Tolerance Plots 23

B-1 A/D Counts vs. Sensor Input Showing Support for Over/Under

Range Regions 31

1. Example of System Uncertainty Calculation 57

2. Nonlinearity Example for NGL 58

Tables

1. Coefficients of Thermal Expansion for Steel (Gc, Ga, Gl) 16

2. Modulus of Elasticity for Steel Containers, E 17

B-1 A/D Converter Resolutions in Percent of Full Scale 31

1. Temperature Tolerance in °F for Generalized Crude Oil and JP4 to Maintain Accuracy in CTL of ±0.02 Percent Using API MPMS Chapter 11.1, Table 6A 42

2. Temperature Tolerance in °F for Generalized Crude Oil and JP4 to Maintain Accuracy in CTL of ±0.02 Percent Using API MPMS Chapter 11.1, Table 24A . . . 42

3. Temperature Tolerance in °C for Generalized Crude Oil and JP4 to Maintain Accuracy in CTL of ±0.02 Percent Using API MPMS Chapter 11.1, Table 54A . . . 42

4. Gravity Tolerance in °API for Generalized Crude Oil and JP4 to Maintain

   Accuracy in CTL of ±0.02 Percent Using API MPMS Chapter 11.1, Table 6A 43

5. Relative Density Tolerance for Hydrocarbon Liquids to Maintain Accuracy in

   CTL of ±0.02 Percent Using API MPMS Chapter 11.1, Table 24A 43

6. Density Tolerance for Hydrocarbon Liquids to Maintain Accuracy in CTL of

   ±0.02 Percent Using API MPMS Chapter 11.1, Table 54A 43

7. Temperature Tolerance in °F for Generalized Products to Maintain Accuracy

   in CTL of ±0.02 Percent Using API MPMS Chapter 11.1, Table 6B 44

   
   

   
   

8. Temperature Tolerance in °F for Generalized Products to Maintain Accuracy

   in CTL of ±0.02 Percent Using API MPMS Chapter 11.1, Table 24B 44

9. Temperature Tolerance in °C for Generalized Products to Maintain Accuracy

   in CTL of ±0.02 Percent Using API MPMS Chapter 11.1, Table 54B 44

10. Gravity Tolerance in °API for Generalized Products to Maintain Accuracy in

    CTL of ±0.02 Percent Using API MPMS Chapter 11.1, Table 6B 45

11. Relative Density Tolerance for Generalized Products to Maintain Accuracy in

    CTL of ±0.02 Percent Using API MPMS Chapter 11.1, Table 24B 45

12. Density Tolerance for Generalized Products to Maintain Accuracy in CTL of

    ±0.02 Percent Using API MPMS Chapter 11.1, Table 54B 45

13. Temperature Tolerance in °F for Lubricating Oils to Maintain Accuracy in

    CTL of ±0.02 Percent Using API MPMS Chapter 11.1, Table 6D 46

14. Temperature Tolerance in °C for Lubricating Oils to Maintain Accuracy in

    CTL of ±0.02 Percent Using API MPMS Chapter 11.1, Table 54D 46

15. Gravity Tolerance in °API for Lubricating Oils to Maintain Accuracy in

    CTL of ±0.02 Percent Using API MPMS Chapter 11.1, Table 6D 47

16. Density Tolerance for Lubricating Oils to Maintain Accuracy in CTL of

    ±0.02 Percent Using API MPMS Chapter 11.1, Table 54D 47

17. Temperature Tolerance in °F for Light Hydrocarbons to Maintain Accuracy in

    CTL of ±0.05 Percent Using GPA Research Report 148 48

18. Temperature Tolerance in °C for Light Hydrocarbons to Maintain Accuracy in

    CTL of ±0.05 Percent Using GPA Research Report 148 48

19. Relative Density Tolerance for Light Hydrocarbons to Maintain Accuracy in

    CTL of ±0.05 Percent Using GPA Research Report 148 49

20. Relative Density Tolerance for Light Hydrocarbons to Maintain Accuracy in

    CTL of ±0.05 Percent Using GPA Research Report 148 49

21. Pressure Tolerance in PSI for Hydrocarbon Liquids to Maintain Accuracy in

    CPL of ±0.02 Percent Using API MPMS Chapter 11.2.1 50

22. Pressure Tolerance in kPa for Hydrocarbon Liquids to Maintain Accuracy in

    CPL of ±0.02 Percent Using API MPMS Chapter 11.2.1M 50

23. Temperature Tolerance in °F for Hydrocarbon Liquids to Maintain Accuracy

    in CPL of ±0.02 Percent Using API MPMS Chapter 11.2.1 51

24. Temperature Tolerance in °C for Hydrocarbon Liquids to Maintain Accuracy

    in CPL of ±0.02 Percent Using API MPMS Chapter 11.2.1M 51

25. Gravity Tolerance in °API for Hydrocarbon Liquids to Maintain Accuracy

    in CPL of ±0.02 Percent Using API MPMS Chapter 11.2.1 52

26. Density Tolerance for Hydrocarbon Liquids to Maintain Accuracy in CPL of

    ±0.02 Percent Using API MPMS Chapter 11.2.1M 52

27. Pressure Tolerance in PSI for Hydrocarbon Liquids to Maintain Accuracy in

    CPL of ±0.02 Percent Using API MPMS Chapter 11.2.2 53

28. Pressure Tolerance in kPa for Hydrocarbon Liquids to Maintain Accuracy in

    CPL of ±0.02 Percent Using API MPMS Chapter 11.2.2M 53

29. Temperature Tolerance in °F for Hydrocarbon Liquids to Maintain Accuracy

    in CPL of ±0.02 Percent Using API MPMS Chapter 11.2.2 54

30. Temperature Tolerance in °C for Hydrocarbon Liquids to Maintain Accuracy

    in CPL of ±0.02 Percent Using API MPMS Chapter 11.2.2M 54

31. Relative Density Tolerance for Hydrocarbon Liquids to Maintain Accuracy in

    CPL of ±0.02 Percent Using API MPMS Chapter 11.2.2 55

32. Density Tolerance for Hydrocarbon Liquids to Maintain Accuracy in CPL of

±0.02 Percent Using API MPMS Chapter 11.2.2M 55

G-1 ELM System Uncertainty Example 60

Chapter 21—Flow Measurement Using Electronic Metering Systems Section 2—Electronic Liquid Volume Measurement Using Positive Displacement and Turbine Meters

1. Scope

   1. GENERAL

      1. This standard provides guidance for effective utiliza- tion of electronic liquid measurement systems for custody transfer measurement of liquid hydrocarbons:

         1. Within the scope and field of application of API MPMS

            Chapter 12.2.

         2. Which are single-phase liquids at measurement conditions.

         3. For systems utilizing turbine or positive displacement meters.

         4. For systems using on-line CTL and CPL compensation.

      2. The procedures and techniques discussed in this doc- ument are recommended for use with new measurement applications. Liquid measurement using existing equipment and techniques not in compliance with this standard may have a higher uncertainty than liquid measurement based on the recommendations contained in this document.

         
         

         1.2 ELECTRONIC LIQUID MEASUREMENT (ELM)

         The term “electronic liquid measurement,” or ELM, will be freely used throughout this document to denote liquid mea- surement using electronic metering systems. (Also see 3.20.)

         
         

2. Referenced Publications

   If the wording of this document conflicts with a referenced standard, the referenced standard will govern.

   API

   Manual of Petroleum Measurement Standards

   Chapter 1 “Vocabulary”

   Chapter 4 Section 2 “Conventional Pipe Provers” Chapter 4 Section 3 “Small Volume Provers”

   Chapter 4 Section 6 “Pulse Interpolation”

   Chapter 5 Section 2 “Measurement of Liquid Hydro-

   carbons by Displacement Meters” Chapter 5 Section 3 “Measurement of Liquid Hydro-

   carbons by Turbine Meters” Chapter 5 Section 4 “Accessory Equipment for Liquid

   Meters”

   Chapter 5 Section 5 “Fidelity and Security of Flow

   Measurement Pulsed-Data Trans- mission Systems”

   
   

   Chapter 11 “Physical Properties Data” Chapter 12 Section 2 “Calculation of Petroleum Quanti-

   ties Using Dynamic Measurement Methods and Volume Correction Factors”

   Chapter 13 “Statistical Aspects of Measuring and Sampling”

   Chapter 14 Section 6 “Continuous Density Measurement” Chapter 21 Section 1 “Electronic Gas Measurement” RP 500 Classification of Locations for

   Electrical Installations at Petro-

   leum Facilities Classified as Class 1, Division 1 and Division 2

   ASTM1

   D5002 Test Methods for Density and Rel- ative Density of Crude Oil by Dig- ital Density Analyzer

   
   

3. Definitions and Symbols

   1. INTRODUCTION

      The purpose of these definitions is to clarify the terminol- ogy used in the discussion of this standard only. The defini- tions are not intended to be an all-inclusive directory of terms used within the measurement industry, nor are they intended to conflict with any standards currently in use.

      
      

   2. WORDS AND TERMS

   3. accounting period: A duration of time usually of fixed length, such as a day or week, or the period of time required to transfer all or part of a batch.

   4. analog to digital (A/D) converter: A signal proces- sor that converts electrical analog signals to a corresponding digital number.

   5. accuracy: The extent to which the results of a calcu- lation or the readings of an instrument approach the true value.

   6. audit trail: The record of an electronic liquid measure- ment (ELM) system containing verification or calibration measurements for all tertiary and secondary devices, actual specifications for the primary device, constant values, times and dates of any changes affecting reported volumes and all

Chapter 7 Section 2 “Dynamic Temperature Determi-

nation”

Chapter 9 “Density Determination”

1American Society for Testing and Materials, 100 Barr Harbor Drive, West Conshohocken, Pennsylvania 19428.

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