1、Manual of PetroleumMeasurement StandardsChapter 14Natural Gas Fluids MeasurementSection 8Liquefied Petroleum Gas MeasurementSECOND EDITION, JULY 1997REAFFIRMED, OCTOBER 2011Manual of PetroleumMeasurement StandardsChapter 14Natural Gas Fluids MeasurementSection 8Liquefied Petroleum Gas MeasurementMea
2、surement CoordinationSECOND EDITION, JULY 1997REAFFIRMED, OCTOBER 2011SPECIAL NOTESAPI publications necessarily address problems of a general nature. With respect to partic-ular circumstances, local, state, and federal laws and regulations should be reviewed.API is not undertaking to meet the duties
3、 of employers, manufacturers, or suppliers towarn and properly train and equip their employees, and others exposed, concerning healthand safety risks and precautions, nor undertaking their obligations under local, state, orfederal laws.Information concerning safety and health risks and proper precau
4、tions with respect to par-ticular materials and conditions should be obtained from the employer, the manufacturer orsupplier of that material, or the material safety data sheet.Nothing contained in any API publication is to be construed as granting any right, byimplication or otherwise, for the manu
5、facture, sale, or use of any method, apparatus, or prod-uct covered by letters patent. Neither should anything contained in the publication be con-strued as insuring anyone against liability for infringement of letters patent.Generally, API standards are reviewed and revised, reaffirmed, or withdraw
6、n at least everyfive years. Sometimes a one-time extension of up to two years will be added to this reviewcycle. This publication will no longer be in effect five years after its publication date as anoperative API standard or, where an extension has been granted, upon republication. Statusof the pu
7、blication can be ascertained from the API Measurement Coordination telephone(202) 682-8146. A catalog of API publications and materials is published annually andupdated quarterly by API, 1220 L Street, N.W., Washington, D.C. 20005.This document was produced under API standardization procedures that
8、ensure appropri-ate notification and participation in the developmental process and is designated as an APIstandard. Questions concerning the interpretation of the content of this standard or com-ments and questions concerning the procedures under which this standard was developedshould be directed
9、in writing to the Measurement Coordinator, Exploration and ProductionDepartment, American Petroleum Institute, 1220 L Street, N.W., Washington, D.C. 20005.Requests for permission to reproduce or translate all or any part of the material publishedherein should also be addressed to the director.API st
10、andards are published to facilitate the broad availability of proven, sound engineer-ing and operating practices. These standards are not intended to obviate the need for apply-ing sound engineering judgment regarding when and where these standards should beutilized. The formulation and publication
11、of API standards is not intended in any way toinhibit anyone from using any other practices.Any manufacturer marking equipment or materials in conformance with the markingrequirements of an API standard is solely responsible for complying with all the applicablerequirements of that standard. API doe
12、s not represent, warrant, or guarantee that such prod-ucts do in fact conform to the applicable API standard.All rights reserved. No part of this work may be reproduced, stored in a retrieval system, or transmitted by any means, electronic, mechanical, photocopying, recording, or otherwise, without
13、prior written permission from the publisher. Contact the Publisher, API Publishing Services, 1220 L Street, N.W., Washington, D.C. 20005.Copyright 1997 American Petroleum InstituteiiiFOREWORDAPI publications may be used by anyone desiring to do so. Every effort has been madeby the Institute to assur
14、e the accuracy and reliability of the data contained in them; how-ever, the Institute makes no representation, warranty, or guarantee in connection with thispublication and hereby expressly disclaims any liability or responsibility for loss or dam-age resulting from its use or for the violation of a
15、ny federal, state, or municipal regulationwith which this publication may conflict.Suggested revisions are invited and should be submitted to Measurement Coordination,American Petroleum Institute, 1220 L Street, N.W., Washington, D.C. 20005.CONTENTSPageSECTION 8LIQUEFIED PETROLEUM GAS MEASUREMENT 11
16、 SCOPE AND PURPOSE . 12 REFERENCED PUBLICATIONS 13 APPLICATION 24 REQUIREMENTS FOR ALL MEASUREMENT METHODS . 24.1 Provisions to Ensure That Fluids are in the Liquid Phase 24.2 Elimination of Swirl. 24.3 Temperature Measurement. 24.4 Pressure Measurement 34.5 Density or Relative Density Measurement.
17、34.6 Location of Measuring and Sampling Equipment . 35 VOLUMETRIC DETERMINATION IN DYNAMIC SYSTEMS 35.1 Measurement by Orifice Meter 35.2 Measurement by Positive Displacement Meter 65.3 Measurement by Turbine Meter . 65.4 Measurement by Other Devices . 65.5 Meter Proving. 65.6 Sampling 75.7 Sample A
18、nalysis . 76 MASS DETERMINATION IN DYNAMIC SYSTEMS 86.1 Base Conditions . 86.2 Mass Measurement Using Displacement Type or Turbine Meters 86.3 Orifice Meters for Mass Measurement. 86.4 Density Determination . 96.5 Conversion of Measured Mass to Volume 107 VOLUMETRIC MEASUREMENT IN STATIC SYSTEMS 107
19、.1 Tank Calibration. 107.2 Tank Gauging of Liquefied Petroleum Gas 107.3 Temperature Measurement. 107.4 Relative Density Measurement. 107.5 Water and Foreign Material 117.6 Sampling 117.7 Volumetric Calculation. 117.8 Mixture Calculation . 128 MASS MEASUREMENT IN STATIC SYSTEMS. 12APPENDIX A COMPONE
20、NT SAMPLE CALCULATIONS . 13Figure1 Calculations for Liquid Vapor Conversion 15Table1 Linear Coefficient of Thermal Expansion 5Index. 17vCONTENTSPage1Chapter 14Natural Gas Fluids MeasurementSECTION 8LIQUEFIED PETROLEUM GAS MEASUREMENT1 Scope and PurposeThis publication describes dynamic and static me
21、asure-ment systems used to measure liquefied petroleum gas(LPG) in the relative density range of 0.350 to 0.637 (seeChapter 11.2.2). The physical properties of the componentsto be measured and the mixture composition of liquefiedpetroleum gas should be reviewed to determine the measure-ment system t
22、o be used. Various systems and methods canbe used in measuring the quantity of product, and mutualagreement on the system and method between the contract-ing parties is required.This publication does not endorse or advocate the pref-erential use of any specific type of meter or metering sys-tem. Fur
23、ther, this publication is not intended to restrict thefuture development of meters or measuring devices, nor toin any way affect metering equipment already installed andin operation.This publication serves as a guide in the selection, installa-tion, operation, and maintenance of measuring systems ap
24、pli-cable to liquefied petroleum gases and includes functionaldescriptions for individual systems.2 Referenced PublicationsTo the extent specified in the text, the latest edition or revi-sion of the following standards and publications form a partof this publication.APIManual of Petroleum Measuremen
25、t Standards (MPMS)Chapter 2Tank CalibrationChapter 3Tank GaugingChapter 4Proving SystemsChapter 5.2Measurement of Liquid Hydrocarbons byDisplacement MetersChapter 5.3Measurement of Liquid Hydrocarbons byTurbine MetersChapter 5.4Accessory Equipment for Liquid MetersChapter 6.6Pipeline Metering System
26、sChapter 7.2Dynamic Temperature DeterminationChapter 8SamplingChapter 9Density DeterminationChapter 9.2Pressure Hydrometer Test Method forDensity or Relative DensityChapter 11.2.2Compressibility Factors for Hydrocar-bons: 0.350-0.637 Relative Density (60/60F) and 50F to 140F MeteringTemperatureChapt
27、er 12.2Calculation of Liquid Petroleum Quanti-ties Measured by Turbine or Displace-ment MetersChapter 14.3Concentric Square-Edged Orifice Meters(A.G.A. Report No. 3) (GPA 8185-90)Chapter 14.4Converting Mass of Natural Gas Liquidsand Vapors to Equivalent Liquid VolumesChapter 14.6Continuous Density M
28、easurementChapter 14.7Mass Measurement of Natural Gas LiquidsASM Intl1Metals HandbookASME2Performance Test Code 19.5 (current edition)ASTM3D 1250-80Volume XII, Table 34Reduction of Vol-ume to 60F Against Specific Gravity 60/60F for Liquefied Petroleum GasesD 2713-91Test Method for Dryness of Propane
29、(Valve Freeze Method)GPA42140Liquefied Petroleum Gas Specificationsand Test Methods (ASTM D 1835; ANSIZ11.91)2142Standard Factors for Volume Correctionand Specific Gravity Conversion of Liq-uefied Petroleum Gases2145Physical Constants for Paraffin Hydro-carbons and Other Components of Natu-ral Gas21
30、65Standard for Analysis of Natural GasLiquid Mixtures by Gas Chromatography2166Obtaining Natural Gas Samples forAnalysis by Gas Chromatography2174Method for Obtaining Liquid Hydrocar-bon Samples Using a Floating PistonCylinder2177Analysis of Demethanized HydrocarbonLiquid Mixtures Containing Nitroge
31、n andCarbon Dioxide by Gas Chromatography2186Tentative Method for the Extended Anal-ysis of Hydrocarbon Liquid MixturesContaining Nitrogen and Carbon Diox-1ASM International, 9639 Kinsman Road, Materials Park, Ohio 44073-0002.2American Society of Mechanical Engineers, 345 East 47th Street, NewYork,
32、New York 10017-2392.3ASTM, 100 Bar Harbor Drive, West Conshohocken, Pennsylvania 19428.4Gas Processors Association, 6526 E. 60th Street, Tulsa, Oklahoma 74145. 2CHAPTER14NATURALGASFLUIDSMEASUREMENTide by Temperature Programmed GasChromatography2261Analysis for Natural Gas and SimilarGaseous Mixtures
33、 by Gas Chromatogra-phy 2286Tentative Method of Extended Analysisfor Natural Gas and Similar GaseousMixtures by Temperature ProgrammedGas Chromatography8173Method for Converting Mass NaturalGas Liquids and Vapors to EquivalentLiquid Volumes8182-95Standard for the Mass Measurement ofNational Gas Liqu
34、idsGPSA5Engineering Data Book3 ApplicationThis publication does not set tolerances or accuracy limits.The application of the information here should be adequate toachieve acceptable measurement performance using goodmeasurement practices, while also considering user require-ments and applicable code
35、s and regulations.Systems for measuring liquefied petroleum gases useeither volumetric or mass determination methods, and bothmethods apply to either static or dynamic conditions.Mass determination methods of measurement are mostcommonly used where conditions in addition to temperatureand pressure w
36、ill affect the measurement. Such conditionsinclude compositional changes, intermolecular adhesion, andvolumetric changes caused by solution mixing. Mass mea-surement is applicable to liquefied petroleum gas mixtureswhere accurate physical correction factors have not beendetermined, and to some manuf
37、acturing processes for massbalance determination.Volumetric methods of measurement are generally usedwhere physical property changes in temperature and pressureare known and correction factors can be applied to correct themeasurement to standard conditions.6,7Volumetric measure-ment is applicable to
38、 most pure components and many com-mercial product grades.Many of the measurement procedures pertaining to themeasurement of other products are applicable to the measure-ment of liquefied petroleum gases. However, certain charac-teristics of liquefied petroleum gas require extra precautionsto improv
39、e measurement accuracy.Liquefied petroleum gas will remain in the liquid state onlyif a pressure sufficiently greater than the equilibrium vaporpressure is maintained (see Chapters 5.3 and 6.6). In liquidmeter systems, adequate pressure must be maintained to pre-vent vaporization caused by pressure
40、drops attributed to pip-ing, valves, and meter tubes. When liquefied petroleum gas isstored in tanks or containers, a portion of the liquid willvaporize and fill the space above the liquid. The amountvaporized will be related to the temperature and the equilib-rium constant for the mixture of compon
41、ents.Liquefied petroleum gas is more compressible and has agreater coefficient of thermal expansion than the heavierhydrocarbons. The application of appropriate compressibilityand temperature correction factors is required to correct mea-surements to standard conditions, except when measurementfor m
42、ass determination is from density and volume at meter-ing temperatures and pressures.Meters should be proven on each product at or near thenormal operating temperature, pressure, and flow rate. If theproduct or operating conditions change so that a significantchange in the meter factor occurs, the m
43、eter should be provenagain according to Chapters 4 and 5.4 Requirements For All Measurement MethodsThe following general requirements apply to dynamicmeasurement systems using either volumetric or mass deter-mination methods of measuring liquefied petroleum gases.4.1 PROVISIONS TO ENSURE THAT FLUIDS
44、 AREIN THE LIQUID PHASEProvisions shall be made to ensure liquefied petroleum gasmeasurement conditions of temperature and pressure will beadequate to keep the fluid totally in the liquid phase. For mea-surement in the liquid phase, the pressure at the meter inletmust be at least 1.25 times the equi
45、librium vapor pressure atmeasurement temperature, plus twice the pressure dropacross the meter at maximum operating flow rate, or at a pres-sure 125 pounds per square inch higher than the vapor pres-sure at a maximum operating temperature, whichever is lower(see Chapters 5.3 and 6.6).4.2 ELIMINATION
46、 OF SWIRLWhen using turbine or orifice meters, the installationshall comply with the requirements specified in chapters5.3 or 14.3, respectively.4.3 TEMPERATURE MEASUREMENTUse of a fixed temperature may be acceptable, in somecases, when it varies by only a small amount; however, acontinuously measur
47、ed temperature is recommended formaximum accuracy.5Gas Processors Suppliers Association; Order from Gas Processors Associa-tion, 6526 E. 60th Street, Tulsa, Oklahoma 74145.6USA SystemStandard temperature is 60 F and standard pressure is thevapor pressure at 60 F or 14.696 pounds per square inch abso
48、lute, whicheveris higher. This is not the same pressure base standard as that used for gas.7International System of Units (SI)Standard temperature is 15 C and stan-dard pressure is the vapor pressure at 15 C or 101.325 kilopascals, whicheveris higher.SECTION8LIQUEFIEDPETROLEUMGASMEASUREMENT3Temperat
49、ure measurements, where required, should bemade at a point that indicates flowing conditions in the mea-suring device. The accuracy of instruments and the type ofmeasurement used are specified in Chapters 4, 5.2, 5.3, 5.4,7.2, and 14.6.4.4 PRESSURE MEASUREMENTUse of a fixed pressure may be acceptable in some cases,where it varies by only a small amount; however, a continu-ously measured pressure is recommended for maximumaccuracy. Pressure measurements, where required, should be madeat a point that will be responsive to varying pressure condi-tions in the measuring devic
