1、Designation: D1657 121API Designation: Manual of Petroleum Measurement Standards (MPMS), Chapter 9.2Standard Test Method forDensity or Relative Density of Light Hydrocarbons byPressure Hydrometer1This standard is issued under the fixed designation D1657; the number immediately following the designat
2、ion indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTECorrected API MPMS naming convention thro
3、ughout editorially in October 2012.1. Scope*1.1 This test method covers the determination of the densityor relative density of light hydrocarbons including liquefiedpetroleum gases (LPG) having Reid vapor pressures exceeding101.325 kPa (14.696 psi).1.2 The prescribed apparatus should not be used for
4、 mate-rials having vapor pressures higher than 1.4 MPa (200 psi) atthe test temperature. This pressure limit is dictated by the typeof equipment. Higher pressures can apply to other equipmentdesigns.1.3 The initial pressure hydrometer readings obtained areuncorrected hydrometer readings and not dens
5、ity measure-ments. Readings are measured on a hydrometer at either thereference temperature or at another convenient temperature,and readings are corrected for the meniscus effect, the thermalglass expansion effect, alternate calibration temperature effectsand to the reference temperature by means o
6、f calculations andAdjunct to D1250 Guide for Petroleum Measurement Tables(API MPMS Chapter 11.1) or API MPMS Chapter 11.2.4 (GPATP-27), as applicable.1.4 Values determined as density or relative density can beconverted to equivalent values in the other units or alternativereference temperatures by m
7、eans of Interconversion Proce-dures API MPMS Chapter 11.5, or Adjunct to D1250 Guide forPetroleum Measurement Tables (API MPMS Chapter 11.1) orAPI MPMS Chapter 11.2.4 (GPA TP-27), as applicable.1.5 The calculations required in Section 11 shall be appliedto the initial pressure hydrometer reading wit
8、h observationsand results reported as required by Section 11 prior to use in asubsequent calculation procedure (measurement ticketcalculation, meter factor calculation, or base prover volumedetermination).1.6 Annex A1 contains a procedure for verifying or certify-ing the equipment for this test meth
9、od.1.7 The values in SI units are to be regarded as the standard.US Customary values shown in adjacent parentheses are forinformation only and may not be exactly equivalent. Both SIand customary units have been rounded so that they may not beexactly equivalent.1.8 This standard does not purport to a
10、ddress all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1250 Guide
11、 for Use of the Petroleum Measurement TablesD1265 Practice for Sampling Liquefied Petroleum (LP)Gases, Manual MethodD1298 Test Method for Density, Relative Density, and APIGravity of Crude Petroleum and Liquid Petroleum Prod-ucts by Hydrometer Method (API MPMS Chapter 9.1)E1 Specification for ASTM L
12、iquid-in-Glass ThermometersE100 Specification for ASTM Hydrometers2.2 API Standards:3MPMS Chapter 9.1 Test Method for Density, RelativeDensity, and API Gravity of Crude Petroleum and LiquidPetroleum Products by Hydrometer Method (ASTM TestMethod D1298)MPMS Chapter 11.1 Temperature and Pressure Volum
13、e Cor-rection Factors for Generalized Crude Oils, Refined Prod-ucts and Lubricating Oils (Adjunct to ASTM D1250)MPMS Chapter 11.2.2 Compressibility Factors for Hydro-carbons: 0.350-0.0637 Relative Density (60F/60F) and-50F to 140F Metering Temperature1This test method is under the jurisdiction of AS
14、TM Committee D02 onPetroleum Products and Lubricants and the API Committee on PetroleumMeasurement, and is the direct responsibility of Subcommittee D02.02 /COMQ, thejoint ASTM-API Committee on Hydrocarbon Measurement for Custody Transfer(Joint ASTM-API).Current edition approved June 1, 2012. Publis
15、hed August 2012. Originallyapproved in 1939. Last previous edition approved in 2007 as D165702(2007).DOI: 10.1520/D1657-12E01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information,
16、 refer to the standards Document Summary page onthe ASTM website.3Available from American Petroleum Institute (API), 1220 L. St., NW,Washington, DC 20005-4070, http:/www.api.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO B
17、ox C700, West Conshohocken, PA 19428-2959. United States1MPMS Chapter 11.2.2M Compressibility Factors for Hydro-carbons: 350-637 Kilograms per Cubic Meter Density15C and -46C to 60C Metering TemperaturesMPMS Chapter 11.2.4 Temperature Correction for the Vol-ume of NGL and LPG Tables 23E, 24E, 53E, 5
18、4E, 59Eand 60E (joint standard with GPA TP-27)MPMS Chapter 11.5 Density/Weight/Volume Intraconver-sion2.3 GPA Standards:4GPA Technical Publication TP-27 Temperature Correctionfor the Volume of NGL and LPG, Tables 23E, 24E, 53E,54E, 59E and 60E (joint standard with API MPMSChapter 11.2.4)2.4 ASTM Adj
19、uncts:Adjunct to D1250 Guide for Petroleum Measurement Tables(API MPMS Chapter 11.1)53. Terminology3.1 Definitions:3.1.1 density, nthe mass of liquid per unit volume at 15Cand its saturation pressure with the standard unit of measure-ment being kilograms per cubic metre.3.1.1.1 DiscussionOther refer
20、ence temperatures, such as20C may be used for some products or in some locations. Lesspreferred units of measurement; for example, kg/Lor g/mL, arestill in use.3.1.2 relative density (specific gravity), nthe ratio of themass of a given volume of liquid at a specific temperature tothe mass of an equa
21、l volume of pure water at the same ordifferent temperature. Both reference temperatures shall beexplicitly stated.3.1.2.1 DiscussionCommon reference temperatures in-clude 60/60F, 20/20C, 20/4C. The historic deprecated term“specific gravity” may still be found.3.1.3 thermohydrometer, na glass hydrome
22、ter with a self-contained mercury thermometer.4. Summary of Test Method4.1 The apparatus is purged with a portion of the samplebefore filling with the portion to be used for testing. Thepressure cylinder is filled to a level at which the enclosedhydrometer floats freely, and the cylinder is then pla
23、ced in aconstant-temperature bath (if needed). When the temperaturehas reached equilibrium, the hydrometer reading and thetemperature of the sample are read. The observed hydrometerreading is corrected for the meniscus effect, alternate calibra-tion temperature effects and reduced to the reference t
24、empera-ture by means of the volume correction factors or tables asapplicable by use of the appropriate Adjunct to D1250 Guidefor Petroleum Measurement Tables (API MPMS Chapter 11.1)or API MPMS Chapter 11.2.4 (GPA TP-27), as applicable, andobserved temperature from the thermometer.5. Significance and
25、 Use5.1 The density or relative density of light hydrocarbons andliquefied petroleum gases is used in custody transfer quantitycalculations or to satisfy transportation, storage, and regulatoryrequirements.6. Apparatus6.1 Hydrometers, graduated in density with a range from500 to 650 kg/m3, or in rel
26、ative density with a range from0.500 to 0.650, and conforming to the dimensions in Specifi-cation E100.6.1.1 Thermohydrometers, for field applications, thermohy-drometers may be more convenient than hydrometers withseparate thermometers. They shall conform to SpecificationE100, Thermohydrometer Nos.
27、 101H or 310H.6.1.1.1 Thermohydrometers shall be of suitable range andhave dimensions to float freely within the pressure hydrometercylinder with clearances of 5 mm at the wall and 25 mm at thetop and bottom.6.1.1.2 The test report shall state that a thermohydrometerwas used.6.1.1.3 The user should
28、ascertain that the instruments usedfor this procedure conform to the requirements set out abovewith respect to materials, dimensions, and scale errors. In caseswhere the instrument is provided with a calibration certificateissued by a recognized standardizing body, the instrument isclassed as certif
29、ied and the appropriate corrections for themeniscus effect, the thermal glass expansion effect, and alter-native calibration temperature effects shall be applied to theobserved readings prior to corrections. Instruments that satisfythe requirements of this test method, but are not provided witha rec
30、ognized calibration certificate, are classed as uncertifiedand the appropriate corrections for the meniscus effect, thethermal glass expansion effect, and alternative calibrationtemperature effects shall be applied to the observed readingsprior to corrections.6.2 Hydrometer Cylinder, constructed of
31、transparent plastic;for example, poly(methyl methacrylate) or equivalent material,conforming to the design and recommended dimensions givenin Fig. 1. The cylinder shall be of such dimensions that thehydrometer shall float freely within it. The ends shall be tightlysealed with neoprene gaskets and me
32、tal end plates as shown inFig. 1.(WarningA protective shield shall be placed aroundthe cylinder. Replace any cylinders that show signs of fogging,crazing, cracking, or etching.)NOTE 1Certain compounds attack plastics and cloud the inner surfaceof the cylinder, making it difficult or impossible to re
33、ad the hydrometer.Tests showed no attack by ethane, ethene (ethylene), propane, propylene,butane, methylpropane (isobutane), butenes (normal butylenes), methyl-propene (isobutylene), pentane, and methylbutane (isopentane), and noattack is expected from butadiene and acetaldehyde. Users are cautioned
34、,however, to clean the cylinder thoroughly after each determination.Ketones and alcohols should not be used for cleaning as they attack andweaken plastics while aromatics also tend to attack the surface of plasticsand should similarly not be used. A light aliphatic hydrocarbon isrecommended for clea
35、ning. (WarningExtremely flammable. Harmful ifinhaled. Vapors may cause flash fire.)6.2.1 The liquid inlet valve and the liquid outlet valve shallbe tightly connected to a base plate that shall be bored to give4Available from Gas Processors Association (GPA), 6526 E. 60th St., Tulsa, OK74145, http:/w
36、ww.gpaglobal.org.5Available from ASTM International Headquarters. Order Adjunct No.ADJD1250. Original adjunct produced in 1983.D1657 1212both valves a common inlet to the cylinder. The vapor ventvalve shall be similarly connected to the top plate, which shallbe bored to provide a vapor outlet from t
37、he pressure cylinder.All valves shall be 6 mm (14 in.) or equivalent needle valves.6.2.2 The cylinder shall not be operated at a gage pressuregreater than 1.4 MPa (200 psi). A hydrostatic test at 2.8 MPa(400 psi) shall be carried out at intervals no greater than 12months.FIG. 1 Pressure Hydrometer C
38、ylinderD1657 1213NOTE 2For SafetyThe cylinder should be equipped with appropri-ate safety devices to prevent over-pressure. Consideration should be givento pressure testing the cylinder at 1.25 to 1.5 times its normal maximumoperating pressure on a periodic basis, not to exceed two years.6.3 Thermom
39、eters, conforming to ASTM 12C or 12F inSpecification E1. The thermometer shall be held firmly insidethe hydrometer cylinder by a clip in such a manner that it doesnot interfere with the free movement of the hydrometer.6.4 Constant-Temperature Bath, of dimensions such that itcan accommodate the hydro
40、meter cylinder with the test portionfully immersed below the test portion liquid surface, and atemperature control system capable of maintaining the bathtemperature within 0.25C of the test temperature throughoutthe duration of the test.7. Reference Liquids7.1 The following reference liquids are req
41、uired for stan-dardization of the hydrometer:7.1.1 Propane, pure grade, having a nominal density of507.6 kg/m3at 15C or a relative density 60/60F of 0.50699.(WarningExtremely flammable. Harmful if inhaled. Vaporsmay cause flash fire.) The density of the reference liquid usedshall be known.7.1.2 Buta
42、ne, pure grade, having a nominal density of584.1 kg/m3at 15C or a relative density 60/60F of 0.5840.(WarningExtremely flammable. Harmful if inhaled. Vaporsmay cause flash fire.) The density of the reference liquid usedshall be known.8. Sampling8.1 Unless otherwise specified, samples of liquid hydroc
43、ar-bons shall be obtained by the procedures described in PracticeD1265. The procedure for sampling for verification of theapparatus and for subsequent testing is described as follows.8.1.1 Connect the source of supply of the liquid to be testedto the inlet valve by suitable fittings so that a repres
44、entativesample can be introduced into the cylinder.Ascertain that theseconnections are free of leaks. Open the outlet and vent valvesand purge the sampling connections by opening the inlet valveslightly, permitting the product to flow through the outlet valveat the bottom of the cylinder and the ven
45、t valve at the top of thecylinder.8.1.2 When the connections have been purged, close theoutlet and vent valves and open the inlet valve, permitting theliquid to enter the cylinder until it is full. If necessary, the ventvalve may be opened slightly to permit complete filling of thecylinder after whi
46、ch it shall be closed. At no time shall thepressure in the cylinder be allowed to rise above a gagepressure of 1.4 MPa (200 psi).8.1.3 When the cylinder has been filled, close the inlet valveand open the outlet and vent valves, permitting the contents ofthe cylinder to be withdrawn completely and th
47、e pressureinside the cylinder to be returned to atmospheric pressure.8.1.4 Close the outlet and vent valves and open the inletvalve, filling the cylinder to a level at which the enclosedhydrometer floats freely. If it is necessary to accomplish thisfilling by venting vapor through the vent valve, re
48、peat thepurging to cool the cylinder sufficiently to permit its beingfilled without venting.8.1.5 With all valves closed, examine the apparatus forleaks. If leaks are detected, discard the sample, reduce thepressure to atmospheric and repair the leaks. Repeat thesampling procedure.9. Verification of
49、 Apparatus9.1 Carefully clean and dry the hydrometer and the insidewall of the pressure cylinder.9.2 Insert the hydrometer in the pressure cylinder and attachthe thermometer and cover plate. Connect the source of supplyof the reference liquid to the inlet valve and ascertain that theconnections are free of leaks. Fill the hydrometer with one ofthe reference fluids (see Section 7) by the procedure given in8.1.2-8.1.5.9.3 Disconnect the hydrometer cylinder from the source ofsupply of liquid and place it in the constant-temperature bathmaintained w
