1、Designation: D1657 12Designation: 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 designation i
2、ndicates 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.1. Scope*1.1 This test method covers the determinat
3、ion 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 mate-rials having vapor pressures higher than 1.4 MPa (200 psi) atthe test temperatur
4、e. 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 density measure-ments. Readings are measured on a hydrometer at either thereference temper
5、ature 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 of calculations andAdjunct to ASTM D1250/API MPMS Chapter 11.1.1.4 Values determined as
6、 density or relative density can beconverted to equivalent values in the other units or alternativereference temperatures by means of Interconversion Proce-dures, or Adjunct to ASTM Guide D1250/API MPMS Chapter11.1, or both, or tables as applicable.1.5 The calculations required in Section 11 shall b
7、e appliedto the initial pressure hydrometer reading with observationsand results reported as required by Section 11 prior to use in asubsequent calculation procedure (measurement ticket calcula-tion, meter factor calculation, or base prover volume determi-nation).1.6 Annex A1 contains a procedure fo
8、r verifying or certify-ing the equipment for this test method.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 b
9、eexactly equivalent.1.8 This standard does not purport to address 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
10、 use.2. Referenced Documents2.1 ASTM Standards:2D1250 Guide for Petroleum Measurement Tables (APIMPMS Chapter 11.1)D1265 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
11、 by Hydrometer Method (API MPMS Chapter 9.1)E1 Specification for ASTM Liquid-in-Glass ThermometersE100 Specification for ASTM Hydrometers2.2 API Standards:3MPMS Chapter 9.1 Test Method for Density, Relative Den-sity, and API Gravity of Crude Petroleum and LiquidPetroleum Products by Hydrometer Metho
12、d (ASTMD1298)MPMS Chapter 11.1-2004 including Addendum1-2007 Temperature and Pressure Volume CorrectionFactors for Generalized Crude Oils, Refined Products andLubricating OilsMPMS Chapter 11.2.2 Compressibility Factors for Hydro-carbons: 0.350-0.0637 Relative Density (60 F/60 F) and-50F to 140F Mete
13、ring TemperatureMPMS Chapter 11.2.2M Compressibility Factors for Hy-drocarbons: 350-637 Kilograms per Cubic Meter Density1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and the API Committee on Petroleum Measure-ment, and is the direct responsibi
14、lity of Subcommittee D02.02 /COMQ, the jointASTM-API Committee on Hydrocarbon Measurement for Custody Transfer (JointASTM-API).Current edition approved June 1, 2012. Published August 2012. Originallyapproved in 1939. Last previous edition approved in 2007 as D165702(2007).DOI: 10.1520/D1657-12.2For
15、referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American Petroleum Institute (API), 1220 L. St., N
16、W, Wash-ington, DC 20005-4070, http:/www.api.org.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.15C and -46 C to 60C Metering TemperaturesMPMS Chapter 11.2.4 Temperat
17、ure Correction for the Vol-ume of NGL and LPG Tables 23E, 24E, 53E, 54E, 59Eand 60E (joint standard with GPA TP-27)2.3 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
18、)2.4 ASTM Adjuncts: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 Discussi
19、onOther reference 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 ma
20、ss of an equal 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
21、glass hydrometer with aself-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
22、 is then placed 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
23、 reference tempera-ture by means of the volume correction factors or tables asapplicable by use of the appropriate adjunct to Guide D1250/API MPMS Chapter 11.1/GPA TP-27 and observed tempera-ture from the thermometer.5. Significance and Use5.1 The density or relative density of light hydrocarbons an
24、dliquefied 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 relative density with a range from0.500 to 0.650, and conforming to
25、 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. 101H or 310H.6.1.1.1 Thermohydrometers shall be of suitable ran
26、ge 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 ascertain that the instruments usedfor this procedure conform to
27、 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 certified and the appropriate corrections for themeniscus effect, the
28、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 recognized calibration certificate, are classed as uncertifiedand t
29、he 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 transparent plastic;for example, poly(methyl methacrylate) or eq
30、uivalent 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 metal end plates as shown inFig. 1.(WarningA protective shield sha
31、ll 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 read the hydrometer.Tests showed no attack by ethane, ethene (ethy
32、lene), 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,however, to clean the cylinder thoroughly after each determinat
33、ion.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 cleaning. (WarningExtremely flammable. Harmful ifinhaled. Vapors may
34、 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 giveboth 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 outle
35、t from the pressure cylinder.All valves shall be 6 mm (14 in.) or equivalent needle valves.4Available from Gas Processors Association (GPA), 6526 E. 60th St., Tulsa, OK74145, http:/www.gpaglobal.org.5Available from ASTM International Headquarters. Order Adjunct No.ADJD1250. Original adjunct produced
36、 in 1983.D1657 1226.2.2 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.NOTE 2For SafetyThe cylinder should be equipped with appropri-ate safety devices to prevent o
37、ver-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.FIG. 1 Pressure Hydrometer CylinderD1657 1236.3 Thermometers, conforming to ASTM 12C or 12F inSpecification E1. The therm
38、ometer 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 hydrometer cylinder with the test portionfully immersed below the test
39、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 required for stan-dardization of the hydrometer:7.1.1 Propane, pure g
40、rade, 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 Butane, pure grade, having a nominal density of584.1 kg/m3at 15C or a
41、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 hydrocar-bons shall be obtained by the procedures described in PracticeD
42、1265. 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 representativesample can be introduced into the cylinder.Ascertain that
43、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 vent valve at the top of thecylinder.8.1.2 When the connections have
44、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 which it shall be closed. At no time shall thepressure in the cylinde
45、r 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 the pressureinside the cylinder to be returned to atmospheric pressu
46、re.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, repeat thepurging to cool the cylinder sufficiently to permit its be
47、ingfilled 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 Apparatus9.1 Carefully clean and dry the hydrometer and the insid
48、ewall 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
49、 (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 within 0.2C of the test temperature until thermalequilibrium has been obtained. To accelerate thermal adjust-ment, occasionally remove the hydrometer cylinder from theconstant-temperature bath, tilt to a horizontal position, rockgently a few times to ensure mixing, and replace in theconstant-temperature bath. Exercise care to prevent damage tothe hydrometer and thermometer.9.
