ASTM D1657-2002(2007) Standard Test Method for Density or Relative Density of Light Hydrocarbons by Pressure Hydrometer《用压力液体比重计测定轻烃类物质的密度或相对密度的标准试验方法》.pdf

1、Designation: D 1657 02 (Reapproved 2007)Designation: Manual of Petroleum Measurement Standards (MPMS), Chapter 9.2An American National StandardStandard Test Method forDensity or Relative Density of Light Hydrocarbons byPressure Hydrometer1This standard is issued under the fixed designation D 1657; t

2、he number immediately following the designation 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 (e) indicates an editorial change since the last revision or reapproval.1

3、. Scope1.1 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 mate-rials having vapor pressures hi

4、gher than 1.4 MPa (200 psi) atthe test temperature. This pressure limit is dictated by the typeof equipment. Higher pressures may apply to other equipmentdesigns.1.3 The values in SI units are to be regarded as the standard.The values in parentheses are for information only. Both SI andcustomary uni

5、ts have been rounded so that they may not beexactly equivalent.1.4 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 applic

6、a-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 1250 Guide for Use of the Petroleum MeasurementTablesD 1265 Practice for Sampling Liquefied Petroleum (LP)Gases, Manual MethodE1 Specification for ASTM Liquid-in-Glass ThermometersE 100 Specification for AST

7、M Hydrometers2.2 ASTM Adjuncts:Adjunct to D 1250 Guide for Petroleum Measurement Tables(API MPMS Chapter 11.1)3. 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.

8、1.1 DiscussionOther 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 temperat

9、ure tothe mass 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 thermohyd

10、rometer, na 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

11、the cylinder is then placed in aconstant-temperature bath. When the temperature has reachedequilibrium, the hydrometer reading and the temperature of thesample are noted.5. Significance and Use5.1 The density or relative density of light hydrocarbons andliquefied petroleum gases is used in custody t

12、ransfer quantitycalculations or to satisfy transportation, storage, and regulatoryrequirements.1This 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 responsibility of Subcommittee D02.0

13、2.0A /COMQ, the jointASTM-API Committee on Temperature, Density, Physical Properties.Current edition approved May 1, 2007. Published June 2007. Originallyapproved in 1939. Last previous edition approved in 2002 as D 1657 02.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcont

14、act ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6. Apparatus6.1 Hydrom

15、eters, 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 the dimensions in Specifi-cation E 100.6.1.1 Thermohydrometers, for field applications, thermohy-drometers may be more convenient than hydrometers withseparate the

16、rmometers. They shall conform to SpecificationE 100, Thermohydrometer Nos. 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 r

17、eport shall state that a thermohydrometerwas used.6.2 Hydrometer Cylinder, constructed of 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

18、shall float freely within it. The ends shall be tightlysealed with neoprene gaskets and metal 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 pl

19、astics and cloud the inner surfaceof the cylinder, making it difficult or impossible to read the hydrometer.Tests showed no attack by ethane, ethene (ethylene), propane, propylene,butane, methylpropane (isobutane), butenes (normal butylenes), methyl-propene (isobutylene), pentane, and methylbutane (

20、isopentane), and noattack is expected from butadiene and acetaldehyde. Users are cautioned,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 plas

21、ticsand should similarly not be used. A light aliphatic hydrocarbon isrecommended for cleaning. (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 giveb

22、oth 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 the 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 pres

23、suregreater 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.6.3 Thermometers, 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

24、 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 portion liquid surface, and atemperature control system capable of maintaining the bathte

25、mperature 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 grade, having a nominal density of507.6 kg/m3at 15C or a relative density 60/60F of 0.5069

26、9.(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 relative density 60/60F of 0.5840.(WarningExtremely flammable. Harmful if inhaled. Vapors

27、may 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 1265. The procedure for sampling for verification of theapparatus and for subsequent tes

28、ting 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 theseconnections are free of leaks. Open the outlet and vent valvesand purge the samplin

29、g 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 been purged, close theoutlet and vent valves and open the inlet valve, permitting theliq

30、uid to enter the cylinder until it is full. If necessary, the ventvalve can be opened slightly to permit complete filling of thecylinder after which 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 h

31、as 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 pressure.8.1.4 Close the outlet and vent valves and open the inletvalve, filling the cylinder

32、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 beingfilled without venting.8.1.5 With all valves closed, examine the apparatus forleaks.

33、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 insidewall of the pressure cylinder.9.2 Insert the hydrometer in the pressure cylinder and at

34、tachthe 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.D 1657 02 (2007)29.3 Disconnect th

35、e 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

36、 bath, tilt to a horizontal position, rockFIG. 1 Pressure Hydrometer CylinderD 1657 02 (2007)3gently a few times to ensure mixing, and replace in theconstant-temperature bath. Exercise care to prevent damage tothe hydrometer and thermometer.9.4 When the hydrometer cylinder and thermometer havereache

37、d equilibrium, as shown by the thermometer inside thecylinder, remove the cylinder from the constant-temperaturebath, stand it on a firm level surface, and while the hydrometeris floating freely, take the hydrometer reading promptly asdescribed in 9.4.1 and 9.4.2.9.4.1 Observe a point slightly below

38、 the plane of the liquidsurface and then raise the line of vision until this surface, seenas an ellipse, becomes a straight line. Record the point wherethis line cuts the hydrometer scale, estimating to the nearestone fifth of a scale division the observed hydrometer reading.A white card held behind

39、 the cylinder just below the liquidlevel will improve the visibility of the surface.9.4.2 Read and record the temperature of the liquid to thenearest 0.2C, immediately before and after reading the hy-drometer. If the temperature differs by more than 0.4C,replace the hydrometer cylinder in the bath t

40、o restore equilib-rium and repeat the readings.9.5 Repeat the verification with a second portion of thesame reference fluid.9.6 If the temperatures measured in 9.4.2 are within 0.2Cof the reference temperature and the two determinations arewithin 0.7 kg/m3or 0.0007 relative density, average the twod

41、eterminations. If the temperatures are not within 0.2C of thereference temperature, correct the observed hydrometer read-ings to the reference temperature by use of the appropriatevolume of the Petroleum Measurement Tables (Adjunct toGuide D 1250/API MPMS Chapter 11.1). Repeat the verifica-tion with

42、 two additional determinations.9.7 Compare the average results with the known density ofthe reference fluids used (see 9.2).9.7.1 If the results are within 0.2 kg/m3(0.0002 relativedensity), accept the hydrometer scale as suitable for directreading.9.7.2 If the difference is between 0.2 and 1.0 kg/m

43、3(0.0002and 0.001 relative density) from the known value, apply thiscorrection to readings obtained on test portions of samples.9.7.3 If the readings differ more than 1.0 kg/m3(0.001relative density) from the known value, replace the hydrometer.9.8 After each determination, empty the cylinder and ve

44、nt toreduce the pressure to atmospheric in a safe place. Highlyvolatile liquids and liquefied petroleum gases shall not be leftin the apparatus because, at high ambient temperatures, theymight generate sufficient pressure to burst the cylinder.10. Procedure10.1 Purge and empty the apparatus and draw

45、 a sample ofthe product to be tested as in Section 8.10.2 Carry out the procedures and take the reading asdescribed in Section 9. After each determination, empty thecylinder and vent to reduce the pressure to atmospheric in asafe place.NOTE 2For measurements in the field, this method may be used ata

46、mbient temperatures, with the realization that the accuracy is decreased.(WarningIf so used, the cylinder must be vented and the test discardedif the pressure rises above a gauge pressure of 1.4 MPa (200 psi).)11. Calculation and Report11.1 Apply hydrometer corrections, if any, to the observedreadin

47、gs and report the corrected reading to the nearest0.5 kg/m3or 0.0005 relative density.11.2 If the determinations were not carried out within 0.2Cof the reference temperature, correct the results by use of theappropriate volume of the Petroleum Measurement Tables(Adjunct to Guide D 1250/API MPMS Chap

48、ter 11.1).11.2.1 When a density-scaled hydrometer was used, useTable 53 for densities up to 612 kg/m3and Table 53A fordensities above that to obtain density at 15C.11.2.2 When a relative density hydrometer was used, useTable 23 for relative densities up to 0.655 and Table 23A forrelative densities a

49、bove that to obtain relative density at 15C.11.3 Report the final result as density to the nearest0.5 kg/m3at 15C or as relative density to the nearest 0.0005and specify the reference temperature.11.3.1 The test report shall contain at least the followinginformation:11.3.1.1 A reference to this standard.11.3.1.2 The type and complete identification of the producttested.11.3.1.3 The result of the test.11.3.1.4 The date of the test.11.3.1.5 Any deviations from the test method.11.3.1.6 State whether a thermohydrometer was used.12. Precision and Bias12.1