ASTM D1298-1999(2005) Standard Test Method for Density Relative Density (Specific Gravity) or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method《比重计法.pdf

1、Designation: D 1298 99 (Reapproved 2005)Designation: Manual of Petroleum Measurement Standards (MPMS), Chapter 9.1Designation: 160/99An American National StandardStandard Test Method forDensity, Relative Density (Specific Gravity), or API Gravityof Crude Petroleum and Liquid Petroleum Products byHyd

2、rometer Method1This standard is issued under the fixed designation D 1298; the 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 epsil

3、on (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope1.1 This test method covers the laboratory determinationusing a glass hydrometer, of the density, relative density(specific gravity), or

4、API gravity of crude petroleum, petroleumproducts, or mixtures of petroleum and nonpetroleum productsnormally handled as liquids, and having a Reid vapor pressureof 101.325 kPa (14.696 psi) or less.1.2 Values are measured on a hydrometer at either thereference temperature or at another convenient te

5、mperature,and readings corrected to the reference temperature by meansof the Petroleum Measurement Tables; values obtained at otherthan the reference temperature being hydrometer readings andnot density measurements.1.3 Values determined as density, relative density, or APIgravity can be converted t

6、o equivalent values in the other unitsat alternate reference temperatures by means of the PetroleumMeasurement Tables.1.4 Annex A1 contains a procedure for verifying or certify-ing the equipment for this test method.1.5 This standard does not purport to address all of thesafety concerns, if any, ass

7、ociated 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:2D 97 Test Method for Pour Point of Petroleum ProductsD 3

8、23 Test Method for Vapor Pressure of Petroleum Prod-ucts (Reid Method)D 1250 Guide for Use of the Petroleum MeasurementTablesD 2500 Test Method for Cloud Point of Petroleum OilsD 3117 Test Method for WaxAppearance Point of DistillateFuelsD 4057 Practice for Manual Sampling of Petroleum andPetroleum

9、Products (API MPMS Chapter 8.1)D 4177 Practice for Automatic Sampling of Petroleum andPetroleum Products (API MPMS Chapter 8.2)D 5854 Practice for Mixing and Handling of LiquidSamples of Petroleum and Petroleum Products (APIMPMS Chapter 8.3)E1 Specification for ASTM Liquid-in-Glass ThermometersE 100

10、 Specification for ASTM Hydrometers2.2 API Standards:3MPMS Chapter 8.1 Manual Sampling of Petroleum andPetroleum Products (ASTM Practice D 4057)MPMS Chapter 8.2 Automatic Sampling of Petroleum andPetroleum Products (ASTM Practice D 4177)1This test method is under the jurisdiction of ASTM Committee D

11、02 onPetroleum Products and Lubricants and the API Committee on Petroleum Measure-ment, and is the direct responsibility of D02.02 /COMQ, the joint ASTM-APICommittee on Static Petroleum Measurement.Current edition approved Nov. 1, 2005. Published December 2005. Originallyapproved in 1953. Last previ

12、ous edition approved in 1999 as D 129899e2.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Published as Manu

13、al of Petroleum Measurement Standards. Available from theAmerican Petroleum Institute (API), 1220 L St., NW, Washington, DC 20005.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.MPMS Chapter 8.3 Mixing and Handling of Liquid Sampleso

14、f Petroleum and Petroleum Products (ASTM PracticeD 5854)2.3 Institute of Petroleum Standards:4IP 389 Determination of wax appearance temperature(WAT) of middle distillate fuels by differential thermalanalysis (DTA) or differential scanning calorimetry (DSC)IPStandard Methods Book, AppendixA, Specifi

15、cations IPStandard Thermometers2.4 ISO Standards:5ISO 649-1 Laboratory glassware Density hydrometers forgeneral purpose Part 1: Specification3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 API gravity, na special function of relative density(specific gravity) 60/60F, represent

16、ed by: API 5 141.5/sp gr 60/60F!2131.5 (1)3.1.1.1 DiscussionNo statement of reference temperatureis required, as 60F is included in the definition.3.1.2 cloud point, ntemperature at which a cloud of waxcrystals first appears in a liquid when it is cooled under specificconditions.3.1.3 density, nthe

17、mass of liquid per unit volume at 15Cand 101.325 kPa with the standard unit of measurement beingkilograms per cubic metre.3.1.3.1 DiscussionOther reference temperatures, such as20C, may be used for some products or in some locations.Less preferred units of measurement (for example, kg/L org/mL) are

18、still in use.3.1.4 observed values, nvalues observed at temperaturesother than the specified reference temperature. These values areonly hydrometer readings and not density, relative density(specific gravity), or API gravity at that other temperature.3.1.5 pour point, nlowest temperature at which a

19、testportion of crude petroleum or petroleum product will continueto flow when it is cooled under specified conditions.3.1.6 relative density (specific gravity), nthe ratio of themass of a given volume of liquid at a specific temperature tothe mass of an equal volume of pure water at the same ordiffe

20、rent temperature. Both reference temperatures shall beexplicitly stated.3.1.6.1 DiscussionCommon reference temperatures in-clude 60/60F, 20/20C, 20/4C. The historic deprecated termspecific gravity may still be found.3.1.7 wax appearance temperature (WAT), ntemperatureat which waxy solids form when a

21、 crude petroleum orpetroleum product is cooled under specified conditions.4. Summary of Test Method4.1 The sample is brought to a specified temperature and atest portion is transferred to a hydrometer cylinder that hasbeen brought to approximately the same temperature. Theappropriate hydrometer, als

22、o at a similar temperature, islowered into the test portion and allowed to settle. Aftertemperature equilibrium has been reached, the hydrometerscale is read, and the temperature of the test portion is taken.The observed hydrometer reading is reduced to the referencetemperature by means of the Petro

23、leum Measurement Tables. Ifnecessary, the hydrometer cylinder and its contents are placedin a constant temperature bath to avoid excessive temperaturevariation during the test.5. Significance and Use5.1 Accurate determination of the density, relative density(specific gravity), or API gravity of petr

24、oleum and its productsis necessary for the conversion of measured volumes tovolumes or masses, or both, at the standard reference tempera-tures during custody transfer.5.2 This test method is most suitable for determining thedensity, relative density (specific gravity), or API gravity oflow viscosit

25、y transparent liquids. This test method can also beused for viscous liquids by allowing sufficient time for thehydrometer to reach equilibrium, and for opaque liquids byemploying a suitable meniscus correction.5.3 When used in connection with bulk oil measurements,volume correction errors are minimi

26、zed by observing thehydrometer reading at a temperature close to that of the bulk oiltemperature.5.4 Density, relative density (specific gravity), or API grav-ity is a factor governing the quality and pricing of crudepetroleum. However, this property of petroleum is an uncertainindication of its qua

27、lity unless correlated with other properties.5.5 Density is an important quality indicator for automotive,aviation and marine fuels, where it affects storage, handlingand combustion.6. Apparatus6.1 Hydrometers, of glass, graduated in units of density,relative density, or API gravity as required, con

28、forming toSpecification E 100 or ISO 649-1, and the requirements givenin Table 1.6.1.1 The user should ascertain that the instruments used forthis test conform to the requirements set out above with respectto materials, dimensions, and scale errors. In cases where theinstrument is provided with a ca

29、libration certificate issued by arecognized standardizing body, the instrument is classed ascertified and the appropriate corrections listed shall be applied4Available from Energy Institute, 61 New Cavendish St., London, W1M 8AR,UK.5Available from American National Standards Institute (ANSI), 25 W.

30、43rd St.,4th Floor, New York, NY 10036.TABLE 1 Recommended HydrometersUnits Range ScaleAMeniscusTotalEachUnitIntervalAErrorACorrectionDensity, kg/m3at 15C 600 - 1100600 - 1100600 - 11002050500.20.51.06 0.26 0.36 0.6+0.3+0.7+1.4Relative density (specificgravity) 60/60F0.600 - 1.1000.600 - 1.1000.600

31、- 1.1000.0200.0500.0500.00020.00050.0016 0.00026 0.00036 0.0006+0.0003+0.0007+0.0014Relative density (specificgravity), 60/60F 0.650 - 1.100 0.050 0.0005 60.0005API 1 - +101 12 0.1 6 0.1AInterval and Error relate to Scale.D 1298 99 (2005)2to the observed readings. Instruments that satisfy the requir

32、e-ments of this test method, but are not provided with arecognized calibration certificate, are classed as uncertified.6.2 Thermometers, having range, graduation intervals andmaximum permitted scale error shown in Table 2 and conform-ing to Specification E1or IP Appendix A.6.2.1 Alternate measuring

33、devices or systems may be used,provided that the total uncertainty of the calibrated system is nogreater than when using liquid-in-glass thermometers.6.3 Hydrometer Cylinder, clear glass, plastic (see 6.3.1), ormetal. The inside diameter of the cylinder shall be at least25 mm greater than the outsid

34、e diameter of the hydrometer andthe height shall be such that the appropriate hydrometer floatsin the test portion with at least 25 mm clearance between thebottom of the hydrometer and the bottom of the cylinder.6.3.1 Hydrometer cylinders constructed of plastic materialsshall be resistant to discolo

35、ration or attack by oil samples andshall not affect the material being tested. They shall not becomeopaque under prolonged exposure to sunlight.6.4 Constant-Temperature Bath, if required, of dimensionssuch that it can accommodate the hydrometer cylinder with thetest portion fully immersed below the

36、test portion liquidsurface, and a temperature control system capable of maintain-ing the bath temperature within 0.25C of the test temperaturethroughout the duration of the test.6.5 Stirring Rod, optional, of glass or plastic, approximately400 mm in length.7. Sampling7.1 Unless otherwise specified,

37、samples of non-volatilepetroleum and petroleum products shall be taken by theprocedures described in Practices D 4057 (API MPMS Chapter8.1) and D 4177 (API MPMS Chapter 8.2).7.2 Samples of volatile crude petroleum or petroleum prod-ucts are preferably taken by Practice D 4177 (API MPMSChapter 8.2),

38、using a variable volume (floating piston) samplereceiver to minimize any loss of light components which mayaffect the accuracy of the density measurement. In the absenceof this facility, extreme care shall be taken to minimize theselosses, including the transfer of the sample to a chilledcontainer i

39、mmediately after sampling.7.3 Sample MixingMay be necessary to obtain a testportion representative of the bulk sample to be tested, butprecautions shall be taken to maintain the integrity of thesample during this operation. Mixing of volatile crude petro-leum or petroleum products containing water o

40、r sediments, orboth, or the heating of waxy volatile crude petroleum orpetroleum products may result in the loss of light components.The following sections (7.3.1 to 7.3.4) will give some guidanceon sample integrity maintenance.7.3.1 Volatile Crude Petroleum and Petroleum ProductsHaving an RVP Great

41、er than 50 kPaMix the sample in itsoriginal closed container in order to minimize the loss of lightcomponents.NOTE 1Mixing volatile samples in open containers will lead to loss oflight components and consequently affect the value of the densityobtained.7.3.2 Waxy Crude PetroleumIf the petroleum has

42、a pourpoint above 10C, or a cloud point or WAT above 15C, warmthe sample to 9C above the pour point, or 3C above the cloudpoint or WAT, prior to mixing. Whenever possible, mix thesample in its original closed container in order to minimize theloss of light components.7.3.3 Waxy DistillateWarm the sa

43、mple to 3C above itscloud point or WAT prior to mixing.7.3.4 Residual Fuel OilsHeat the sample to the testtemperature prior to mixing (see 8.1.1 and Note 4).7.4 Additional information on the mixing and handling ofliquid samples will be found in Practice D 5854 (API MPMSChapter 8.3).8. Procedure8.1 T

44、emperature of Test:8.1.1 Bring the sample to the test temperature which shall besuch that the sample is sufficiently fluid but not so high as tocause the loss of light components, nor so low as to result in theappearance of wax in the test portion.NOTE 2The density, relative density orAPI gravity de

45、termined by thehydrometer is most accurate at or near the reference temperature.NOTE 3The volume and density, the relative density, and the APIcorrections in the Petroleum Measurement Tables are based on the averageexpansions of a number of typical materials. Since the same coefficientswere used in

46、compiling each set of tables, corrections made over the sametemperature interval minimize errors arising from possible differencesbetween the coefficient of the material under test and the standardcoefficients. This effect becomes more important as temperatures divergefrom the reference temperature.

47、NOTE 4The hydrometer reading is obtained at a temperature appro-priate to the physico-chemical characteristics of the material under test.This temperature is preferably close to the reference temperature, or whenthe value is used in conjunction with bulk oil measurements, within 3Cof the bulk temper

48、ature (see 5.3).8.1.2 For crude petroleum, bring the sample close to thereference temperature or, if wax is present, to 9C above itspour point or 3C above its cloud point or WAT, whichever ishigher.NOTE 5For crude petroleum an indication of the WAT can be foundusing IP 389, with the modification of

49、using 50 L 6 5 L of sample. Theprecision of WAT for crude petroleum using this technique has not beendetermined.9. Apparatus Verification or Certification9.1 Hydrometers and thermometers shall be verified inaccordance with the procedures in Annex A1.10. Procedure10.1 Bring the hydrometer cylinder and thermometer towithin approximately 5C of the test temperature.10.2 Transfer the sample to the clean, temperature-stabilized hydrometer cylinder without splashing, to avoid theTABLE 2 Recommended ThermometersScale Range Graduation Interva