ASTM D1298-2012a Standard Test Method for Density Relative Density (Specific Gravity) or API Gravity of Crude Petroleum and Liquid Petroleum Products by Hydrometer Method.pdf

1、Designation: D1298 12aDesignation: 160/99API Designation: Manual of Petroleum Measurement Standards (MPMS), Chapter 9.1Standard Test Method forDensity, Relative Density (Specific Gravity), or API Gravityof Crude Petroleum and Liquid Petroleum Products byHydrometer Method1This standard is issued unde

2、r the fixed designation D1298; 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 epsilon () indicates an editorial change since th

3、e last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This test method covers the laboratory determinationusing a glass hydrometer in conjunction with a series ofcalculations, of the density, relative density, or API gravity ofcru

4、de petroleum, petroleum products, or mixtures of petroleumand nonpetroleum products normally handled as liquids, andhaving a Reid vapor pressure of 101.325 kPa (14.696 psi) orless. Values are determined at existing temperatures andcorrected to 15C or 60F by means of a series of calculationsand inter

5、national standard tables.1.2 The initial hydrometer readings obtained are uncor-rected hydrometer readings and not density measurements.Readings are measured on a hydrometer at either the referencetemperature or at another convenient temperature, and readingsare corrected for the meniscus effect, th

6、e thermal glass expan-sion effect, alternate calibration temperature effects and to thereference temperature by means of the Petroleum MeasurementTables; values obtained at other than the reference temperaturebeing hydrometer readings and not density measurements.1.3 Readings determined as density,

7、relative density, or APIgravity can be converted to equivalent values in the other unitsor alternate reference temperatures by means of Interconver-sion Procedures, or Adjunct to D1250 Guide for PetroleumMeasurement Tables (API MPMS Chapter 11.1), or both, ortables, as applicable.1.4 The initial hyd

8、rometer readings determined in the labo-ratory shall be recorded before performing any calculations.The calculations required in Section 10 shall be applied to theinitial hydrometer reading with observations and results re-ported as required by Section 11 prior to use in a subsequentcalculation proc

9、edure (ticket calculation, meter factor calcula-tion, or base prover volume determination).1.5 Annex A1 contains a procedure for verifying or certify-ing the equipment for this test method.1.6 The values stated in SI units are to be regarded asstandard. The values given in parentheses are provided f

10、orinformation only.1.7 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

11、use.2. Referenced Documents2.1 ASTM Standards:2D1250 Guide for Use of the Petroleum Measurement TablesD4057 Practice for Manual Sampling of Petroleum andPetroleum Products (API MPMS Chapter 8.1)D4177 Practice for Automatic Sampling of Petroleum andPetroleum Products (API MPMS Chapter 8.2)D5854 Pract

12、ice for Mixing and Handling of Liquid Samplesof Petroleum and Petroleum Products (API MPMS Chapter8.3)E1 Specification for ASTM Liquid-in-Glass ThermometersE100 Specification for ASTM Hydrometers2.2 API Standards:3MPMS Chapter 8.1 Manual Sampling of Petroleum andPetroleum Products (ASTM Practice D40

13、57)MPMS Chapter 8.2 Automatic Sampling of Petroleum andPetroleum Products (ASTM Practice D4177)MPMS Chapter 8.3 Mixing and Handling of Liquid Samples1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and the API Committee on Petroleum Measure-ment,

14、and is the direct responsibility of D02.02 /COMQ on Hydrocarbon Measure-ment for Custody Transfer (Joint ASTM-API).Current edition approved May 15, 2012. Published October 2012. Originallyapproved in 1953. Last previous edition approved in 2012 as D129812. DOI:10.1520/D1298-12A.2For referenced ASTM

15、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 Manual of Petroleum Measurement Standards. Available from theAmerica

16、n Petroleum Institute (API), 1220 L St., NW, Washington, DC 20005.1*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.of Petroleum and Petroleum Products (ASTM PracticeD58

17、54)MPMS Chapter 11.1-2004 including Addendum1-2007 Temperature and Pressure Volume CorrectionFactors for Generalized Crude Oils, Refined Products andLubricating Oilsi2.3 Energy Institute Standards:4IP 389 Determination of wax appearance temperature(WAT) of middle distillate fuels by differential the

18、rmalanalysis (DTA) or differential scanning calorimetry (DSC)IPStandard Methods Book, AppendixA, Specifications IPStandard Thermometers2.4 ISO Standards:5ISO 649-1 Laboratory glassware Density hydrometers forgeneral purpose Part 1: Specification2.5 ASTM Adjuncts:Adjunct to D1250 Guide for Petroleum

19、Measurement Tables(API MPMS Chapter 11.1)63. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 API gravity, na special function of relative density(specific gravity) 60/60F, represented by: API 5 141.5/relative density 60/60F!2131.5 (1)3.1.1.1 DiscussionNo statement of reference te

20、mperatureis 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 mass of liquid per unit volume at 15Cand 101.325 kPa with the standard unit of measureme

21、nt 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 still in use.3.1.4 observed values, nvalues observed at temperaturesother than the speci

22、fied 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 testportion of crude petroleum or petroleum product will continueto flow when it is cool

23、ed 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 ordifferent temperature. Both reference temperatures shall beexplicitly stated.3.1.6.1 Discussi

24、onCommon 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 crude petroleum orpetroleum product is cooled under specified conditions.4. Summary of

25、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 and thermometer, also at a similartemperature, are lowered into the test portion and allowed

26、 tosettle. After temperature equilibrium has been reached, thehydrometer scale is read, and the temperature of the testportion is taken. The observed hydrometer reading is correctedfor the meniscus effect, the thermal glass expansion effect,alternate calibration temperature effects and then reduced

27、to thereference temperature by means of the volume correctionfactors or tables as applicable by use of the appropriateAdjunctto D1250 Guide for Petroleum Measurement Tables (APIMPMS Chapter 11.1) and observed temperature from thethermometer.4.2 If necessary, the hydrometer cylinder and its contentsa

28、re placed in a constant temperature bath to avoid excessivetemperature variation during the test.5. Significance and Use5.1 Accurate determination of the density, relative density(specific gravity), or API gravity of petroleum and its productsis necessary for the conversion of measured volumes tovol

29、umes or masses, or both, at the standard reference tempera-tures of 15C or 60F during custody transfer.5.2 This procedure is most suitable for determining thedensity, relative density (specific gravity), or API gravity oflow viscosity transparent liquids. This procedure can also beused for viscous l

30、iquids by allowing sufficient time for thehydrometer to reach temperature equilibrium, and for opaqueliquids by employing a suitable meniscus correction. Addition-ally for both transparent and opaque fluids the readings shall becorrected for the thermal glass expansion effect and alternatecalibratio

31、n temperature effects before correcting to the refer-ence temperature.5.3 When used in connection with bulk oil measurements,volume correction errors are minimized by observing thehydrometer reading at a temperature close to that of the bulk oiltemperature.5.4 Density, relative density, or API gravi

32、ty is a factorgoverning the quality and pricing of crude petroleum. How-ever, this property of petroleum is an uncertain indication of itsquality unless correlated with other properties.5.5 Density is an important quality indicator for automotive,aviation and marine fuels, where it affects storage,

33、handlingand combustion.6. Apparatus6.1 Hydrometers, of glass, graduated in units of density,relative density, or API gravity as required, conforming toSpecification E100 or ISO 649-1, and the requirements givenin Table 1.6.1.1 The user should ascertain that the instruments used forthis procedure con

34、form to the requirements set out above with4Available from Energy Institute, 61 New Cavendish St., London, W1M 8AR,UK.5Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.6Available from ASTM International Headquarters. Order Adjunct No.ADJD1250.

35、 Original adjunct produced in 1983.D1298 12a2respect 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 eff

36、ect, 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 recognized calibration certificate, are classed as uncerti

37、fied.6.2 Thermometers, having range, graduation intervals andmaximum permitted scale error shown in Table 2 and conform-ing to Specification E1 or IP Appendix A.6.2.1 Alternate measuring devices or systems may be used,provided that the total uncertainty of the calibrated system is nogreater than tha

38、t specified in 6.2. The stated repeatability andreproducibility values are not applicable if alternate fluids areused in the liquid-in-glass thermometers.6.3 Hydrometer Cylinder, clear glass, or plastic (see 6.3.1).The inside diameter of the cylinder shall be at least 25 mmgreater than the outside d

39、iameter of the hydrometer and theheight shall be such that the appropriate hydrometer floats inthe sample test portion with at least 25 mm clearance betweenthe bottom of the hydrometer and the bottom of the cylinder.6.3.1 Hydrometer cylinders constructed of plastic materialsshall be resistant to dis

40、coloration 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

41、the 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 specifi

42、ed, samples of non-volatilepetroleum and petroleum products shall be taken by theprocedures described in Practice D4057 (API MPMS Chapter8.1) and D4177 (API MPMS Chapter 8.2).7.2 Samples of volatile crude petroleum or petroleum prod-ucts are preferably taken by Practice D4177 (API MPMSChapter 8.2),

43、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

44、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

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

46、eater 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 h

47、as anexpected pour point above 10C, or a cloud point or WATabove 15C, warm the sample to a temperature that is sufficientfor ensuring the material is fluid enough to provide adequatemixing without excessively heating the material that wouldotherwise compromise the integrity of the sample. Sampleshea

48、ted to 9C above its pour point, or 3C above its cloud pointor WAT have been found to be suitable temperatures to warmsamples prior to mixing. Whenever possible, mix the sample inits original closed container in order to minimize the loss oflight components.7.3.3 Waxy DistillateWarm the sample to a t

49、emperaturethat is sufficient for ensuring the material is fluid enough toprovide adequate mixing without excessively heating thematerial that would otherwise compromise the integrity of thesample. Samples heated to 3C above its cloud point or WAThave been found to be suitable temperatures to warm samplesprior to mixing.7.3.4 Residual Fuel OilsHeat the sample to the testtemperature prior to mixing (see 9.1.1 and Note 4).7.4 Additional information on the mixing and handling ofliquid samples will be found in Practice D5854 (API MPMSChapter 8.3)