ASTM D6822-12b(2017) Standard Test Method for Density, Relative Density, and API Gravity of Crude Petroleum and Liquid Petroleum Products by Thermohydrometer Method.pdf

1、Designation: D6822 12b (Reapproved 2017)Manual of Petroleum Measurement Standards (MPMS), Chapter 9.3Standard Test Method forDensity, Relative Density, and API Gravity of CrudePetroleum and Liquid Petroleum Products byThermohydrometer Method1This standard is issued under the fixed designation D6822;

2、 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 the last revision or reapproval.

3、1. Scope1.1 This test method covers the determination, using a glassthermohydrometer in conjunction with a series of calculations,of the density, relative density, or API gravity of crudepetroleum, petroleum products, or mixtures of petroleum andnonpetroleum products normally handled as liquids and

4、havinga Reid vapor pressures of 101.325 kPa (14.696 psi) or less.Values are determined at existing temperatures and corrected to15 C or 60 F by means of a series of calculations andinternational standard tables.1.2 The initial thermohydrometer readings obtained areuncorrected hydrometer readings and

5、 not density measure-ments. Readings are measured on a thermohydrometer at eitherthe reference temperature or at another convenienttemperature, and readings are corrected for the meniscus effect,the thermal glass expansion effect, alternate calibration tem-perature effects and to the reference tempe

6、rature by means ofcalculations and Adjunct to D1250 Guide for Use of thePetroleum Measurement Tables (API MPMS Chapter 11.1).1.3 Readings determined as density, relative density, or APIgravity can be converted to equivalent values in the other unitsor alternate reference temperatures by means of Int

7、erconver-sion Procedures (API MPMS Chapter 11.5) or Adjunct toD1250 Guide for Use of the Petroleum Measurement Tables(API MPMS Chapter 11.1), or both, or tables as applicable.1.4 The initial thermohydrometer reading shall be recordedbefore performing any calculations. The calculations requiredin Sec

8、tion 9 shall be applied to the initial thermohydrometerreading with observations and results reported as required bySection 11 prior to use in a subsequent calculation procedure(measurement ticket calculation, meter factor calculation, orbase prover volume determination).1.5 Annex A1 contains a proc

9、edure for verifying or certify-ing the equipment of this test method.1.6 The values stated in SI units are to be regarded asstandard.1.6.1 ExceptionThe values given in parentheses are forinformation only.1.7 This standard does not purport to address all of thesafety concerns, if any, associated with

10、 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.1.8 This international standard was developed in accor-dance with internationally recognized principles on stan

11、dard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1250 Guide for Use of the Petroleum Measurem

12、ent TablesD1298 Test Method for Density, Relative Density, or APIGravity of Crude Petroleum and Liquid Petroleum Prod-ucts by Hydrometer MethodD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD5854 Practice f

13、or Mixing and Handling of Liquid Samples1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and the API Committee onPetroleum Measurement, and is the direct responsibility of Subcommittee D02.02/COMQ, the joint ASTM-API Committee on Hy

14、drocarbon Measurement forCustody Transfer (Joint ASTM-API). This test method has been approved by thesponsoring committees and accepted by the Cooperating Societies in accordancewith established procedures.Current edition approved July 15, 2017. Published July 2012. Originallyapproved in 2002. Last

15、previous edition approved in 2012 as D6822 12b. DOI:10.1520/D6822-12BR17.2For 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 A

16、STM website. Jointly copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, USA and the American Petroleum Institute (API), 1220 L Street NW, Washington DC 20005, USAThis international standard was developed in accordance with internationally recogni

17、zed principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1of Petroleum and Petroleum ProductsD6300 Practice for Determinatio

18、n of Precision and BiasData for Use in Test Methods for Petroleum Products andLubricantsE100 Specification for ASTM Hydrometers2.2 API Standards:3MPMS Chapter 8.1 Practice for Manual Sampling of Petro-leum and Petroleum Products (ASTM Practice D4057)MPMS Chapter 8.2 Practice for Automatic Sampling o

19、fPetroleum and Petroleum Products (ASTM PracticeD4177)MPMSChapter 8.3 Practice for Mixing and Handling ofLiquid Samples of Petroleum and Petroleum Products(ASTM Practice D5854)MPMS Chapter 9.1 Hydrometer Test Method for Density,Relative Density or API Gravity of Crude Petroleum andLiquid Petroleum P

20、roducts (ASTM Test Method D1298)MPMS Chapter 11.1 Temperature and Pressure Volume Cor-rection Factors for Generalized Crude Oils, RefinedProducts, and Lubricating Oils (Adjunct toASTM D1250)MPMS Chapter 11.5 Density/Weight/Volume Intraconver-sion2.3 ASTM Adjuncts:Adjunct to D1250 Guide for Use of th

21、e Petroleum Measure-ment Tables (API MPMS Chapter 11.1)43. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 API gravity (API), na special function of relativedensity 60/60 F, represented by:API 5 141.5/relative density 60/60F!# 2 131.5 (1)3.1.1.1 DiscussionNo statement of referenc

22、e temperatureis required, as 60 F is included in the definition.3.1.2 density, nthe mass of liquid per unit volume at 15 Cand 101.325 kPa with the standard unit of measurement beingkilograms per cubic metre (kg/m3).3.1.2.1 DiscussionOther reference temperatures, such as20 C, may be used for some pro

23、ducts or in some locations.Less preferred units of measurement, for example, kg/L org/mL, are still in use.3.1.3 hydrometer reading, nthe point on the hydrometerscale at which the surface of the liquid cuts the scale.3.1.3.1 DiscussionIn practice for transparent fluids thiscan be readily determined

24、by aligning the surface of the liquidon both sides of the hydrometer and reading the Hydrometerscale where these surface readings cut the scale (HydrometerReading Observed). For nontransparent fluids the point atwhich the liquid surface cuts the Hydrometer scale cannot bedetermined directly and requ

25、ires a correction (Meniscus Cor-rection). The value represented by the point (Meniscus Read-ing) at which the liquid sample rises above the main surface ofthe liquid subtracted from the value represented by where themain surface of the liquid cuts the Hydrometer scale is theamount of the correction

26、or Meniscus correction. This menis-cus correction is documented and then subtracted from thevalue represented by the Meniscus Reading to yield theHydrometer Reading corrected for the Meniscus (HydrometerReading Observed, Meniscus Corrected).3.1.4 observed values, nhydrometer readings observed ata te

27、mperature other than the defined reference temperature.3.1.4.1 DiscussionThese values are only hydrometer read-ings and not density, relative density, or API gravity at thetemperature.3.1.5 relative density, nthe ratio of the mass of a givenvolume of liquid at a specific temperature to the mass of a

28、nequal volume of pure water at the same or different tempera-ture. Both reference temperatures shall be explicitly stated.3.1.5.1 DiscussionCommon reference temperatures in-clude 15/15 C, 60 60 F, 20/20 C, and 20/4 C. The historicterm specific gravity may still be found.3.1.6 thermohydrometer, na gl

29、ass hydrometer with a self-contained thermometer.4. Summary of Test Method4.1 The density or API gravity, after temperature equilib-rium has been reached, is read by observing the freely floatingthermohydrometer and noting the graduation nearest to theapparent intersection of the horizontal plane su

30、rface of theliquid with the vertical scale of the hydrometer after tempera-ture equilibrium has been reached. The observed thermohy-drometer reading is reduced to the reference temperature valueby means of the Petroleum Measurement Tables (the appropri-ate adjunct to Adjunct to D1250 Guide for Petro

31、leum Mea-surement Tables (API MPMS Chapter 11.1) and observedtemperature from the enclosed thermometer.5. Significance and Use5.1 Density and API gravity are used in custody transferquantity calculations and to satisfy transportation, storage, andregulatory requirements. Accurate determination of de

32、nsity orAPI gravity of crude petroleum and liquid petroleum productsis necessary for the conversion of measured volumes tovolumes at the standard temperatures of 15 C or 60 F.5.2 Density andAPI gravity are also factors that indicate thequality of crude petroleum. Crude petroleum prices are fre-quent

33、ly posted against values in kg/m3or in degrees API.However, this property of petroleum is an uncertain indicationof its quality unless correlated with other properties.5.3 Field of ApplicationBecause the thermohydrometerincorporates both the hydrometer and thermometer in onedevice, it is more applic

34、able in field operations for determiningdensity or API gravity of crude petroleum and other liquidpetroleum products. The procedure is convenient for gatheringmain trunk pipelines and other field applications where limitedlaboratory facilities are available. The thermohydrometermethod may have limit

35、ations in some petroleum densitydeterminations. When this is the case, other methods such asTest Method D1298 (API MPMS Chapter 9.1) may be used.5.4 This procedure is suitable for determining the density,relative density, or API gravity of low viscosity, transparent or3Available from American Petrol

36、eum Institute (API), 1220 L. St., NW,Washington, DC 20005-4070, www.api.org.4Available from ASTM International Headquarters. Order Adjunct No.ADJD1250. Original adjunct produced in 1983.D6822 12b (2017)2opaque liquids, or both. This procedure, when used for opaqueliquids, requires the use of a menis

37、cus correction (see 9.2).Additionally for both transparent and opaque fluids the read-ings shall be corrected for the thermal glass expansion effectand alternate calibration temperature effects before correctingto the reference temperature. This procedure can also be usedfor viscous liquids by allow

38、ing sufficient time for the thermo-hydrometer to reach temperature equilibrium.6. Apparatus6.1 Glass Thermohydrometers, as specified in SpecificationE100 (shown in Fig. 1), and graduated in:6.1.1 Kilograms/cubic metre (kg/m3) and degrees Celsiusfor density hydrometers, as shown in Table 1.6.1.2 Degr

39、ees API (API) and degrees Fahrenheit for hy-drometers measuring in API Gravity, as shown in Table 2.6.1.3 The user should ascertain that the instruments used forthis procedure conform to the requirements set out above withrespect to materials, dimensions, and scale errors. In caseswhere the instrume

40、nt is provided with a calibration certificateissued by a recognized standardizing body, the instrument isclassed as certified and the appropriate corrections for themeniscus effect, the thermal glass expansion effect, and alter-native calibration temperature effects shall be applied to theFIG. 1 Typ

41、ical Thermohydrometer DesignsD6822 12b (2017)3observed readings prior to corrections. Instruments that satisfythe requirements of this test method, but are not provided witha recognized calibration certificate, are classed as uncertifiedand the appropriate corrections for the meniscus effect, thethe

42、rmal glass expansion effect, and alternative calibrationtemperature effects shall be applied to the observed readingsprior to corrections.6.2 Hydrometer Cylinders, clear glass, plastic, or metal. Forconvenience of pouring, the cylinder may have a pouring lip.The inside diameter shall be at least 25

43、mm (1 in.) greater thanthe outside diameter of the thermohydrometer used. The heightof the cylinder shall be such that the bottom of the thermohy-drometer clears the bottom of the cylinder by at least 25 mm(1 in.) when suspended in the sample test portion.6.2.1 For field testing, a sample thief of s

44、uitable dimensionsmay be more convenient than a hydrometer cylinder. Theliquid level shall be level with the top of the thief.6.3 Temperature Bath, to control temperature close to thebulk hydrocarbon temperature or to control temperature closeto the reference temperature of 15 C or 60 F.7. Sampling,

45、 Test Specimens, and Test Units7.1 Unless otherwise specified, samples of non-volatilepetroleum and petroleum products shall be taken by theprocedures described in Practices D4057 (API MPMS Chapter8.1) and D4177 (API MPMS Chapter 8.2).7.2 Samples of volatile crude petroleum or petroleum prod-ucts ar

46、e preferably taken by Practice D4177 (API MPMSChapter 8.2), 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,

47、including the transfer of the sample to a chilledcontainer immediately 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 volati

48、le crude petro-leum or petroleum products containing water or 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 7.3.4) will give some guidanceon sample integrity maintenance.7.3.1 Volatile

49、Crude Petroleum and Petroleum ProductsHaving an RVP Greater 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 anexpected pour point above 10 C, or a cloud point or WATabove 15 C, warm the sample to a temperature that issufficient for ensuring the material is fluid enough to provi