1、Designation: D 6822 02 (Reapproved 2008)Designation: Manual of Petroleum Measurement Standards (MPMS), Chapter 9.3An American National StandardStandard Test Method forDensity, Relative Density, and API Gravity of CrudePetroleum and Liquid Petroleum Products byThermohydrometer Method1This standard is
2、 issued under the fixed designation D 6822; 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 (e) indicates an editorial c
3、hange since the last revision or reapproval.1. Scope1.1 This test method covers the determination, using a glassthermohydrometer, of the density, relative density (specificgravity), or API gravity of crude petroleum and liquid petro-leum products with Reid vapor pressures of 101.325 kPa(14.696 psi)
4、or less. Values are determined at existing tempera-tures and corrected to 15C or 60F by means of internationalstandard tables.1.2 The values stated in either SI units or inch pound-unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore
5、, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in nonconformancewith the standard.1.3 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
6、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 1298 Test Method for Density, Relative Density (SpecificGravity), or API Gravity of Crude Petroleum and LiquidPetroleum Products by
7、Hydrometer Method (API MPMSChapter 9.1)D 6300 Practice for Determination of Precision and BiasData for Use in Test Methods for Petroleum Products andLubricantsE 100 Specification for ASTM Hydrometers2.2 API Standards:3MPMS Chapter 9.1 Hydrometer Test Method for Density,Relative Density (Specific Gra
8、vity) or API Gravity ofCrude Petroleum and Liquid Petroleum Products (ASTMTest Method D 1298)MPMS Chapter 11.1 Temperature and Pressure VolumeCorrection Factors for Generalized Crude Oils, RefinedProducts, and Lubricating Oils2.3 ASTM Adjuncts:Adjunct to D 1250, Guide for Use of the Petroleum Mea-su
9、rement 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 60/60F, represented by:API 5 141.5 / relative density 60/60F!# 2 131.5 (1)3.1.1.1 DiscussionNo statement of reference temperatureis r
10、equired, as 60F is included in the definition.3.1.2 density, nthe mass of liquid per unit volume at 15Cand 101.325 kPa with the standard unit of measurement beingkilograms per cubic metre (kg/m3).3.1.2.1 DiscussionOther reference temperatures, such as20C may be used for some products or in some loca
11、tions. Lesspreferred units of measurement; for example, kg/Lor g/mL, arestill in use.3.1.3 observed values, nhydrometer readings observed ata temperature other than the defined reference temperature.3.1.3.1 DiscussionThese values are only hydrometerreadings and not density, relative density, or API
12、gravity at thetemperature.3.1.4 relative density, nthe ratio of the mass of a givenvolume of liquid at a specific temperature to the mass of an1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and the API Committee on Petroleum Measure-ment, and is
13、 the direct responsibility of Subcommittee D02.02/COMQ, the jointASTM-API Committee on Static Petroleum Measurement.Current edition approved Feb. 1, 2008. Published April 2008. Originallyapproved in 2002. Last previous edition approved in 2002 as D 6822-02.2For referenced ASTM standards, visit the A
14、STM 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., NW, Wash-ington, DC 20005-4070, www.api
15、.org.4Available from ASTM International Headquarters. Order Adjunct No.ADJD1250CD. Original adjunct produced in 2004.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.equal volume of pure water at the same or different tempera-ture. Bo
16、th reference temperatures shall be explicitly stated.3.1.4.1 DiscussionCommon reference temperatures in-clude 15/15C, 60/60F, 20/20C, and 20/4C. The historicterm specific gravity may still be found.3.1.5 thermohydrometer, na glass hydrometer with aself-contained thermometer.4. Summary of Test Method
17、4.1 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 surface of theliquid with the vertical scale of the hydrometer after tempera
18、-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 Guide D 1250/API MPMS Chapter 11.1) andobserved temperature from the enclosed thermometer.5. Significance
19、and Use5.1 Density and API gravity are used in custody transferquantity calculations and to satisfy transportation, storage, andregulatory requirements. Accurate determination of density orAPI gravity of crude petroleum and liquid petroleum productsis necessary for the conversion of measured volumes
20、 tovolumes at the standard temperatures of 15C or 60F.5.2 Density andAPI gravity are also factors that indicate thequality of crude petroleum. Crude petroleum prices are fre-quently posted against values in kg/m3or in degrees API.However, this property of petroleum is an uncertain indicationof its q
21、uality unless correlated with other properties.5.3 Field of ApplicationBecause the thermohydrometerincorporates both the hydrometer and thermometer in onedevice, it is more applicable in field operations for determiningdensity or API gravity of crude petroleum and other liquidpetroleum products. The
22、 procedure is convenient for gatheringmain trunk pipelines and other field applications where limitedlaboratory facilities are available. The thermohydrometermethod may have limitations in some petroleum densitydeterminations. When this is the case, other methods such asTest Method D 1298 (API MPMS
23、Chapter 9.1) may be used.5.4 This test method is suitable for determining the density,relative density, or API gravity of low viscosity transparent oropaque liquids, or both. This test method, when used foropaque liquids, requires the use of a meniscus correction (see7.2).6. Apparatus6.1 Glass Therm
24、ohydrometers, as specified in SpecificationE 100 (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 Degrees API (API) and degrees Fahrenheit for hy-drometers measuring in API Gravity, as shown in Table 2.6.2 H
25、ydrometer Cylinders, clear glass, plastic, or metal. Forconvenience of pouring, the cylinder may have a pouring lip.The inside diameter shall be at least 25 mm (1 in.) greater thanthe outside diameter of the thermohydrometer used. The heightof the cylinder shall be such that the bottom of the thermo
26、hy-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 suitable dimensionsmay be more convenient than a hydrometer cylinder. Theliquid level shall be level with the top of the thief.6.3 Temperature B
27、ath, to control temperature close to thebulk hydrocarbon temperature or to control temperature closeto the reference temperature of 15C or 60F.7. Procedure7.1 Effect of Test Temperature:7.1.1 The density or API gravity determined by the thermo-hydrometer method is most accurate at or near the refere
28、ncetemperature of 15C or 60F. Other temperatures within therange of the enclosed thermometer may be used, if consistentwith the type of sample and the necessary limiting conditionsshown in Table 3.TABLE 1 Density ThermohydrometersASTM Hydrometer No. Density, Range, kg/m3300H 600 to 650301H 650 to 70
29、0302H 700 to 750303H 750 to 800304H 800 to 850305H 850 to 900306H 900 to 950307H 950 to 1000308H 1000 to 1050309H 1050 to 1100HydrometerTotal length, mm 374 to 387Body diameter, mm 18 to 25Stem diameter, mm, min 4.0Hydrometer ScaleStandard temperature, C 15Subdivisions, kg/m30.5Short intermediate li
30、nes at, kg/m31Long intermediate lines at, kg/m35Main (numbered) lines at, kg/m310Scale error at any point not to exceed, kg/m30.5Length of nominal scale, mm 125 to 145Scale extension beyond nominal range limits, kg/m32.5Thermometer ScaleRange, CDesignation L 20 to +65Designation M 0 to +85Designatio
31、n H +20 to +105Immersion totalSubdivisions, C 1.0Intermediate lines at, C 5Main (numbered) lines at, C 10Scale error at any point not to exceed, C 1.0Scale length, mm 80 to 100D 6822 02 (2008)27.1.2 If the test temperature is significantly different fromthe reference temperature of 15C or 60F, the e
32、xpansion orcontraction of the glass may affect the calibration of thethermohydrometer. A hydrometer correction factor (HYC) maybe applied to the measured density value to provide a correctedTABLE 2 API Gravity ThermohydrometersNOTEFor petroleum products and other liquids of similar surface tensions
33、(33 dynes/cm or less).Thermometer Scale in Body Thermometer Scale in StemASTM HydrometerNo.Nominal API GravityRange, degreesASTM HydrometerNo.Nominal API GravityRange, degrees41H-66 15 to 23 71H-62 1 to +1142H-66 22 to 30 72H-62 9 to 2143H-66 29 to 37 73H-62 19 to 3144H-66 36 to 44 74H-62 29 to 4145
34、H-66 43 to 5151H-62 1 to +1152H-62 9 to 2153H-62 19 to 3154H-62 29 to 4155H-62 39 to 5156H-62 49 to 6157H-62 59 to 7158H-62 69 to 8159H-62 79 to 9160H-62 89 to 101HydrometerThermometer Scalein BodyThermometer Scalein StemTotal length, mm 374 to 387 374 to 387Body diameter, mm 18 to 25 23 to 27Stem d
35、iameter, mm, min 4.0 6.0Hydrometer ScaleStandard temperature, F 60Subdivisions, API 0.1Intermediate lines at, API 0.5Main (numbered) lines at, API 1.0Scale error at any point not to exceed, API 0.1Length of nominal scale, mm 125 to 145Thermometer ScaleThermometer Scalein BodyThermometer Scalein Stem
36、Range, FADesignation L 0 to 150Designation M 30 to 180 30 to 220Designation H 60 to 220Immersion Total TotalSubdivisions, F 2 2Intermediate lines at, F 10 10Main (numbered) lines at, F 20 20Scale error at any point not to exceed, F 1 1Scale length, mm 80 to 110 105 to 145AIndication of the thermomet
37、er range is made by the use of the listed designation used as a suffix to the ASTM hydrometer number. For example, 54HL is an instrumentwith an API gravity range of 29 to 41API and a thermometer range of 0 to 150F. An instrument with the same gravity range but a thermometer range of 60 to 220F would
38、be designated 54HH. The number 57HM would identify an instrument with an API gravity range of 59 to 71API and a thermometer range of 30 to 180F.TABLE 3 Limiting Conditions and Test TemperaturesSample Type Initial Boiling Point Other Limits Test TemperatureVolatile 120C (250F) or lower Cool in origin
39、al closed container to 18C (65F) or lowerVolatile and viscous 120C (250F) or lower Viscosity too highat 18C (65F)Heat to minimum temperature to obtain sufficient fluidityNon-volatile Above 120C (250F) Use any temperature between 18C and 90C (0 and 195F)as convenientMixture with non-petroleum product
40、s . . . Test at 15 6 0.2C or 60 6 0.5FD 6822 02 (2008)3FIG. 1 Typical Thermohydrometer DesignsD 6822 02 (2008)4reading. Historically, the following equations have been usedwithin volume correction factor tables.rcorrected5rtest3 HYC (2)where:HYC = hydrometer thermal correction factor,rcorrected= tes
41、t density, corrected for the effects of tem-perature on the thermohydrometer, andrtest= test density, as observed by reading the ther-mohydrometer.HYC 5 1 2 0.00001278t 2 60! 2 0.0000000062t 2 60!2(3)where:t = observed temperature (F) orHYC 5 1 2 0.000023t 2 15! 2 0.00000002t 2 15!2(4)where:t = obse
42、rved temperature (C).7.1.2.1 All parties affected by the measurement shouldagree upon the need for and the method of correction.7.1.3 When the thermohydrometer value is used to selectfactors for correcting volumes to standard temperatures, thethermohydrometer reading preferably should be made at ate
43、mperature within 63C (65F) of the temperature at whichthe bulk volume of the oil was measured (see Note 1).However, when appreciable amounts of light fractions may belost during determination at the bulk oil temperature, the limitsgiven in Table 3 shall be applied.NOTE 1Volume and density correction
44、 tables are based on averageexpansion for a number of typical materials. Since the same coefficientswere used in computing both sets of tables, corrections made over thesame temperature interval minimize errors arising from possible differ-ences between the coefficients of the material under test an
45、d the standardcoefficients. This effect becomes more important as temperatures divergesignificantly from 15C or 60F.7.2 Density Measurement:7.2.1 Adjust the temperature of the sample in accordancewith Table 3. For field testing, test temperatures other thanthose listed in Table 3 may be used, howeve
46、r, accuracy may besacrificed. The hydrometer cylinder shall be at approximatelythe same temperature as the sample to be tested.7.2.2 Transfer the sample into the clean hydrometer cylinderwithout splashing, so as to avoid the formation of air bubblesand to reduce, to a minimum, the evaporation of the
47、 lowerboiling constituents of the more volatile samples (WarningExtremely flammable. Vapors may cause a flash fire). For themore volatile samples, transfer to the hydrometer cylinder bysiphoning (WarningSiphoning by mouth could result iningestion of sample). Use a rubber aspirator bulb to siphon the
48、more volatile samples. Remove any air bubbles formed, afterthey have collected on the surface of the sample, by touchingthem with a piece of clean absorbent paper before inserting thethermohydrometer. For field testing, the thermohydrometermay be inserted directly into a sampling thief. Place thecyl
49、inder containing the sample in a vertical position in alocation free from air currents. Take precautions to prevent thetemperature of the sample from changing appreciably duringthe time necessary to complete the test.7.2.2.1 During this period, the temperature of the surround-ing medium should not change more than 3C (5F).7.2.3 Lower and raise the thermohydrometer no more thantwo scale divisions in the sample cylinder to minimize vaporloss and in such a manner that the stem will not be wettedh
