1、Designation: D 6822 02Designation: 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 issued under the
2、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 change since the la
3、st 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) or less. Values ar
4、e 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, eachsystem shall
5、 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 establish appro-pr
6、iate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:D 1298 Test Method for Density, Relative Density (SpecificGravity), or API Gravity of Crude Petroleum and LiquidPetroleum Products by Hydrometer Method (
7、API MPMSChapter 9.1)2D 6300 Practice for Determination of Precision and BiasData for Use in Test Methods for Petroleum Products andLubricants2E 100 Specification for ASTM Hydrometers32.2 Adjunct:Adjunct to D 1250 Guide for Petroleum MeasurementTables (API MPMS Chapter 11.1)42.3 API Standards:5MPMS C
8、hapter 9.1 Hydrometer Test Method for Density,Relative Density (Specific Gravity) or API Gravity ofCrude Petroleum and Liquid Petroleum Products (ASTMTest Method D 1298)MPMS Chapter 11.1 Volume Correction Factors3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 API gravity (API)
9、, 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 required, as 60F is included in the definition.3.1.2 density, nthe mass of liquid per unit volume at 15Cand 101.325 kPa with th
10、e 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 locations. Lesspreferred units of measurement; for example, kg/L or g/mL, arestill in use.3.1.3 observed values, nhydrometer readi
11、ngs 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 gravity at thetemperature.3.1.4 relative density, nthe ratio of the mass of a givenvolume of liquid at a specific temperature
12、 to the mass of anequal volume of pure water at the same or different tempera-ture. Both reference temperatures shall be explicitly stated.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
13、 direct responsibility of Subcommittee D02.02/COMQ, the jointASTM-API Committee on Static Petroleum Measurement.Current edition approved Aug. 10, 2002. Published November 2002.2Annual Book of ASTM Standards, Vol 05.04.3Annual Book of ASTM Standards, Vol 14.03.4Annual Book of ASTM Standards, Vol 05.0
14、1.5Available from American Petroleum Institute, 1220 L St., NW, Washington, DC20005.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.4.1 DiscussionCommon reference temperatures in-clude 15/15C, 60/60F, 20/20C, and 20/4C. The histo
15、ricterm specific gravity may still be found.3.1.5 thermohydrometer, na glass hydrometer with aself-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 g
16、raduation nearest to theapparent intersection of the horizontal plane surface 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 Measurem
17、ent Tables (the appropri-ate adjunct to Guide D 1250/API MPMS Chapter 11.1) andobserved temperature 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. A
18、ccurate determination of density orAPI gravity of crude petroleum and liquid petroleum productsis necessary for the conversion of measured volumes tovolumes at the standard temperatures of 15C or 60F.5.2 Density and API gravity are also factors that indicate thequality of crude petroleum. Crude petr
19、oleum prices are fre-quently 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 on
20、edevice, it is more applicable 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 thermohydro
21、metermethod may have limitations in some petroleum densitydeterminations. When this is the case, other methods such asTest Method D 1298 (API MPMS 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 oropa
22、que liquids, or both. This test method, when used foropaque liquids, requires the use of a meniscus correction (see7.2).6. Apparatus6.1 Glass Thermohydrometers, as specified in SpecificationE 100 (shown in Fig. 1), and graduated in:6.1.1 Kilograms/cubic metre (kg/m3) and degrees Celsiusfor density h
23、ydrometers, 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 Hydrometer Cylinders, clear glass, plastic, or metal. Forconvenience of pouring, the cylinder may have a pouring lip.The inside diameter shall be at least
24、 25 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
25、of suitable 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 15C or 60F.7. Procedu
26、re7.1 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 referencetemperature of 15C or 60F. Other temperatures within therange of the enclosed thermometer may be used, if consistentwith the type of sample and the ne
27、cessary limiting conditionsshown in Table 3.7.1.2 If the test temperature is significantly different fromthe reference temperature of 15C or 60F, the expansion orcontraction of the glass may affect the calibration of thethermohydrometer. A hydrometer correction factor (HYC) maybe applied to the meas
28、ured density value to provide a correctedreading. Historically, the following equations have been usedwithin volume correction factor tables.rcorrected5rtest3 HYC (2)TABLE 1 Density ThermohydrometersASTM Hydrometer No. Density, Range, kg/m3300H 600 to 650301H 650 to 700302H 700 to 750303H 750 to 800
29、304H 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 lines at, kg/m31Long intermediate
30、 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 +85Designation H +20 to +105Immersion totalS
31、ubdivisions, 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 100D6822022TABLE 2 API Gravity ThermohydrometersNOTEFor petroleum products and other liquids of similar surface tensions (33 dynes/cm or less).Thermometer Sca
32、le 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 4145H-66 43 to 5151H-62 1 to +1152H-62 9
33、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 diameter, mm, min 4.0 6.0Hydrometer Sc
34、aleStandard 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 StemRange, FADesignation L 0 to 150Design
35、ation 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 thermometer range is made by the use of the li
36、sted 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 wouldbe designated 54HH. The number 57HM w
37、ould 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 original closed container to 18C (65F) or l
38、owerVolatile 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 products . . . Test at 15 6 0.2C or 60 6 0.5
39、FD6822023FIG. 1 Typical Thermohydrometer DesignsD6822024where:HYC = hydrometer thermal correction factor,rcorrected= test 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 0.0
40、000000062t 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 = observed 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 sel
41、ectfactors for correcting volumes to standard temperatures, thethermohydrometer reading preferably should be made at atemperature 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 de
42、termination at the bulk oil temperature, the limitsgiven in Table 3 shall be applied.NOTE 1Volume and density correction 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 temper
43、ature interval minimize errors arising from possible differ-ences between the coefficients of the material under test and 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 samp
44、le in accordancewith Table 3. For field testing, test temperatures other thanthose listed in Table 3 may be used, however, 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 c
45、ylinderwithout splashing, so as to avoid the formation of air bubblesand to reduce, to a minimum, the evaporation of the lowerboiling constituents of the more volatile samples (WarningExtremely flammable. Vapors may cause a flash fire). For themore volatile samples, transfer to the hydrometer cylind
46、er bysiphoning (WarningSiphoning by mouth could result iningestion of sample). Use a rubber aspirator bulb to siphon themore 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
47、thethermohydrometer. For field testing, the thermohydrometermay be inserted directly into a sampling thief. Place thecylinder 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
48、 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 w
49、ill not be wettedhigher than the approximate floating position.7.2.3.1 Keep the rest of the stem dry, as unnecessary liquidon the stem changes the effective weight of the instrument, andso affects the reading obtained.7.2.3.2 Gently lower the thermohydrometer into the centerof the hydrometer cylinder. When the thermohydrometer hassettled, ensure it is not resting on the bottom of the cylinder bydepressing it about two scale divisions into the liquid. Give thethermohydrometer a slight spin, allowing
