1、Designation: D6822 12bAPI Designation: 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.1
3、. Scope*1.1 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 to15C or 60F by means of a series of calculations andinternational standard tables.1.2 The initial thermohydrometer readings obtained areuncorrected hydrometer readings and n
5、ot density measure-ments. Readings are measured on a thermohydrometer at eitherthe reference temperature or at another convenient tempera-ture, and readings are corrected for the meniscus effect, thethermal glass expansion effect, alternate calibration tempera-ture 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. The values given in parentheses are for informationonly.1.7 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It i
10、s 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:2D1250 Guide for Use of the Petroleum Measurement TablesD1298 Test Method for Densi
11、ty, Relative Density, or APIGravity of Crude Petroleum and Liquid Petroleum Prod-ucts by Hydrometer Method (API MPMS Chapter 9.1)D4057 Practice for Manual Sampling of Petroleum andPetroleum Products (API MPMS Chapter 8.1)D4177 Practice for Automatic Sampling of Petroleum andPetroleum Products (API M
12、PMS Chapter 8.2)D5854 Practice for Mixing and Handling of Liquid Samplesof Petroleum and Petroleum Products (API MPMS Chapter8.3)D6300 Practice for Determination of Precision and BiasData for Use in Test Methods for Petroleum Products andLubricantsE100 Specification for ASTM Hydrometers1This test me
13、thod is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and the API Committee on Petroleum Measure-ment, and is the direct responsibility of Subcommittee D02.02 /COMQ, the jointASTM-API Committee on Hydrocarbon Measurement for Custody Transfer (JointASTM-API).Current
14、 edition approved June 1, 2012. Published October 2012. Originallyapproved in 2002. Last previous edition approved in 2012 as D6822-12a. DOI:10.1520/D6822-12B.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of
15、ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.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.2.2 API Standards:3MP
16、MS Chapter 8.1 Practice for Manual Sampling of Petro-leum and Petroleum Products (ASTM Practice D4057)MPMS Chapter 8.2 Practice for Automatic Sampling ofPetroleum and Petroleum Products (ASTM PracticeD4177)MPMS Chapter 8.3 Practice for Mixing and Handling ofLiquid Samples of Petroleum and Petroleum
17、Products(ASTM Practice D5854)MPMS Chapter 9.1 Hydrometer Test Method for Density,Relative Density or API Gravity of Crude Petroleum andLiquid Petroleum Products (ASTM Test Method D1298)MPMS Chapter 11.1 Temperature and Pressure VolumeCorrection Factors for Generalized Crude Oils, RefinedProducts, an
18、d Lubricating Oils (Adjunct toASTM D1250)MPMS Chapter 11.5 Density/Weight/Volume Intraconver-sion2.3 ASTM Adjuncts:Adjunct to D1250 Guide for Use of the 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
19、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 the sta
20、ndard 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.Less preferred units of measurement, for example, kg/L org/mL, are still in use.3.1.3 hydrometer reading, nthe point on the
21、hydrometerscale at which the surface of the liquid cuts the scale.3.1.3.1 DiscussionIn practice for transparent fluids thiscan be readily determined by aligning the surface of the liquidon both sides of the hydrometer and reading the Hydrometerscale where these surface readings cut the scale (Hydrom
22、eterReading Observed). For nontransparent fluids the point atwhich the liquid surface cuts the Hydrometer scale cannot bedetermined directly and requires a correction (Meniscus Cor-rection). The value represented by the point (Meniscus Read-ing) at which the liquid sample rises above the main surfac
23、e ofthe liquid subtracted from the value represented by where themain surface of the liquid cuts the Hydrometer scale is theamount of the correction or Meniscus correction. This menis-cus correction is documented and then subtracted from thevalue represented by the Meniscus Reading to yield theHydro
24、meter Reading corrected for the Meniscus (HydrometerReading Observed, Meniscus Corrected).3.1.4 observed values, nhydrometer readings observed ata temperature other than the defined reference temperature.3.1.4.1 DiscussionThese values are only hydrometerreadings and not density, relative density, or
25、 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 anequal volume of pure water at the same or different tempera-ture. Both reference temperatures shall be explicitly stated.3.1.5.1 DiscussionCommon refere
26、nce temperatures in-clude 15/15C, 60/60F, 20/20C, and 20/4C. The historicterm specific gravity may still be found.3.1.6 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
27、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-ture equilibrium has been reached. The observed thermohy-drometer reading is reduce
28、d to the reference temperature valueby means of the Petroleum Measurement Tables (the appropri-ate adjunct to Adjunct to D1250 Guide for Petroleum Mea-surement Tables (API MPMS Chapter 11.1) and observedtemperature from the enclosed thermometer.5. Significance and Use5.1 Density and API gravity are
29、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 tovolumes at the standard temperatures
30、 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 quality unless correlated with other pro
31、perties.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 procedure is convenient for gatheringm
32、ain 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 D1298 (API MPMS Chapter 9.1) may be used.5.4 This proced
33、ure is suitable for determining the density,relative density, or API gravity of low viscosity, transparent oropaque liquids, or both. This procedure, when used for opaqueliquids, requires the use of a meniscus correction (see 9.2).Additionally for both transparent and opaque fluids the read-ings sha
34、ll be corrected for the thermal glass expansion effectand alternate calibration temperature effects before correctingto the reference temperature. This procedure can also be used3Available from American Petroleum Institute (API), 1220 L. St., NW, Wash-ington, DC 20005-4070, www.api.org.4Available fr
35、om ASTM International Headquarters. Order Adjunct No.ADJD1250. Original adjunct produced in 1983.D6822 12b2for viscous liquids by allowing sufficient time for the thermo-hydrometer to reach temperature equilibrium.6. Apparatus6.1 Glass Thermohydrometers, as specified in SpecificationE100 (shown in F
36、ig. 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 2.6.1.3 The user should ascertain that the instruments used forthis
37、 procedure conform to the requirements set out above withrespect 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 the
38、meniscus effect, 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 withFIG. 1 Typical Thermohydrometer DesignsD6822 12b
39、3a recognized calibration certificate, are classed as uncertifiedand the appropriate corrections for the meniscus effect, thethermal glass expansion effect, and alternative calibrationtemperature effects shall be applied to the observed readingsprior to corrections.6.2 Hydrometer Cylinders, clear gl
40、ass, 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 thermohy-drometer clears the bottom
41、 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 Bath, to control temperature c
42、lose to thebulk hydrocarbon temperature or to control temperature closeto the reference temperature of 15C or 60F.7. Sampling7.1 Unless otherwise specified, samples of non-volatilepetroleum and petroleum products shall be taken by theprocedures described in Practices D4057 (API MPMS Chapter8.1) and
43、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), using a variable volume (floating piston) samplereceiver to minimize any loss of light components which mayaffect the accuracy of the density meas
44、urement. In the absenceof this facility, extreme care shall be taken to minimize theselosses, 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
45、 shall be taken to maintain the integrity of thesample during this operation. Mixing of volatile 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
46、 sections (7.3.1-7.3.4) will give some guidanceon sample integrity maintenance.7.3.1 Volatile 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 c
47、ontainers 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 10C, or a cloud point or WATabove 15C, warm the sample to a temperature that is sufficientfor ensuring the material is fl
48、uid enough to provide adequatemixing without excessively heating the material that wouldotherwise compromise the integrity of the sample. Samplesheated 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 p
49、ossible, mix the sample inits original closed container in order to minimize the loss oflight components.7.3.3 Waxy DistillateWarm the sample to a temperaturethat 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 m
