1、Designation: D6822 12aAPI 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 In
7、terconver-sion Procedures or Adjunct to D1250, Guide for Use of thePetroleum Measurement Tables (API MPMS Chapter 11.1), orboth, or tables as applicable.1.4 The initial thermohydrometer reading shall be recordedbefore performing any calculations. The calculations requiredin Section 9 shall be applie
8、d 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 procedure for verifying or
9、 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 is theresponsibility of
10、 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 Density, Relative Density (
11、SpecificGravity), or API Gravity of Crude Petroleum and LiquidPetroleum Products by Hydrometer Method (API MPMSChapter 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 MPMS Ch
12、apter 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 Hydrometers2.2 API Standards:3
13、MPMS Chapter 8.1 Practice for Manual Sampling of Petro-leum and Petroleum ProductsMPMS Chapter 8.2 Practice for Automatic Sampling ofPetroleum and Petroleum ProductsMPMS Chapter 8.3 Practice for Mixing and Handling ofLiquid Samples of Petroleum and Petroleum Products(ASTM Practice D5854)1This test m
14、ethod 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 D02.02.09 on DensityDetermination (API MPMS Chapter 9.0).Current edition approved May 15, 2012. Published Octobe
15、r 2012. Originallyapproved in 2002. Last previous edition approved in 2012 as D6822-12. DOI:10.1520/D6822-12A.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 st
16、andards Document Summary page onthe ASTM website.3Available from American Petroleum Institute (API), 1220 L. St., NW, Wash-ington, DC 20005-4070, www.api.org.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Cons
17、hohocken, PA 19428-2959, United States.MPMS Chapter 9.1 Hydrometer Test Method for Density,Relative Density (Specific Gravity) or API Gravity ofCrude Petroleum and Liquid Petroleum Products (ASTMTest Method D1298)MPMS Chapter 11.12004, including Addendum12007 Temperature and Pressure Volume Correcti
18、onFactors for Generalized Crude Oils, Refined Products, andLubricating Oils2.3 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 special function of r
19、elativedensity 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 standard unit of measure
20、ment 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 observed values, nhydrometer readings observed ata temperat
21、ure 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 to the mass of anequal v
22、olume of pure water at the same or different tempera-ture. Both 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 hydromet
23、er 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 graduation nearest to theapparent intersection of the horizontal plane surface of thel
24、iquid 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 Guide D1250/API MPMS Chapter 11.1) andobserve
25、d 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. Accurate determination of density orAPI gravity of crude petroleum and liquid petroleum
26、 productsis necessary for the conversion of measured volumes 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, t
27、his 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 applicable in field operations for determiningdensity or API gravit
28、y 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 limitations in some petroleum densitydeterminations. When this is
29、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 oropaque liquids, or both. This procedure, when used for opaqueliquids, requires the use of a
30、meniscus 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
31、allowing 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
32、 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 procedure conform to the requirements set out above withrespect to materials, dimensions, and scale errors. In caseswhere the ins
33、trument 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 theobser
34、ved 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, thethermal glass expansion effect, and alternative calibr
35、ationtemperature 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 mm (1 in.) greater than4Available from ASTM Interna
36、tional Headquarters. Order Adjunct No.ADJD1250CD. Original adjunct produced in 2004.D6822 12a2the 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 (1in.) when suspended
37、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 close to thebulk hydrocarbon temperature or to control tem
38、perature 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 D4177 (API MPMS Chapter 8.2).7.2 Samples of volatile crud
39、e 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 mayFIG. 1 Typical Thermohydrometer DesignsD6822 12a3affect the accuracy of the density measurement.
40、 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 shall b
41、e 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 section
42、s (7.3.1 to 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 contai
43、ners 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 fluid e
44、nough 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 possib
45、le, 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
46、 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 8.1.1 and Note 4).7.4 Additional information on the
47、mixing and handling ofliquid samples will be found in Practice D5854/API MPMSChapter 8.3.8. Apparatus Verification or Certification8.1 Hydrometers and thermometers shall be verified inaccordance with the procedures in Annex A1.9. Procedure9.1 Effect of Test Temperature:9.1.1 The density or API gravi
48、ty 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 necessary limiting conditionsshown in Table 3.9.1.2 Bring the sam
49、ple to the test temperature which shall besuch that the sample is sufficiently fluid but not as high as tocause the loss of light components, or so low as to result in theappearance of wax in the test portion.NOTE 2The volume and density, the relative density, and the APIcorrections in the volume correction procedures are based on the averageexpansions of a number of typical materials. Since the same coefficientswere used in compiling each set of tables, corrections made over the sametemperature interval minimize errors arising from poss
