ASTM D287-2012a Standard Test Method for API Gravity of Crude Petroleum and Petroleum Products (Hydrometer Method).pdf

1、Designation: D287 12aStandard Test Method forAPI Gravity of Crude Petroleum and Petroleum Products(Hydrometer Method)1This standard is issued under the fixed designation D287; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the yea

2、r 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.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This test method covers the det

3、ermination by means ofa glass hydrometer in conjunction with a series of calculationsof the API gravity of crude petroleum and petroleum productsnormally handled as liquids and having a Reid vapor pressure(Test Method D323) of 101.325 kPa (14.696 psi) or less.Gravities are determined at 60F (15.56C)

4、, or converted tovalues at 60F, by means of Adjunct to D1250 Guide forPetroleum Measurement Tables (API MPMS Chapter 11.1).These tables are not applicable to nonhydrocarbons or essen-tially pure hydrocarbons such as the aromatics.NOTE 1The international version of this test method is described inTes

5、t Method D1298.1.2 The initial values obtained are uncorrected hydrometerreadings and not density measurements. Values are measuredon a hydrometer at either the reference temperature or atanother convenient temperature, and readings corrected for themeniscus effect, the thermal glass expansion effec

6、t, alternatecalibration temperature effects and to the reference temperatureby means of volume correction tables.1.3 The hydrometer readings determined shall be recordedbefore performing any calculations. Then the calculationsrequired in Section 9 shall be performed and documentedbefore using the fi

7、nal result in a subsequent calculationprocedure (measurement ticket calculation, meter factor calcu-lation, or base prover volume determination).1.4 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are p

8、rovided for information onlyand are not considered standard.1.5 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-priate safety and health practices and determine the applica-b

9、ility of regulatory limitations prior to use. For specificwarning statement, see 8.3.2. Referenced Documents2.1 ASTM Standards:2D323 Test Method for Vapor Pressure of Petroleum Prod-ucts (Reid Method)D1250 Guide for Use of the Petroleum Measurement Tables(API MPMS Chapter 11.1)D1298 Test Method for

10、Density, Relative Density (SpecificGravity), or API Gravity of Crude Petroleum and LiquidPetroleum Products by Hydrometer Method (API MPMSChapter 9.1)D6822 Test Method for Density, Relative Density, and APIGravity of Crude Petroleum and Liquid Petroleum Prod-ucts by Thermohydrometer Method (API MPMS

11、 Chapter9.3)E1 Specification for ASTM Liquid-in-Glass ThermometersE100 Specification for ASTM Hydrometers2.2 EI Standards:3Specifications for IP Standard ThermometersIP Specifications for Petroleum Hydrometers2.3 API Standards:4MPMS Chapter 9.1 Test Method for Density, Relative Den-sity (Specific Gr

12、avity), orAPI Gravity of Crude Petroleumand Liquid Petroleum Products by Hydrometer Method(ASTM D1298)MPMS Chapter 9.3 Test Method for Density, Relative Den-sity, and API Gravity of Crude Petroleum and LiquidPetroleum Products by Thermohydrometer Method(ASTM D6822)MPMS Chapter 11.1-2004, including A

13、ddendum12007 Temperature and Pressure Volume Correction1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.02 /COMQ, the jointASTM-API Committee on Hydrocarbon Measurement forCustody Transfer, on Hy

14、drocarbon Measurement for Custody Transfer (JointASTM-API).Current edition approved May 15, 2012. Published October 2012. Originallyapproved in 1928. Last previous edition approved in 2012 as D28712. DOI:10.1520/D0287-12A.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontac

15、t 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 Energy Institute, 61 New Cavendish St., London, WIG 7AR,U.K., http:/www.energyinst.org.4Available from American Petroleum I

16、nstitute (API), 1220 L. St., NW, Wash-ington, DC 20005-4070, http:/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 Conshohocken, PA 19428-2959, United States.Factors for Generalized Crude Oils, Refi

17、ned Products, andLubricating Oils2.4 ASTM Adjuncts:Adjunct to D1250 Guide for Petroleum Measurement Tables(API MPMS Chapter 11.1)53. Terminology3.1 Definitions:3.1.1 API gravity, na special function of relative density60/60F (15.56/15.56C), represented by:API 5 141.5/ relative density 60/60F 2 131.5

18、 (1)No statement of reference temperature is required, since60F is included in the definition.3.1.2 specific gravity, nhistorical term, no longer used,which has been replaced by relative density.4. Summary of Test Method4.1 This test method is based on the principle that thegravity of a liquid varie

19、s directly with the depth of immersionof a body floating in it. The floating body, which is graduatedby API gravity units in this test method, is called an APIhydrometer.4.2 The API gravity is read by observing the freely floatingAPI hydrometer and noting the graduation nearest to theapparent inters

20、ection of the horizontal plane surface of theliquid with the vertical scale of the hydrometer, after tempera-ture equilibrium has been reached. The temperature of thesample is read from a separate accurate ASTM thermometer inthe sample.4.3 The observed hydrometer reading is corrected for themeniscus

21、 effect, the thermal glass expansion effect, alternatecalibration temperature effects and reduced to the referencetemperature by means of the volume correction tables. Ifnecessary, the hydrometer cylinder and its contents are placedin a constant temperature bath to avoid excessive temperaturevariati

22、on during the test.5. Significance and Use5.1 Accurate determination of the gravity of petroleum andits products is necessary for the conversion of measuredvolumes to volumes at the standard temperature of 60F(15.56C).5.2 This procedure is most suitable for determining the APIgravity of low viscosit

23、y transparent liquids. This test methodcan also be used for viscous liquids by allowing sufficient timefor the hydrometer to reach temperature equilibrium, and foropaque liquids by employing a suitable meniscus correction.Additionally for both transparent and opaque fluids the read-ings shall be cor

24、rected for the thermal glass expansion effectbefore correcting to the reference temperature.5.3 When used in connection with bulk oil measurements,volume correction errors are minimized by observing thehydrometer reading at a temperature as close to referencetemperature as feasible.5.4 Gravity is a

25、factor governing the quality of crude oils.However, the gravity of a petroleum product is an uncertainindication of its quality. Correlated with other properties,gravity can be used to give approximate hydrocarbon compo-sition and heat of combustion.5.5 Gravity is an important quality indicator for

26、automotive,aviation and marine fuels, where it affects storage, handlingand combustion.6. Apparatus6.1 Hydrometers, of glass, graduated in degrees API aslisted in Table 1 and conforming to Specification E100.6.1.1 The user should ascertain that the instruments used forthis method conform to the requ

27、irements 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 themeniscus effect, the thermal g

28、lass 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 witha recognized calibration certificate, are classed as uncertified.6.2 Thermomet

29、ers, having a range from 5 to +215F andconforming to the requirements for Thermometer 12F asprescribed in Specification E1 or Thermometer 64F of theSpecification for IP Standard Thermometers.6.2.1 Alternate measuring devices or systems may be used,provided that the total uncertainty of the calibrate

30、d system is nogreater than when using liquid-in-glass thermometers. Thestated repeatability and reproducibility values are not appli-cable if alternate fluids are used in the liquid-in-glass thermom-eters.NOTE 2TheASTM Gravity Thermometer 12F has 0.5F subdivisionsand allowable 60.25F scale error.6.3

31、 Hydrometer Cylinder, clear glass, plastic, or metal (see6.3.1). The inside diameter of the cylinder shall be at least 25mm greater than the outside diameter of the hydrometer and theheight shall be such that the appropriate hydrometer floats inthe test portion with at least 25 mm clearance between

32、thebottom of the hydrometer and the bottom of the cylinder.6.3.1 Hydrometer cylinders constructed of plastic materialsshall be resistant to discoloration or attack by oil samples andshall not affect the material being tested.They shall not becomeopaque under prolonged exposure to sunlight.7. Tempera

33、ture of Test7.1 The gravity determined by the hydrometer method ismost accurate at or near the standard temperature of 60F5Available from ASTM International Headquarters. Order Adjunct No.ADJD1250. Original adjunct produced in 1983.TABLE 1 Available Hydrometers Scaled, Degrees APIDesignation TypeAPI

34、 Range, deg ScaleSeries Total Each Unit Division Error1H to 10H long plain 1 to 101 12 0.1 0.121H to 40H short plain 0 to 101 6 0.1 0.251H to 60H thermo 1 to 101 12 0.1 0.171H to 74H thermo 1 to 41 12 0.1 0.1Athermo 15 to 51 8AEight-degree range thermohydrometers are available.D287 12a2(15.56C). Use

35、 this or any other temperature between 0 and195F (18 and + 90C) for the test, so far as it is consistentwith the type of sample and necessary limiting conditionsshown in Table 2.8. Procedure8.1 For referee testing, use the long plain form of hydrom-eter (1H to 10H). For field testing, use the thermo

36、hydrometermethod in Test Method D6822/API MPMS Chapter 9.3.8.2 Adjust the temperature of the sample in accordance withTable 2. For field testing, test temperatures other than thoselisted in Table 2 may be used. The hydrometer cylinder shall beapproximately the same temperature as the sample to be te

37、sted.8.3 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 lowerboiling constituents of the more volatile samples. (WarningExtremely flammable. Vapors may cause flash fire.) For themor

38、e volatile samples, transfer to the hydrometer cylinder bysiphoning. (Do not start the siphon by mouth.) Use a rubberaspirator bulb. Remove any air bubbles formed, after they havecollected on the surface of the sample, by touching them witha piece of clean filter paper or other suitable means before

39、inserting the hydrometer. For field testing, make the gravitymeasurement directly in the sampling thief. Place the cylindercontaining the sample in a vertical position in a location freefrom air currents. Take precautions to prevent the temperatureof the sample from changing appreciably during the t

40、imenecessary to complete the test. During this period, the tempera-ture of the surrounding medium should not change more than5F (2C).8.4 Lower the hydrometer gently into the sample and, whenit has settled, depress it about two scale divisions into the liquidand then release it; keep the rest of the

41、stem dry, as unnecessaryliquid on the stem changes the effective weight of the instru-ment, and so affects the reading obtained. With samples of lowviscosity, a slight spin imparted to the instrument on releasingassists in bringing it to rest, floating freely away from the wallsof the hydrometer cyl

42、inder. Allow sufficient time for thehydrometer to become completely stationary and for all airbubbles to come to the surface. This is particularly necessary inthe case of the more viscous samples.8.5 When the hydrometer has come to rest, floating freely,and the temperature of the sample is constant

43、to 0.2F (0.1C),read the hydrometer to the nearest scale division. The correctreading is that point on the hydrometer scale at which thesurface of the liquid cuts the scale. Determine this point byplacing the eye slightly below the level of the liquid and slowlyraising it until the surface, first see

44、n as a distorted ellipse,appears to become a straight line cutting the hydrometer scale.8.6 To make a reading with nontransparent liquids, observethe point on the hydrometer scale to which the sample risesabove its main surface, placing the eye slightly above the planesurface of the liquid. This rea

45、ding requires a correction.Determine this correction for the particular hydrometer in useby observing the height above the main surface of the liquid towhich the sample rises on the hydrometer scale when thehydrometer in question is immersed in a transparent liquidhaving a surface tension similar to

46、 that of a sample under test.8.7 Observe the temperature of the sample to the nearest0.25F (0.1C) immediately before and after the observation ofthe gravity, the liquid in the cylinder being thoroughly butcautiously stirred with the thermometer (Note 3), and thewhole of the mercury thread being imme

47、rsed. Should thesetemperature readings differ by more than 1F (0.5C), repeatthe temperature and gravity observations when the temperatureof the sample has become more stable. Record the mean of thethermometer reading before and after the final hydrometerreading, to the nearest 1F, as the temperature

48、 of the test.NOTE 3When thermohydrometers are used, stir the sample by care-fully raising and lowering the hydrometer. It is satisfactory in this case toread the thermometer scale after the hydrometer reading has beenobserved. Read the thermometer to the nearest 1F (0.5C).9. Calculation9.1 Apply any

49、 relevant thermometer corrections to thetemperature reading observed in 8.3 and 8.7 and record theaverage of those two temperatures to the nearest 1F.9.2 Record the observed hydrometer scale readings to thenearest 0.1 API for transparent liquids.9.3 When gravities have been observed on opaque liquidsusing the procedure given in 8.6, subtract the meniscuscorrection from the hydrometer reading observed.NOTE 4The meniscus correction for a particular hydrometer in use isdetermined by observing the maximum height above the principal surfaceo