ASTM D4052-2018a Standard Test Method for Density Relative Density and API Gravity of Liquids by Digital Density Meter.pdf

1、Designation: D4052 18aStandard Test Method forDensity, Relative Density, and API Gravity of Liquids byDigital Density Meter1This standard is issued under the fixed designation D4052; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,

2、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.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope*1.1 This test method co

3、vers the determination of the density,relative density, and API Gravity of petroleum distillates andviscous oils that can be handled in a normal fashion as liquidsat the temperature of test, utilizing either manual or automatedsample injection equipment. Its application is restricted toliquids with

4、total vapor pressures (see Test Method D5191)typically below 100 kPa and viscosities (see Test Method D445or D7042) typically below about 15 000 mm2/s at the tempera-ture of test. The total vapor pressure limitation however can beextended to 100 kPa provided that it is first ascertained thatno bubbl

5、es form in the U-tube, which can affect the densitydetermination. Some examples of products that may be testedby this procedure include: gasoline and gasoline-oxygenateblends, diesel, jet, basestocks, waxes, and lubricating oils.1.1.1 Waxes and highly viscous samples were not includedin the 1999 int

6、erlaboratory study (ILS) sample set that wasused to determine the current precision statements of themethod, since all samples evaluated at the time were analyzedat a test temperature of 15 C. Wax and highly viscous samplesrequire a temperature cell operated at elevated temperaturesnecessary to ensu

7、re a liquid test specimen is introduced foranalysis. Consult instrument manufacturer instructions forappropriate guidance and precautions when attempting toanalyze wax or highly viscous samples. Refer to the Precisionand Bias section of the method and Note 9 for more detailedinformation about the 19

8、99 ILS that was conducted.1.2 In cases of dispute, the referee method is the one wheresamples are introduced manually as in 6.2 or 6.3, as appropri-ate for sample type.1.3 When testing opaque samples, and when not usingequipment that is capable of automatic bubble detection,proper procedure shall be

9、 established so that the absence of airbubbles in the U-tube can be established with certainty. For thedetermination of density in crude oil samples use Test MethodD5002.1.4 The values stated in SI units are regarded as thestandard, unless stated otherwise. The accepted units of mea-sure for density

10、 are grams per millilitre (g/mL) or kilogramsper cubic metre (kg/m3).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, health, and environmental practices an

11、d deter-mine the applicability of regulatory limitations prior to use.For specific warning statements, see 3.2.1, Section 7, 9.1, 10.2,and Appendix X1.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decisi

12、on on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D287 Test Method for API Gravity of Crude Petroleum andPetroleum Products (Hydromet

13、er Method)D445 Test Method for Kinematic Viscosity of Transparentand Opaque Liquids (and Calculation of Dynamic Viscos-ity)D1193 Specification for Reagent WaterD1250 Guide for Use of the Petroleum Measurement TablesD1298 Test Method for Density, Relative Density, or APIGravity of Crude Petroleum and

14、 Liquid Petroleum Prod-ucts by Hydrometer MethodD4057 Practice for Manual Sampling of Petroleum andPetroleum Products1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.04.0D on Physi

15、cal and Chemical Methods.Current edition approved Dec. 15, 2018. Published February 2019. Originallyapproved in 1981. Last previous edition approved in 2018 as D4052 18. DOI:10.1520/D4052-18A.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at ser

16、viceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. Unit

17、ed StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers

18、 to Trade (TBT) Committee.1D4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD4377 Test Method for Water in Crude Oils by Potentiomet-ric Karl Fischer TitrationD5002 Test Method for Density, Relative Density, and APIGravity of Crude Oils by Digital Density AnalyzerD5191 Test Me

19、thod for Vapor Pressure of Petroleum Prod-ucts and Liquid Fuels (Mini Method)D7042 Test Method for Dynamic Viscosity and Density ofLiquids by Stabinger Viscometer (and the Calculation ofKinematic Viscosity)3. Terminology3.1 Definitions:3.1.1 density, nmass per unit volume at a specified tem-perature

20、3.1.1.1 DiscussionThe SI unit of density is kg/m3; the unitof measure g/cm3is commonly used in industry.3.1.2 relative density, nthe ratio of the density of amaterial at a stated temperature to the density of water at astated temperature.3.1.2.1 DiscussionRelative density is also commonlyknown as s

21、pecific gravity. Commonly used stated temperaturesare 20 C20 C, 15 C15 C, 20 C4 C and 60 F60 F.“Relative density” was historically known as the deprecatedterm “specific gravity.”3.2 Definitions of Terms Specific to This Standard:3.2.1 adjustment, vthe operation of bringing the instru-ment to a state

22、 of performance suitable for its use, by setting oradjusting the density meter constants.3.2.1.1 DiscussionOn some digital density analyzerinstruments, an adjustment may be made rather than calibratingthe instrument. The adjustment procedure uses air and freshlyboiled reagent water (WarningHandling

23、water at boiling ornear boiling temperature can present a safety hazard. Wearappropriate personal protective equipment.) as standards toestablish the linearity of measurements over a range ofoperating temperatures.3.2.2 API gravity, na special function of relative density60 F60 F, represented by:API

24、141.5relative density2 131.5 (1)3.2.2.1 DiscussionNo statement of reference temperatureis required since 60 F is included in the definition.3.2.3 calibration, vset of operations that establishes therelationship between the reference density of standards and thecorresponding density reading of the i

25、nstrument.3.2.4 sample aliquot, nthe fraction of the original labora-tory sample dedicated for this test.3.2.4.1 DiscussionThe sample aliquot is typically residingin syringes, sample vials, beakers, or containers for the purposeof transferring a representative test specimen into the appara-tus U-tub

26、e.3.2.5 test specimen, nthe volume of the sample aliquotresiding in the U-tube during the measurement cycle.3.2.5.1 DiscussionSample material residing in fillingnozzles, tubing and valve manifolds is not considered “TestSpecimen.” A test specimen can be measured only once.4. Summary of Test Method4.

27、1 A volume of approximately 1 mL to 2 mL of liquidsample is introduced into an oscillating U-tube and the changein oscillating frequency caused by the change in the mass of theU-tube is used in conjunction with calibration data to deter-mine the density, relative density, orAPI Gravity of the sample

28、Both manual and automated injection techniques are described.5. Significance and Use5.1 Density is a fundamental physical property that can beused in conjunction with other properties to characterize boththe light and heavy fractions of petroleum and petroleumproducts.5.2 Determination of the densi

29、ty or relative density ofpetroleum and its products is necessary for the conversion ofmeasured volumes to volumes at the standard temperature of15 C.6. Apparatus6.1 Digital Density AnalyzerA digital analyzer consistingof a U-shaped, oscillating tube, U-tube, and a system forelectronic excitation, fr

30、equency counting, and display. Theanalyzer shall accommodate the accurate measurement of thesample temperature during measurement or shall control andkeep the sample temperature constant to 60.05 C. The instru-ment shall be capable of meeting the precision requirementsdescribed in this test method.6

31、2 Syringes, for use primarily in manual injections, at least2 mL in volume with a tip or an adapter tip that will fit theopening of the U-tube.6.3 Flow-Through or Pressure Adapter, for use as an alter-native means of introducing the sample into the densityanalyzer either by a pump, by pressure, or

32、by vacuum.NOTE 1It is highly recommended that a vacuum not be applied tosamples prone to light-end loss, as it can easily lead to the formation ofbubbles in the U-tube. It is recommended to fabricate a special cap orstopper for sample containers so that air, such as from a squeeze pump, isused to di

33、splace a test specimen to the U-tube measuring cell by theflow-through method.6.4 Autosampler, required for use in automated injectionanalyses. The autosampler shall be designed to ensure theintegrity of the test specimen prior to and during the analysisand be equipped to transfer a representative p

34、ortion of samplealiquot to the digital density analyzer.6.5 Ultrasonic Bath, Unheated, (optional), of suitable di-mensions to hold container(s) placed inside of bath, for use ineffectively dissipating and removing air or gas bubbles thatmay be entrained in viscous sample types prior to analysis.7. R

35、eagents and Materials7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,D4052 18a2where such specifications

36、are available.3Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.7.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water as

37、definedby Type II of Specification D1193 or higher.7.3 Water, reagent water, freshly boiled to remove dissolvedgasses, for use as primary calibration standard. (WarningHandling water at boiling or near boiling temperature canpresent a safety hazard. Wear appropriate personal protectiveequipment.)7.4

38、 Cleaning Solvent, such as petroleum naphtha4(WarningPetroleum naphtha is extremely flammable), orother materials that are capable of flushing and removingsamples entirely from the U-tube.7.5 Acetone, for flushing and drying the U-tube.(WarningExtremely flammable.)7.6 Dry Air, for drying the U-tube.

39、8. Sampling, Test Specimens, and Test Units8.1 Sampling is defined as all the steps required to obtain analiquot of the contents of any pipe, tank, or other system, andto place the sample into the laboratory test container. Thelaboratory test container and sample volume shall be ofsufficient capacit

40、y to mix the sample and obtain a homoge-neous sample for analysis.8.2 Laboratory SampleUse only representative samplesobtained as specified in Practices D4057 or D4177 for this testmethod.8.3 Test SpecimenA portion or volume of sample aliquotobtained from the laboratory sample and delivered to thede

41、nsity analyzer U-tube. The test specimen is obtained asfollows:8.3.1 Mix the sample if required to homogenize, taking careto avoid the introduction of air bubbles. The mixing may beaccomplished as described in Practice D4177 or Test MethodD4377. Mixing at room temperature in an open container canres

42、ult in the loss of volatile material from certain sample types(for example, gasoline samples), so mixing in closed, pressur-ized containers or at least 10 C below ambient temperature isrequired for such sample types where loss of volatile materialis a potential concern. For some sample types, such a

43、s viscouslube oils that are prone to having entrained air or gas bubblespresent in the sample, the use of an ultrasonic bath (see 6.5)without the heater turned on (if so equipped), has been foundeffective in dissipating bubbles typically within 10 min.NOTE 2When mixing samples with volatile componen

44、ts, consider thesample properties in relation to both ambient temperature and pressure.8.3.2 For manual injections, draw the test specimen from aproperly mixed laboratory sample using an appropriate sy-ringe. If the proper density analyzer attachments and connect-ing tubes are used, as described in

45、6.3, then the test specimencan be delivered directly to the analyzers U-tube from themixing container. For automated injections, it is necessary tofirst transfer a portion of sample by appropriate means from aproperly mixed laboratory sample to the autosampler vials, andtake the necessary steps to e

46、nsure the integrity of the testspecimen prior to and during the analysis. Sample vials for theautosampler shall be sealed immediately after filling up to80 % 6 5 % and shall be kept closed until the auto samplertransfers the test specimen into the measuring cell. For highlyvolatile samples, cool the

47、 sample prior to measurement. Followthe manufacturers instructions.NOTE 3Overfilled sample vials can result in cross-contaminationbetween sample vials.9. Preparation of Apparatus9.1 Set up the density analyzer following the manufacturersinstructions. Set the internal temperature control so that thed

48、esired test temperature is established and maintained in theU-tube of the analyzer. Verify the instruments calibration atthe same temperature at which the density or relative density ofthe sample is to be measured or perform an adjustment (see3.2.1Discussion) in preparation of analyzing samples.(War

49、ningPrecise setting and control of the test temperaturein the U-tube is extremely important. An error of 0.1 C canresult in a change in density of one in the fourth decimal whenmeasuring in units of grams per millilitre.)10. Verification and Adjustment10.1 As a minimum requirement, calibration verification ofthe instrument is required when first set up and whenever thetest temperature is changed. Whenever the apparatus fails acalibration verification without discernible cause, the apparatusmust be adjusted. See 3.2.1.10.2 The adj