1、Designation: D 4052 96 (Reapproved 2002)e1Designation: 365/84(86)An American National StandardStandard Test Method forDensity and Relative Density of Liquids by Digital DensityMeter1This standard is issued under the fixed designation D 4052; the number immediately following the designation indicates
2、 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 last revision or reapproval.This method was adopted as a joint ASTM-IP standard in 198
3、4.This standard has been approved for use by agencies of the Department of Defense.e1NOTEWarning notes were placed in the text editorially in May 2002.1. Scope1.1 This test method covers the determination of the densityor relative density of petroleum distillates and viscous oils thatcan be handled
4、in a normal fashion as liquids at test tempera-tures between 15 and 35C. Its application is restricted toliquids with vapor pressures below 600 mm Hg (80 kPa) andviscosities below about 15 000 cSt (mm2/s) at the temperatureof test.1.2 This test method should not be applied to samples sodark in color
5、 that the absence of air bubbles in the sample cellcannot be established with certainty. For the determination ofdensity in crude oil samples use Test Method D 5002.1.3 The accepted units of measure for density are grams permillilitre or kilograms per cubic metre.1.4 This standard does not purport t
6、o 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-bility of regulatory limitations prior to use. For specific hazardstatements, see 7.4, 7.5, and 9
7、.1.2. Referenced Documents2.1 ASTM Standards:D 1193 Specification for Reagent Water2D 1250 Guide for Petroleum Measurement Tables3D 4057 Practice for Manual Sampling of Petroleum andPetroleum Products4D 4177 Practice for Automatic Sampling of Petroleum andPetroleum Products4D 4377 Test Method for Wa
8、ter in Crude Oils by Potentio-metric Karl Fischer Titration4D 5002 Test Method for Density and Relative Density ofCrude Oils by Digital Density Analyzer43. Terminology3.1 Definitions:3.1.1 densitymass per unit volume at a specified tempera-ture.3.1.2 relative densitythe ratio of the density of a mat
9、erialat a stated temperature to the density of water at a statedtemperature.4. Summary of Test Method4.1 A small volume (approximately 0.7 mL) of liquidsample is introduced into an oscillating sample tube and thechange in oscillating frequency caused by the change in themass of the tube is used in c
10、onjunction with calibration data todetermine the density of the sample.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
11、the density or relative density ofpetroleum and its products is necessary for the conversion ofmeasured volumes to volumes at the standard temperature of15C.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of Subco
12、mmitteeD02.04.0D on Physical and Chemical Methods.Current edition approved Apr. 10, 1996. Published June 1996. Originallypublished as D 4052 81. Last previous edition D 4052 95.2Annual Book of ASTM Standards, Vol 11.01.3Annual Book of ASTM Standards, Vol 05.01.4Annual Book of ASTM Standards, Vol 05.
13、02.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6. Apparatus6.1 Digital Density AnalyzerA digital analyzer consistingof a U-shaped, oscillating sample tube and a system forelectronic excitation, frequency counting, and display. Th
14、eanalyzer must accommodate the accurate measurement of thesample temperature during measurement or must control thesample temperature as described in 6.2. The instrument shall becapable of meeting the precision requirements described in thistest method.6.2 Circulating Constant-Temperature Bath, (opt
15、ional) ca-pable of maintaining the temperature of the circulating liquidconstant to 60.05C in the desired range. Temperature controlcan be maintained as part of the density analyzer instrumentpackage.6.3 Syringes, at least 2 mL in volume with a tip or anadapter tip that will fit the opening of the o
16、scillating tube.6.4 Flow-Through or Pressure Adapter, for use as analternative means of introducing the sample into the densityanalyzer either by a pump or by vacuum.6.5 Thermometer, calibrated and graduated to 0.1C, and athermometer holder that can be attached to the instrument forsetting and obser
17、ving the test temperature. In calibrating thethermometer, the ice point and bore connections should beestimated to the nearest 0.05C.7. Reagents and Materials7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall con
18、form to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.5Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of th
19、e determination.7.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water as definedby Type II of Specification D 1193.7.3 Water, redistilled, freshly boiled and cooled reagentwater for use as a primary calibration standard.7.4 Petroleum Naphtha6for
20、flushing viscous petroleumsamples from the sample tube. (WarningExtremely flam-mable.)7.5 Acetone, for flushing and drying the sample tube.(WarningExtremely flammable.)7.6 Dry Airfor blowing the oscillator tube.8. Sampling, Test Specimens, and Test Units8.1 Sampling is defined as all the steps requi
21、red 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 capacity to mix the sample and obtain a homoge-neous sample for analysis.8.2 Laboratory SampleUs
22、e only representative samplesobtained as specified in Practices D 4057 or D 4177 for this testmethod.8.3 Test SpecimenAportion or volume of sample obtainedfrom the laboratory sample and delivered to the densityanalyzer sample tube. The test specimen is obtained as follows:8.3.1 Mix the sample if req
23、uired to homogenize. The mixingmay be accomplished as described in Practice D 4177 (Section11) or Test Method D 4377 (A.1). Mixing at room temperaturein an open container can result in the loss of volatile material,so mixing in closed, pressurized containers or at sub-ambienttemperatures is recommen
24、ded.8.3.2 Draw the test specimen from a properly mixed labo-ratory sample using an appropriate syringe.Alternatively, if theproper density analyzer attachments and connecting tubes areused then the test specimen can be delivered directly to theanalyzers sample tube from the mixing container.9. Prepa
25、ration of Apparatus9.1 Set up the density analyzer and constant temperaturebath following the manufacturers instructions. Adjust the bathor internal temperature control so that the desired test tempera-ture is established and maintained in the sample compartmentof the analyzer. Calibrate the instrum
26、ent at the same tempera-ture at which the density of the sample is to be measured.(WarningPrecise setting and control of the test temperaturein the sample tube is extremely important. An error of 0.1Ccan result in a change in density of one in the fourth decimal.)10. Calibration of Apparatus10.1 Cal
27、ibrate the instrument when first set up and when-ever the test temperature is changed. Thereafter, conductcalibration checks at weekly intervals during routine operation.10.2 Initial calibration, or calibration after a change in testtemperature, necessitates calculation of the values of theconstants
28、 A and B from the periods of oscillation (T) observedwhen the sample cell contains air and redistilled, freshly boiledand cooled reagent water. Other calibrating materials such asn-nonane, n-tridecane, cyclohexane, and n-hexadecane (forhigh temperature applications) can also be used as appropriate.1
29、0.2.1 While monitoring the oscillator period, T, flush thesample tube with petroleum naphtha, followed with an acetoneflush and dry with dry air. Contaminated or humid air can affectthe calibration. When these conditions exist in the laboratory,pass the air used for calibration through a suitable pu
30、rificationand drying train. In addition, the inlet and outlet ports for theU-tube must be plugged during measurement of the calibrationair to prevent ingress of moist air.10.2.2 Allow the dry air in the U-tube to come to thermalequilibrium with the test temperature and record the T-valuefor air.10.2
31、.3 Introduce a small volume (about 0.7 mL) of redis-tilled, freshly boiled and cooled reagent water into the sampletube from the bottom opening using a suitable syringe. The testportion must be homogeneous and free of even the smallest airor gas bubbles. The sample tube does not have to be completel
32、y5Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacop
33、eiaand National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.6Suitable solvent naphthas are marketed under various designations such as“Petroleum Ether,” “Ligroine,” or “Precipitation Naphtha.”D 4052 96 (2002)e12full as long as the liquid meniscus is beyond the suspensionpoin
34、t. Allow the display to reach a steady reading and recordthe T-value for water.10.2.4 Calculate the density of air at the temperature of testusing the following equation:da, g/mL 5 0.001293273.15/T#P/760 (1)where:T = temperature, K, andP = barometric pressure, torr.10.2.5 Determine the density of wa
35、ter at the temperature oftest by reference to Table 1.10.2.6 Using the observed T-values and the reference valuesfor water and air, calculate the values of the Constants A and Busing the following equations:A 5 Tw2 Ta2#/dw da# (2)B 5 Ta2 A 3 da! (3)Tw= observed period of oscillation for cell contain
36、ingwater,Ta= observed period of oscillation for cell containing air,dw= density of water at test temperature, andda= density of air at test temperature.Alternatively, use the T and d values for the other referenceliquid if one is used.10.2.7 If the instrument is equipped to calculate densityfrom the
37、 constants A and B and the observed T-value from thesample, then enter the constants in the instrument memory inaccordance with the manufacturers instructions.10.2.8 Check the calibration and adjust if needed by per-forming the routine calibration check described in 10.3.10.2.9 To calibrate the inst
38、rument to display relative den-sity, that is, the density of the sample at a given temperaturereferred to the density of water at the same temperature, follow10.2.1-10.2.7, but substitute 1.000 for dwin performing thecalculations described in 10.2.6.10.3 Weekly calibration adjustments to constants A
39、 and Bcan be made if required, without repeating the calculationprocedure. The need for a change in calibration is generallyattributable to deposits in the sample tube that are not removedby the routine flushing procedure. Although this condition canbe compensated for by adjusting A and B, it is goo
40、d practice toclean the tube with warm chromic acid solution (WarningCauses severe burns. A recognized carcinogen.) whenever amajor adjustment is required. Chromic acid solution is the mosteffective cleaning agent; however, surfactant cleaning fluidshave also been used successfully.10.3.1 Flush and d
41、ry the sample tube as described in 10.2.1and allow the display to reach a steady reading. If the displaydoes not exhibit the correct density for air at the temperature oftest, repeat the cleaning procedure or adjust the value ofconstant B commencing with the last decimal place until thecorrect densi
42、ty is displayed.10.3.2 If adjustment to constant B was necessary in 10.3.1then continue the recalibration by introducing redistilled,freshly boiled and cooled reagent water into the sample tube asdescribed in 10.2.3 and allow the display to reach a steadyreading. If the instrument has been calibrate
43、d to display thedensity, adjust the reading to the correct value for water at thetest temperature (Table 1) by changing the value of constant A,commencing with the last decimal place. If the instrument hasbeen calibrated to display the relative density, adjust thereading to the value 1.0000.NOTE 1In
44、 applying this weekly calibration procedure, it can be foundthat more than one value each for A and B, differing in the fourth decimalplace, will yield the correct density reading for the density of air andwater. The setting chosen would then be dependent upon whether it wasapproached from a higher
45、or lower value. The setting selected by thismethod could have the effect of altering the fourth place of the readingobtained for a sample.10.4 Some analyzer models are designed to display themeasured period of oscillation only (T-values) and theircalibration requires the determination of an instrume
46、nt constantK, which must be used to calculate the density or relativedensity from the observed data.10.4.1 Flush and dry the sample tube as described in 10.2.1and allow the display to reach a steady reading. Record theT-value for air.10.4.2 Introduce redistilled, freshly boiled and cooled re-agent w
47、ater into the sample tube as described in 10.2.3, allowthe display to reach a steady reading and record the T-value forwater.10.4.3 Using the observed T-values and the reference valuesfor water and air (10.2.4 and 10.2.5), calculate the instrumentconstant K using the following equations:For density:
48、K15 dw da#/Tw2 Ta2# (4)For relative density:K25 1.0000 da#/Tw2 Ta2# (5)where:Tw= observed period of oscillation for cell containingwater,Ta= observed period of oscillation for cell containing air,dw= density of water at test temperature, andda= density of air at test temperature.TABLE 1 Density of W
49、aterATemperature,CDensity,g/mLTemperature,CDensity,g/mLTemperature,CDensity,g/mL0.0 0.999840 21.0 0.997991 40.0 0.9922123.0 0.999964 22.0 0.997769 45.0 0.9902084.0 0.999972 23.0 0.997537 50.0 0.9880305.0 0.999964 24.0 0.997295 55.0 0.98568810.0 0.999699 25.0 0.997043 60.0 0.98319115.0 0.999099 26.0 0.996782 65.0 0.98054615.56 0.999012 27.0 0.996511 70.0 0.97775916.0 0.998943 28.0 0.996231 75.0 0.97483717.0 0.998774 29.0 0.995943 80.0 0.97178518.0 0.998595 30.0 0.995645 85.0 0.96860619.0 0.998404 35.0 0.994029 90.0 0.96530520.0 0.998203 37.7
