1、Designation: D5002 99 (Reapproved 2010)D5002 13Standard Test Method forDensity and Relative Density of Crude Oils by DigitalDensity Analyzer1This standard is issued under the fixed designation D5002; the number immediately following the designation indicates the year oforiginal adoption or, in the c
2、ase 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. Scope Scope*1.1 This test method covers the determination of the density or relative density of cr
3、ude oils that can be handled in a normalfashion as liquids at test temperatures between 15 and 35C. This test method applies to crude oils with high vapor pressuresprovided appropriate precautions are taken to prevent vapor loss during transfer of the sample to the density analyzer.1.2 This test met
4、hod was evaluated in round robin testing using crude oils in the 0.75 to 0.95 g/mL range. Lighter crude oil canrequire special handling to prevent vapor losses. Heavier crudes can require measurements at higher temperatures to eliminate airbubbles in the sample.1.3 The values stated in SI units are
5、to be regarded as standard. No other units of measurement are included in this standard.The accepted units of measurement of density are grams per millilitre and kilograms per cubic metre.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is
6、 the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. Specific warning statements are given in 7.4, 7.5, and 7.6.2. Referenced Documents2.1 ASTM Standards:2D941 Test Method for Densi
7、ty and Relative Density (Specific Gravity) of Liquids by Lipkin Bicapillary Pycnometer (Withdrawn1993)3D1193 Specification for Reagent WaterD1217 Test Method for Density and Relative Density (Specific Gravity) of Liquids by Bingham PycnometerD1250 Guide for Use of the Petroleum Measurement TablesD40
8、52 Test Method for Density, Relative Density, and API Gravity of Liquids by Digital Density MeterD4057 Practice for Manual Sampling of Petroleum and Petroleum ProductsD4177 Practice for Automatic Sampling of Petroleum and Petroleum ProductsD4377 Test Method for Water in Crude Oils by Potentiometric
9、Karl Fischer Titration3. Terminology3.1 Definitions:3.1.1 densitymass per unit volume at a specified temperature.3.1.2 relative densitythe ratio of the density of a material at a stated temperature to the density of water at a stated temperature.4. Summary of Test Method4.1 Approximately 0.7 mL 1 mL
10、 to 2 mL of crude oil sample is introduced into an oscillating sample tube and the change inoscillating frequency caused by the change in the mass of the tube is used in conjunction with calibration data to determine thedensity of the sample.1 This test method is under the jurisdiction of ASTM Commi
11、ttee D02 on Petroleum Products Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.04.0D on Physical and Chemical Methods.Current edition approved Sept. 15, 2010Oct. 1, 2013. Published November 2010October 2013. Originally approved in 1989. Last previous editio
12、n approved in 20052010as D500299(2005).D5002 99 (2010). DOI: 10.1520/D5002-99R10.10.1520/D5002-13.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Docum
13、ent Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becausei
14、t may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears a
15、t the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15. Significance and Use5.1 Density is a fundamental physical property that can be used in conjunction with other properties to characterize the qualityof crude
16、oils.5.2 The density or relative density of crude oils is used for the conversion of measured volumes to volumes at the standardtemperatures of 15C or 60F and for the conversion of crude mass measurements into volume units.5.3 The application of the density result obtained from this test method, for
17、 fiscal or custody transfer accounting calculations,can require measurements of the water and sediment contents obtained on similar specimens of the crude oil parcel.6. Apparatus6.1 Digital Density AnalyzerA digital analyzer consisting of a U-shaped, oscillating sample tube and a system for electron
18、icexcitation, frequency counting, and display. The analyzer must accommodate the accurate measurement of the sample temperatureduring measurement or must control the sample temperature as described in 6.2 and 6.5.The instrument shall be capable of meetingthe precision requirements described in Test
19、Method D4052.6.2 Circulating Constant-Temperature Bath, capable of maintaining the temperature of the circulating liquid constant to60.05C in the desired range. Temperature control can be maintained as part of the density analyzer instrument package.6.3 Syringes, at least 2 mL in volume with a tip o
20、r an adapter tip that will fit the inlet of the density analyzer.6.4 Flow-Through or Pressure Adapter, for use as an alternative means of introducing the sample into the density meter.6.5 Thermometer, calibrated and graduated to 0.1C, and a thermometer holder that can be attached to the instrument f
21、or settingand observing the test temperature. In calibrating the thermometer, the ice point and bore corrections should be estimated to thenearest 0.05C. Precise setting and control of the test temperature in the sample tube is extremely important. An error of 0.1Ccan result in a change in density o
22、f one in the fourth significant figure.7. Reagents and Materials7.1 Purity of ReagentsReagent grade chemicals shall be used in all tests. Unless otherwise indicated it is intended that allreagents shall conform to the specifications of the Committee on Analytical Reagents of the American Chemical So
23、ciety, wheresuch specifications are available.4 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently highpurity to permit its use without lessening the accuracy of the determination.7.2 Purity of WaterUnless otherwise indicated, references to water shall be
24、understood to mean reagent water as defined byType II of Specification D1193.7.3 Water, redistilled, freshly boiled and cooled reagent water for use as a primary calibration standard. (WarningHandlingwater at boiling or near boiling temperature can present a safety hazard. Wear appropriate personal
25、protective equipment.)7.4 Acetone, for flushing and drying the sample tube. (WarningExtremely flammable.)7.5 Petroleum Naphtha, for flushing viscous petroleum samples from the sample tube. (WarningExtremely flammable.)NOTE 1Suitable solvent naphthas are marketed under various designations such as “p
26、etroleum ether,” “ligroine,” or “precipitation naphtha.”7.6 n-Nonane, n-tridecane or cyclohexane, 99 % purity or better, or similar pure material for which the density is knownprecisely from literature references or by direct determination in accordance with Test Method D941 or D1217. (WarningExtrem
27、ely flammable.)8. Sampling, Test Specimens, and Test Units8.1 Sampling is defined as all the steps required to obtain an aliquot of the contents of any pipe, tank or other system, and toplace the sample into the laboratory test container. The laboratory test container and sample volume shall be of s
28、ufficientdimensions to allow mixing as described in 8.3.1. Mixing is required to obtain a homogeneous sample for analysis.8.2 Laboratory SampleUse only representative samples obtained as specified in Practices D4057 or D4177 for this testmethod.8.3 Test SpecimenThe aliquot of sample obtained from th
29、e laboratory sample and delivered to the density analyzer sampletube. The test specimen is obtained as follows:8.3.1 Mix the sample of crude oil to homogenize any sediment and water present.The mixing may be accomplished as describedin Practice D4177 or Test Method D4377. Mixing at room temperature
30、in an open container can result in the loss of light ends,so mixing in closed, pressurized containers or at sub-ambient temperatures is recommended.4 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For Suggestions on the testing of reagents not
31、 listed bythe American Chemical Society, see Annual Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.D5002 1328.3.2 Draw the test specimen from a properly mixed labor
32、atory sample using an appropriate syringe.Alternatively, if the properdensity analyzer attachments and connecting tubes are used then the test specimen can be delivered directly to the analyzerssample tube from the mixing container.9. Preparation of Apparatus9.1 Set up the density analyzer and const
33、ant temperature bath following the manufacturers instructions. Adjust the bath orinternal temperature control so that the desired test temperature is established and maintained in the sample compartment of theanalyzer. Calibrate the instrument at the same temperature at which the density of the samp
34、le is to be measured.10. Calibration of Apparatus10.1 Calibrate the instrument when first setting up and whenever the test temperature is changed. Thereafter, conduct calibrationchecks at least weekly during routine operation or more frequently as may be dictated by the nature of the crude oils bein
35、gmeasured (see 10.3).10.2 Initial calibration, or calibration after a change in test temperature, necessitates calculation of the values of the ConstantsA and B from the periods of oscillation, (T), observed when the sample cell contains certified reference liquids such as air anddouble-distilled re
36、-distilled freshly boiled water. (See Warning note in 7.3.) Other calibrating materials such as n-nonane,n-tridecane, cyclohexane, and n-hexadecane (for high temperature applications) can also be used as appropriate.10.2.1 While monitoring the oscillator period, T, flush the sample tube with petrole
37、um naphtha, followed with an acetone flushand dry with dry air. Continue drying until the display exhibits a steady reading. In cases where saline components can be depositedin the cell, flush with distilled water followed by acetone and dry air. Contaminated or humid air can affect the calibration.
38、 Whenthese conditions exist in the laboratory, pass the air used for calibration through a suitable purification and drying train. In addition,the inlet and outlet ports for the U-tube must be plugged during measurement of the calibration air to prevent ingress of moist air.10.2.2 Allow the dry air
39、in the U-tube to come to thermal equilibrium with the test temperature and record the T-value for air.10.2.3 Introduce about 0.7 mLof freshly boiled and cooled double-distilled a small volume (about 1 mLto 2 mL) of re-distilled,freshly boiled reagent water into the sample tube from the bottom openin
40、g using a suitable syringe. (See Warning note in 7.3.) Thewater must be free of even the smallest air or gas bubbles. The sample tube shall be completely full. Allow the water to reachthermal equilibrium at the test temperature and record the T-value for water and the test temperature.10.2.4 Alterna
41、tively introduce one of the hydrocarbon calibration standards and measure the T-value as in 10.2.3.10.2.5 Calculate the density of air at the temperature of test using the following equation:da 50.001293273/T#P/760#g/mL (1)where:T = temperature, K, andP = barometric pressure, torr.10.2.6 Determine t
42、he density of water at the temperature of test by reference to Table 1.10.2.7 Alternatively record the density at the test temperature for the hydrocarbon calibrant used in 10.2.4 as obtained from anappropriate reference source or from direct determination (see 7.6).10.2.8 Using the observed T-value
43、s and the reference values for water and air, calculate the values of the Constants A and Busing the following equations:A 5Tw22T a2#/dw 2da# (2)B 5Ta 22A 3da! (3)TABLE 1 Density of WaterA (in vacuo)Tempera-ture, CDensity,g/mLTempera-ture, CDensity,g/mLTempera-ture, CDensity,g/mL0.0 0.999840 21.0 0.
44、997991 40.0 0.9922123.0 0.999964 22.0 0.997769 45.0 0.9902084.0 0.999964 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 0.9
45、7483717.0 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 37.78 0.993042 100.0 0.958345A Densities conforming to the International Temperature Scale 1990 (ITS 90) wereextracted from Appendix G, Standard Methods for A
46、nalysis of Petroleum andRelated Products, 1991, Institute of Petroleum, London.D5002 133where:Tw = observed period of oscillation for cell containing water,Ta = observed period of oscillation for cell containing air,dw = density of water at test temperature, andda = density of air at test temperatur
47、e.Alternatively, use the T and d values for the other reference liquid if one is used.10.2.9 If the instrument is equipped to calculate density from the ConstantsAand B and the observed T-value from the sample,then enter the constants in the instrument memory in accordance with the manufacturers ins
48、tructions.10.2.10 Check the calibration and adjust if needed by performing the routine calibration check described in 10.3.10.2.11 To calibrate the instrument to determine relative density, that is, the density of the sample at a given temperature referredto the density of water at the same temperat
49、ure, follow 10.2.1 10.2.9, but substitute 1.000 for dw in performing the calculationsdescribed in 10.2.8.10.3 Since some crude oils can be difficult to remove from the sample tube, frequent calibration checks are recommended.Thesechecks and any subsequent adjustments to ConstantsAand B can be made if required, without repeating the calculation procedure.NOTE 2The need for a change in calibration is generally attributable to deposits in the sample tube that are not removed by the routine flushingprocedure. Although this condition can be compensat
