1、Designation: D5002 13D5002 15Standard 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 case of revision, t
2、he 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*1.1 This test method covers the determination of the density or relative density of crude oils that can be han
3、dled in a normalfashion as liquids at test temperatures between 1515 C and 35C.35 C. This test method applies to crude oils with high vaporpressures provided appropriate precautions are taken to prevent vapor loss during transfer of the sample to the density analyzer.1.2 This test method was evaluat
4、ed in round robin testing using crude oils in the 0.750.75 gmL to 0.950.95 g g/mL mL range.Lighter crude oil can require special handling to prevent vapor losses. Heavier crudes can require measurements at highertemperatures to eliminate air bubbles in the sample.1.3 The values stated in SI units ar
5、e 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
6、is 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 Den
7、sity 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 TablesD
8、4052 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 Potentiometri
9、c 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 1 mL to 2
10、 mL of crude oil sample is introduced into an oscillating sample tube and the change in oscillatingfrequency caused by the change in the mass of the tube is used in conjunction with calibration data to determine the density ofthe sample.1 This test method is under the jurisdiction ofASTM Committee D
11、02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of SubcommitteeD02.04.0D on Physical and Chemical Methods.Current edition approved Oct. 1, 2013Dec. 15, 2015. Published October 2013February 2016. Originally approved in 1989. Last previous edition approved in 20
12、102013as D5002 99 (2010).D5002 13. DOI: 10.1520/D5002-13.10.1520/D5002-15.2 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 Document Summary page on the
13、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. Becauseit may not be technically
14、 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 at the end of this standa
15、rdCopyright 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 oils.5.2 The density or
16、relative density of crude oils is used for the conversion of measured volumes to volumes at the standardtemperatures of 15C15 C or 60F60 F 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 fiscal or custo
17、dy 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 electronicexcitation, fr
18、equency 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 Method D4052.6.2
19、 Circulating Constant-Temperature Bath, capable of maintaining the temperature of the circulating liquid constant to60.05C60.05 C in the desired range. Temperature control can be maintained as part of the density analyzer instrument package.6.3 Syringes, at least 2 mL 2 mL in volume with a tip or an
20、 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,0.1 C, and a thermometer holder that can be attached to the instrument
21、 forsetting and observing the test temperature. In calibrating the thermometer, the ice point and bore corrections should be estimatedto the nearest 0.05C.0.05 C. Precise setting and control of the test temperature in the sample tube is extremely important.An errorof 0.1C0.1 C can result in a change
22、 in density of 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 America
23、n Chemical Society, 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 wa
24、ter shall be understood to mean reagent water as defined byType II of Specification D1193. or better.7.3 Water, redistilled, freshly boiled reagent water reagent water, freshly boiled, to remove dissolved gasses, for use as a primarycalibration standard. (WarningHandling water at boiling or near boi
25、ling temperature can present a safety hazard. Wearappropriate personal 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 1Suita
26、ble solvent naphthas are marketed under various designations such as “petroleum 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 det
27、ermination in accordance with Test Method D941 or D1217. (WarningExtremely 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 c
28、ontainer. The laboratory test container and sample volume shall be of sufficientdimensions 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
29、this testmethod.8.3 Test SpecimenThe aliquot of sample obtained from the 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 descr
30、ibedin Practice D4177 or Test Method D4377. Mixing at room temperature 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
31、Society, Washington, DC. For Suggestions on the testing of reagents not 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), Rockvill
32、e, MD.D5002 1528.3.2 Draw the test specimen from a properly mixed laboratory 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 contain
33、er.9. Preparation of Apparatus9.1 Set up the density analyzer and constant 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
34、the instrument at the same temperature at which the density of the sample 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
35、more frequently as may be dictated by the nature of the crude oils beingmeasured (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
36、contains certified reference liquids such as air andre-distilled freshly boiled reagent 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 monitorin
37、g the oscillator period, T, flush the sample tube with petroleum 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
38、dry air. Contaminated or humid air can affect the calibration. 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
39、 air to prevent ingress of moist air.10.2.2 Allow the dry air in the U-tube to come to thermal equilibrium with the test temperature and record the T-value for air.10.2.3 Introduce a small volume (aboutvolume, about 1 mL to 2 mL)2 mL, of re-distilled, freshly boiled reagent water into thesample tube
40、 using a suitable syringe. (See Warning note in 7.3.) The water must be free of even the smallest air or gas bubbles.The sample tube shall be completely full. Allow the water to reach thermal equilibrium at the test temperature and record theT-value for water and the test temperature.10.2.4 Alternat
41、ively 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)da 50.001293273.15/T#P/101.325#g/mL (1)where:T = temperature, K, andP = barome
42、tric pressure, torr.P = barometric pressure, kPa.10.2.6 Determine the 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 fr
43、om direct determination (see 7.6).10.2.8 Using the observed T-values 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)where:Tw = observed period of oscillation for cell containing water,Ta
44、 = observed period of oscillation for cell containing air,dw = density of water at test temperature, andda = density of air at test temperature.Tw = observed period of oscillation for cell containing water, s,Ta = observed period of oscillation for cell containing air, s,dw = density of water at tes
45、t temperature, g/mL, andda = density of air at test temperature, g/mL.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 constan
46、ts in the instrument memory in accordance with the manufacturers instructions.10.2.10 Check the calibration and adjust if needed by performing the routine calibration check described in 10.3.D5002 15310.2.11 To calibrate the instrument to determine relative density, that is, the density of the sampl
47、e at a given temperature referredto the density of water at the same temperature, 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 recommende
48、d.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 thi
49、s condition can be compensated for by adjusting A and B, as described below, it is good practice to clean the tube with warmchromic acid solution (WarningCauses severe burns. A recognized carcinogen.) whenever a major adjustment is required. Chromic acid solution isthe most effective cleaning agent; however, surfactant-type cleaning fluids have also been used successfully.10.3.1 Flush and dry the sample tube as described in 10.2.1 and allow the display to reach a steady reading. If the display doesnot exhibit the correct T-value or
