1、Designation: D6377 15Standard Test Method forDetermination of Vapor Pressure of Crude Oil:VPCRx(Expansion Method)1This standard is issued under the fixed designation D6377; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year o
2、f 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 use of automated vaporpressure instruments to determine the vapor pressure exerted inva
3、cuum of crude oils. This test method is suitable for testingsamples that exert a vapor pressure between 25 kPa and180 kPa at 37.8 C at vapor-liquid ratios from 4:1 to 0.02:1 (X= 4 to 0.02).NOTE 1This test method is suitable for the determination of the vaporpressure of crude oils at temperatures fro
4、m 0 C to 100 C and pressuresup to 500 kPa, but the precision and bias statements (see Section 14) maynot be applicable.1.2 This test method allows the determination of vaporpressure for crude oil samples having pour points above 0 C.1.3 The values stated in SI units are to be regarded asstandard. No
5、 other units of measurement are included in thisstandard.1.4 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-bili
6、ty of regulatory limitations prior to use. For specificwarning statements, see 7.2.1 7.3.2.2. Referenced Documents2.1 ASTM Standards:2D323 Test Method for Vapor Pressure of Petroleum Products(Reid Method)D2892 Test Method for Distillation of Crude Petroleum(15-Theoretical Plate Column)D3700 Practice
7、 for Obtaining LPG Samples Using a Float-ing Piston CylinderD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD5191 Test Method for Vapor Pressure of Petroleum Prod-ucts (Mini Method)D5853 Test Method for Pour
8、 Point of Crude OilsD6708 Practice for Statistical Assessment and Improvementof Expected Agreement Between Two Test Methods thatPurport to Measure the Same Property of a Material3. Terminology3.1 Definitions:3.1.1 platinum resistance thermometer, ntemperaturemeasuring device constructed with a lengt
9、h of platinum wire,whose electrical resistance changes in relation to temperature.3.1.2 vapor-liquid ratio (V/L), nthe ratio of the vaporvolume to the liquid volume of specimen, in equilibrium, underspecified conditions.3.2 Definitions of Terms Specific to This Standard:3.2.1 dead crude oil, ncrude
10、oil with sufficiently lowvapor pressure that, when exposed to normal atmosphericpressure at room temperature, does not result in boiling of thesample.3.2.1.1 DiscussionSampling and handling of dead crudeoils can usually be done without loss of sample integrity orother problems by using normal, non-p
11、ressurized samplecontainers such as cans.3.2.2 live crude oil, ncrude oil with sufficiently high vaporpressure that it would boil if exposed to normal atmosphericpressure at room temperature.3.2.2.1 DiscussionSampling and handling live crude oilsrequires a pressurized sample system and pressurized s
12、amplecontainers to ensure sample integrity and prevent loss ofvolatile components.3.2.3 Reid vapor pressure equivalent (RVPE), na valuecalculated by a defined correlation equation (see Eq X1.1) fromVPCR4at 37.8 C that is expected to be equivalent to the vaporpressure value obtained by Test Method D3
13、23.3.2.3.1 DiscussionAs noted in 14.3 and Appendix X1,subsection X1.2, since Eq X1.1 for estimating RVPE is notuniversally applicable to all crude oils, it is recommended toreport the VPCR4(38.7 C) result for a crude oil sample.1This test method is under the jurisdiction of ASTM Committee D02 onPetr
14、oleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.08 on Volatility.Current edition approved Oct. 1, 2015. Published October 2015. Originallyapproved in 1999. Last previous edition approved in 2014 as D6377 14. DOI:10.1520/D6377-15.2For referenced ASTM s
15、tandards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.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 Int
16、ernational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2.4 vapor pressure of crude oil (VPCRx),nthe pressureexerted in an evacuated chamber at a vapor-liquid ratio of X:1by conditioned or unconditioned crude oil, which may containgas, air or water, or a com
17、bination thereof, where X may varyfrom 4 to 0.02.3.3 Abbreviations:3.3.1 ARV, naccepted reference value3.3.2 RVPE, nReid vapor pressure equivalent3.3.3 V/L, nvapor liquid ratio3.3.4 VPCRx,nvapor pressure of crude oil at x vaporliquid ratio4. Summary of Test Method4.1 Employing a measuring chamber wi
18、th a built-in piston,a sample of known volume is drawn from the sample containerinto the temperature controlled chamber at 20 C or higher.After sealing the chamber, the volume is expanded by movingthe piston until the final volume produces the desired V/Lvalue. The temperature of the measuring chamb
19、er is thenregulated to the measuring temperature.4.2 After temperature and pressure equilibrium, the mea-sured pressure is recorded as the VPCRXof the sample. Thetest specimen shall be mixed during the measuring procedureby shaking the measuring chamber to achieve pressure equi-librium in a reasonab
20、le time of 5 min to 30 min.4.3 For results related to Test Method D323, the finalvolume of the measuring chamber shall be five times the testspecimen volume and the measuring temperature shall be37.8 C.5. Significance and Use5.1 Vapor pressure of crude oil at various V/Ls is animportant physical pro
21、perty for shipping and storage.NOTE 2A vapor-liquid ratio of 0.02:1 (X = 0.02) mimics closely thesituation of an oil tanker.5.2 Vapor pressure of crude oil is important to crude oilproducers and refiners for general handling and initial refinerytreatment.5.3 The vapor pressure determined by this tes
22、t method at avapor-liquid ratio of 4:1 (VPCR4) of crude oil at 37.8 C can berelated to the vapor pressure value determined on the samematerial when tested by Test Method D323 (see Appendix X1).5.4 Air saturation of crude oil shall not be done to avoidpotential vapor loss. However air saturation of t
23、he chilledverification fluid is mandatory (see 7.2 and Section 11).5.5 This test method can also be applied in online applica-tions.6. Apparatus6.1 The apparatus suitable for this test method employs asmall volume, cylindrically shaped measuring chamber withassociated equipment to control the chambe
24、r temperaturewithin the range from 0 C to 100 C. The measuring chambershall contain a movable piston with a minimum dead volume ofless than 1 % of the total volume at the lowest position to allowsample introduction into the measuring chamber and expansionto the desired V/L. A static pressure transdu
25、cer shall beincorporated in the piston. The measuring chamber shallcontain an inlet/outlet valve combination for sample introduc-tion and expulsion. The piston and the valve combination shallbe at the same temperature as the measuring chamber to avoidany condensation or excessive evaporation.6.1.1 T
26、he measuring chamber shall be designed to have atotal volume of 5 mL to 15 mL and shall be capable ofmaintaining a V/L of 4:1 to 0.02:1. The accuracy of theadjusted V/L shall be within 0.01.NOTE 3The measuring chambers employed by the instruments used ingenerating the precision and bias statements w
27、ere constructed of nickelplated aluminium, stainless steel and brass with a total volume of 5 mL.Measuring chambers exceedinga5mLcapacity and different design canbe used, but the precision and bias statement (see Section 14) may not beapplicable.6.1.2 The pressure transducer shall have a minimum ope
28、ra-tional range from 0 kPa to 500 kPa with a minimum resolutionof 0.1 kPa and a minimum accuracy of 60.5 kPa. The pressuremeasurement system shall include associated electronics andreadout devices to display the resulting pressure reading.6.1.3 Electronic temperature control shall be used to main-ta
29、in the measuring chamber at the prescribed temperaturewithin 60.1 C for the duration of the test.6.1.4 A platinum resistance thermometer shall be used formeasuring the temperature of the measuring chamber. Theminimum temperature range of the measuring device shall befrom 0 C to 100 C with a resoluti
30、on of 0.1 C and anaccuracy of 60.1 C.6.1.5 The vapor pressure apparatus shall have provisions forrinsing the measuring chamber with the next sample to betested or with a solvent of low vapor pressure.6.1.6 The vapor pressure apparatus shall have provisions forshaking the sample during the measuring
31、procedure with aminimum frequency of 1.5 cycles per second.6.2 Vacuum Pump for Calibration, capable of reducing thepressure in the measuring chamber to less than 0.01 kPaabsolute.6.3 McLeod Vacuum Gage or Calibrated Electronic VacuumMeasuring Device for Calibration, to cover at least the rangeof 0.0
32、1 kPa to 0.67 kPa. The calibration of the electronicmeasuring device shall be regularly verified in accordance withAnnex A of Test Method D2892.6.4 Pressure Measuring Device for Calibration, capable ofmeasuring local station pressure with an accuracy and aresolution of 0.1 kPa or better, at the same
33、 elevation relative tosea level as the apparatus in the laboratory.NOTE 4This standard does not give full details of instruments suitablefor carrying out this test. Details on the installation, operation andmaintenance of each instrument may be found in the manufacturersmanual.7. Reagents and Materi
34、als7.1 Purity of ReagentsUse chemicals of at least 99 %purity for verification of instrument performance (see Section11). Unless otherwise indicated, it is intended that all reagentsconform to the specifications of the Committee on AnalyticalD6377 152Reagents of the American Chemical Society where s
35、uchspecifications are available.3Other grades may be used, pro-vided it is first ascertained that the reagent is of sufficient purityto permit its use without lessening the accuracy of thedetermination.7.1.1 The chemicals in 7.2.1, 7.2.2, and 7.2.3 are suggestedfor verification of instrument perform
36、ance (see Section 11),based on the air saturated reference fuels analyzed in the TestMethod D5191 2003 interlaboratory study (ILS)4(see Table 1).Ptotused in Test Method D5191 is equivalent to VPCR4used inthis test method). Such reference fuels are not to be used forinstrument calibration. Table 1 id
37、entifies the accepted referencevalue (ARV) and uncertainty limits, as well as the acceptabletesting range for each of the reference fuels listed.7.1.2 The chemicals in 7.3.1 and 7.3.2 are suggested for useas rinsing solvents capable of cleaning the measuring chamber,the valves and the inlet and outl
38、et tubes.7.2 Verification Fluids:7.2.1 2,2-Dimethylbutane, (Warning2,2-dimethylbutaneis flammable and a health hazard.)7.2.2 2,3-Dimethylbutane, (Warning2,3-dimethylbutaneis flammable and a health hazard.)7.2.3 Pentane, (WarningPentane is flammable and ahealth hazard.)7.3 Solvents:7.3.1 Toluene, (Wa
39、rningToluene is flammable and ahealth hazard.)7.3.2 Acetone, (WarningAcetone is flammable and ahealth hazard.)8. Sampling and Sample Introduction8.1 General Requirements:8.1.1 The extreme sensitivity of vapor pressure measure-ments to losses through evaporation and the resulting changesin compositio
40、n requires the utmost precaution and the mostmeticulous care in the drawing and handling of samples.Sampling of live crude oil shall be performed in accordancewith Practice D3700. Sampling in accordance with PracticeD4057 shall only be used for dead crude oil and if PracticeD3700 is impractical.NOTE
41、 5Sampling in accordance with Practice D4177 may also beused instead of Practice D4057.8.1.2 For sampling in accordance with Practice D3700,afloating piston cylinder with a minimum sample volume of200 mL shall be used if the overall volume of the test specimenrequired for the vapor pressure determin
42、ation, including therinsing procedure is not larger than 20 mL. Larger floatingpiston cylinders can be used. The minimum piston back-pressure shall be higher than the sample vapor pressure at theintroduction temperature of the measuring chamber plus100 kPa for the shifting of the piston. The maximum
43、 back-pressure shall not exceed the maximum measurement pressureof the apparatus pressure transducer. Compressed air, or anyother, non-flammable compressed gas, can be used as theback-pressuring agent. The floating piston cylinder shall haveprovisions for mechanical stirring of the sample and a seco
44、ndvalve at the inlet for rinsing.8.1.3 Do not unnecessarily expose the samples to tempera-tures exceeding 30 C during sampling and storage. Forprolonged storage, store the samples in an appropriate room orrefrigerator.8.1.4 Perform the vapor pressure determination on the firsttest specimen withdrawn
45、 from the cylinder after the rinsingstep in 9.3. Do not use the remaining sample in the floatingpiston cylinder for more than three repeat vapor pressuredeterminations.8.1.5 In the case of quality control checks with purecompounds (see 11.1), smaller sample containers withoutapplied pressure can be
46、used.8.2 Sampling Procedures:8.2.1 If the sample is contained in a pressurized source likea pipeline, use a floating piston cylinder and obtain the sampledirectly from the source under pressure. Rinse the cylinder byopening the rinsing valve until the crude oil emerges at thesecond inlet. Close the
47、rinsing valve and let the piston moveslowly until at least 200 mL of sample has entered the cylinder.Close the inlet valve and apply the back pressure immediately.Check the filling of the cylinder to be at least 200 mL.NOTE 6The current precision statements were derived from the 2005ILS using sample
48、s in 250 mL floating piston cylinders (see 14.3).8.2.2 If the sample is taken from a non-pressurized sourcelike a storage tank, oil tanker, drum or other container, obtaina sample and test specimen in accordance with Practice D4057.Use either a 250 mL or 1 L sized container filled between 70 %and 80
49、 % with sample. For best testing precision(reproducibility), it is recommended that a 1 L sized containerbe used.NOTE 7The current precision statements were derived from the 2005ILS using samples in 1 L amber glass containers (see 14.3). However,samples in containers of other sizes, as prescribed in Practice D4057, may3Reagent 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 Labora
