1、Designation: D 6377 03An American National StandardStandard Test Method forDetermination of Vapor Pressure of Crude Oil:VPCRx(Expansion Method)1This standard is issued under the fixed designation D 6377; the number immediately following the designation indicates the year oforiginal adoption or, in t
2、he 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.1. Scope*1.1 This test method covers the use of automated vaporpressure instruments to determine
3、 the vapor pressure of crudeoils at temperatures between 5 and 80C for vapor-liquid ratiosfrom 4:1 to 0.02:1 (X=4to0.02) and pressures from 7 to 500kPa (1.0 to 70 psi).1.2 The values stated in SI units are regarded as standard.The inch-pound units given in parentheses are provided forinformation onl
4、y.1.3 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-bility of regulatory limitations prior to use.2. Referenced
5、 Documents2.1 ASTM Standards:2D 323 Test Method for Vapor Pressure of Petroleum Prod-ucts (REID Method)D 2892 Test Method for Distillation of Crude Petroleum(15-Theoretical Plate Column)D 3700 Practice for Obtaining LPG Samples Using a Float-ing Piston CylinderD 4057 Practice for Manual Sampling of
6、Petroleum andPetroleum ProductsD 4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD 5191 Test Method for Vapor Pressure of Petroleum Prod-ucts (Mini Method)D 5853 Test Method for Pour Point of Crude Oils3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 dead
7、 crude oila term usually employed for crudeoils that, when exposed to normal atmospheric pressure atroom temperature, will not result in actual boiling of thesample.3.1.1.1 DiscussionSampling and handling of dead crudeoils can usually be done without problems in normal samplecontainers, such as cans
8、 and so forth. The use of pressurecylinders for (sub)sampling and sample storage is a necessaryand mandatory requirement in this test method for live crudeoils and, to prevent the loss of volatile material and preserveprecision, is strongly recommended for dead crude oils as well.3.1.2 live crude oi
9、la term usually employed for crude oilscontained in pressurized systems that, when brought to normalatmospheric pressure at room temperature, will result in actualboiling of the sample.3.1.2.1 DiscussionSampling and handling of samples oflive crude oils will necessitate the use of pressure cylinders
10、 andpreclude the use of normal sample containers, such as cans andso forth.3.1.3 Reid vapor pressure equivalent (RVPE)a value cal-culated by a correlation equation (see 14.3 and Appendix X1)from VPCR4, which is related to the value obtained on thesample by Test Method D 323.3.1.4 vapor-liquid ratio
11、(V/L), nthe ratio of the vaporvolume to the liquid specimen volume.3.1.4.1 DiscussionThe total measuring chamber volumeis the sum of the vapor volume and the liquid specimenvolume.3.1.5 vapor pressure of crude oil (VPCRx), nthe pressureexerted in an evacuated chamber at a vapor-liquid ratio of X:1by
12、 conditioned or unconditioned crude oil, which may containgas, air or water, or a combination thereof, where X may varyfrom 4 to 0.02.4. Summary of Test Method4.1 Employing a measuring chamber with a built-in piston,a sample of known volume is drawn from a pressurizedsampling system (floating piston
13、 cylinder) into the temperature1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.08 on Volatility.Current edition approved Dec. 1, 2003. Published January 2004. Originallyapproved in 1999. Last pr
14、evious edition approved in 1999 as D 6377 99.2For referenced ASTM standards, 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.1*A Summary of C
15、hanges section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.controlled chamber at 20C or higher. After sealing thechamber, the volume is expanded by moving the piston untilthe final volume produc
16、es the desired V/L value. The tempera-ture of the measuring chamber is then regulated to themeasuring temperature.4.2 After temperature and pressure equilibrium, the mea-sured pressure is recorded as the VPCRxof the sample. The testspecimen shall be mixed during the measuring procedure byshaking the
17、 measuring chamber to achieve pressure equilib-rium in a reasonable time between 5 and 30 min.4.3 For results related to Test Method D 323, the finalvolume of the measuring chamber shall be five times the testspecimen volume and the measuring temperature shall be37.8C.5. Significance and Use5.1 Vapo
18、r pressure of crude oil at various V/Ls is animportant physical property for shipping and storage.5.2 Vapor pressure of crude oil is important to crude oilproducers and refiners for general handling and initial refinerytreatment.NOTE 1AV/L of 0.02:1 (X = 0.02) mimics closely the situation of anoil t
19、anker.5.3 To prevent losses of high volatile compounds, thesample is always maintained at a pressure at least 100 kPa(14.5 psi) higher than the vapor pressure.5.4 The vapor pressure determined by this test method at aV/L of 4:1 (VPCR4) of crude oil at 37.8C can be related to thevapor pressure value
20、determined on the same material whentested by Test Method D 323 (see Appendix X1).5.5 Chilling and air saturation of the sample prior to thevapor pressure measurement is not required.5.6 This test method allows the determination of VPCRxsamples having pour points above 0C.6. Apparatus6.1 The apparat
21、us suitable for this test method employs asmall volume, cylindrically shaped measuring chamber withassociated equipment to control the chamber temperaturewithin the range from 5 to 80C. The measuring chamber shallcontain a movable piston with a minimum dead volume of lessthan 1 % of the total volume
22、 at the lowest position to allowsample introduction into the measuring chamber and expansionto the desired V/L. A static pressure transducer shall beincorporated in the piston. The measuring chamber shallcontain an inlet/outlet valve combination for sample introduc-tion and expulsion. The piston and
23、 the valve combination shallbe at the same temperature as the measuring chamber to avoidany condensation or excessive evaporation.36.1.1 The measuring chamber shall be designed to have atotal volume of 5 to 15 mL and shall be capable of maintaininga V/L of 4:1 to 0.02:1. The accuracy of the adjusted
24、 V/L shallbe within 0.01.NOTE 2The measuring chambers employed by the instruments usedin generating the precision and bias statements were constructed of nickelplated aluminum and stainless steel with a total volume of 5 mL.Measuring chambers exceedinga5mLcapacity and having a differentdesign can be
25、 used, but the precision and bias statements (see Section 14)are not known to apply.6.1.2 The pressure transducer shall have a minimum opera-tional range from 0 to 500 kPa (0 to 72.5 psi) with a minimumresolution of 0.1 kPa (0.01 psi) and a minimum accuracy of60.5 kPa (60.07 psi). The pressure measu
26、rement system shallinclude associated electronics and readout devices to displaythe resulting pressure reading.6.1.3 Electronic temperature control shall be used to main-tain the measuring chamber at the prescribed temperaturewithin 60.1C for the duration of the test.6.1.4 A platinum resistance ther
27、mometer shall be used formeasuring the temperature of the measuring chamber. Theminimum temperature range of the measuring device shall befrom 0 to 100C with a resolution of 0.1C and an accuracy of60.1C.6.1.5 The vapor pressure apparatus shall have provisions forrinsing the measuring chamber with th
28、e 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 procedure with aminimum frequency of 1.5 cycles per second.6.2 Vacuum Pump for Calibration, capable of reducing thepressure in the mea
29、suring chamber to less than 0.01 kPa (0.001psi) absolute.6.3 McLeod Vacuum Gage or Calibrated Electronic VacuumMeasuring Device for Calibration, to cover at least the rangefrom 0.01 to 0.67 kPa (0.1 to 5 mm Hg). The calibration of theelectronic vacuum measuring device shall be regularly verifiedin a
30、ccordance with Annex A6.3 of Test Method D 2892.6.4 Pressure Measuring Device for Calibration, capable ofmeasuring local station pressure with an accuracy and aresolution of 0.1 kPa (1 mm Hg) or better, at the same elevationrelative to sea level as the apparatus in the laboratory.NOTE 3This test met
31、hod does not give full details of instrumentssuitable for carrying out this test. Details on the installation, operation, andmaintenance of each instrument may be found in the manufacturersmanual.7. Reagents and Materials7.1 Purity of ReagentsUse chemicals of at least 99 %purity for quality control
32、checks (see Section 11). Unlessotherwise indicated, it is intended that all reagents conform tothe specifications of the Committee on Analytical Reagents ofthe American Chemical Society4where such specifications areavailable. Other grades may be used, provided it is firstascertained that the reagent
33、 is of sufficient high purity to permitits use without lessening the accuracy of the determination.NOTE 4The chemicals in this section are suggested for cleaning and3Vapor pressure apparatus meeting these requirements are available fromGrabner Instruments, A-1220 Vienna, Dr. Neurathgasse 1, Austria.
34、4Reagent 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
35、eiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.D6377032quality control procedures (see Section 11) and are not used for instrumentcalibration. (Warning2,2dimethylbutane, 2,3-dimethylbutane, toluene,pentane, methanol, and acetone are flammable and health hazards.)
36、7.2 Cleaning SolventsUse suitable solvents capable ofcleaning the measuring chamber, the valves, and the inlet andoutlet tubes. Two commonly used solvents are toluene andacetone.8. Sampling and Sample Introduction8.1 General Requirements:8.1.1 The extreme sensitivity of vapor pressure measure-ments
37、to losses through evaporation and the resulting changesin composition 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 D 3700. Sampling in accordance with PracticeD 4057 shall on
38、ly be used for dead crude oil and if PracticeD 3700 is impractical.NOTE 5Sampling in accordance with Practice D 4177 may also beused instead of Practice D 4057.8.1.2 A floating piston cylinder with a minimum samplevolume of 200 mL shall be used if the overall volume of thetest specimen required for
39、the vapor pressure determination,including the rinsing procedure, is not larger than 20 mL.Larger floating piston cylinders can be used. The minimumpiston back-pressure shall be higher than the sample vaporpressure at the introduction temperature of the measuringchamber plus 100 kPa (15 psi) for the
40、 shifting of the piston.The maximum back-pressure shall not exceed the maximummeasurement pressure of the apparatus pressure transducer.Compressed air, or any other compressed gas, can be used asthe back-pressuring agent. The floating piston cylinder shallhave provisions for mechanical stirring of t
41、he sample and asecond valve at the inlet for rinsing.NOTE 6The present precision statement was derived using samples in250mL floating piston cylinders.8.1.3 Do not unnecessarily expose the samples to tempera-tures exceeding 30C during sampling and storage. For pro-longed storage, store the samples i
42、n an appropriate room orrefrigerator.8.1.4 Perform the vapor pressure determination on the firsttest specimen withdrawn 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
43、case of quality control checks with purecompounds (see 11.1), smaller sample containers withoutapplied pressure can be 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 un
44、der pressure. Rinse the cylinder byopening the rinsing valve until the crude oil emerges at thesecond inlet. Close the 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 fillin
45、g of the cylinder to be at least 200 mL.8.2.2 If the sample is taken from a nonpressurized sourcelike a storage tank, oil tanker, drum, or other small container,obtain the sample in accordance with Practice D 4057 and fillthe sample into an open floating piston cylinder at ambientpressure. Close the
46、 floating piston cylinder, and apply theback-pressure immediately after the cylinder is filled with thesample. Turn the cylinder in a vertical position so that the inletis on top, and open the inlet valve of the cylinder until thecrude oil emerges at the inlet to discharge the captured air.Close the
47、 valve, and check the filling of the cylinder to be atleast 200 mL.8.3 Sample Transfer Transfer the sample from the cylin-der into the measuring cell at room temperature but at least 5Cabove the pour point (as determined by Test Method D 5853)of the sample. Apply a back-pressure that is higher than
48、thevapor pressure of the sample at the introduction temperatureplus a minimum of 100 kPa (15 psi) for the piston movement.The applied back-pressure shall not exceed the maximum limitof the pressure transducer used in the vapor pressure apparatus.9. Preparation of Apparatus9.1 Prepare the instrument
49、for operation in accordance withthe manufacturers instructions.9.2 Rinse the measuring chamber, if necessary, with asolvent. Toluene has a low vapor pressure and can be usedsuccessfully. Rinsing is performed by drawing the solvent intothe chamber by the piston and expelling the solvent into thewaste container.9.3 To avoid contamination of the test specimen with theprevious sample or the solvent, rinse the measuring chamber aminimum of three times wit the sample to be tested. Fill themeasuring chamber with sample to at least half the totalvolume of the
