1、Designation: D 6377 08An 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 () 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 exerted invacuum of crude oils. This test method is suitable for testingsamples that exert a vapor pressure between 25 and 180 kPa at37.8C at vapor-liquid ratios from 4:1 to 0.02:1 (X=4to0.02).NOTE 1This test method is suitable for the determination of the vaporpressure of crude o
4、ils at temperatures from 0 to 100C and pressures upto 500 kPa, but the precision and bias statements (see Section 14) may notbe applicable.1.2 This test method allows the determination of vaporpressure for crude oil samples having pour points above 0C.1.3 The values stated in SI units are to be rega
5、rded asstandard. No 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 determi
6、ne the applica-bility of regulatory limitations prior to use. For specificwarning statements, see 7.2.1-7.3.2.2. Referenced 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 Plat
7、e Column)D 3700 Practice for Obtaining LPG Samples Using a Float-ing Piston CylinderD 4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD 4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD 5191 Test Method for Vapor Pressure of Petroleum Prod-ucts (Mini Method
8、)D 5853 Test Method for Pour Point of Crude OilsD 6708 Practice for Statistical Assessment and Improve-ment of Expected Agreement Between Two Test Methodsthat Purport to Measure the Same Property of a Material3. Terminology3.1 Definitions:3.1.1 platinum resistance thermometer, ntemperaturemeasuring
9、device constructed with a length 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 Standar
10、d:3.2.1 dead crude oila term usually employed for crudeoils that, when exposed to normal atmospheric pressure atroom temperature, will not result in actual boiling of thesample.3.2.1.1 DiscussionSampling and handling of dead crudeoils can usually be done without problems in normal, non-pressurized s
11、ample containers, such as cans and so forth.3.2.2 live crude oila 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.3.2.2.1 DiscussionSampling and handling of samples o
12、flive crude oils will necessitate the use of pressure cylinders andpreclude the use of normal sample containers, such as cans andso forth.3.2.3 Reid vapor pressure equivalent (RVPE)a value cal-culated by a defined correlation equation (see 14.3) fromVPCR4, that is expected to be comparable to the va
13、por pressurevalue obtained by Test Method D 323.3.2.4 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 combination thereof, where X may varyfrom 4 to 0.0
14、2.1This 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 July 1, 2008. Published August 2008. Originallyapproved in 1999. Last previous edition approved in 200
15、3 as D 637703.2For 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 Changes section appears at the e
16、nd of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.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 o
17、il at x vaporliquid ratio4. Summary of Test Method4.1 Employing a measuring chamber with a built-in piston,a sample of known volume is drawn from the sample containerinto the temperature controlled chamber at 20C or higher.After sealing the chamber, the volume is expanded by movingthe piston until t
18、he final volume produces the desired V/Lvalue. The temperature of the measuring chamber 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 pro
19、cedureby shaking the measuring chamber to achieve pressure equi-librium in a reasonable time of 5 to 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 a
20、nd Use5.1 Vapor pressure of crude oil at various V/Ls is animportant physical property 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 han
21、dling and initial refinerytreatment.5.3 The vapor pressure determined by this test method at avapor-liquid ratio of 4:1 (VPCR4) of crude oil at 37.8C can berelated to the vapor pressure value determined on the samematerial when tested by Test Method D 323 (see AppendixX1).5.4 Chilling and air satura
22、tion of the sample prior to thevapor pressure measurement is not required.5.5 This test method can be applied in online applications inwhich an air saturation procedure prior to the measurementcannot be performed.6. Apparatus6.1 The apparatus suitable for this test method employs asmall volume, cyli
23、ndrically shaped measuring chamber withassociated equipment to control the chamber temperaturewithin the range from 0 to 100C. 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 th
24、e 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 the valve combination shallbe at the same temperature as t
25、he measuring chamber to avoidany condensation or excessive evaporation.6.1.1 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 V/L shallbe within 0.01.NOTE 3The measuring chambers employ
26、ed by the instruments usedin generating the precision and bias statements were 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)
27、may not beapplicable.6.1.2 The pressure transducer shall have a minimum opera-tional range from 0 to 500 kPa with a minimum resolution of0.1 kPa and a minimum accuracy of 60.5 kPa. The pressuremeasurement system shall include associated electronics andreadout devices to display the resulting pressur
28、e 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 thermometer shall be used formeasuring the temperature of the measuring chamber. Theminimum temperature r
29、ange of the measuring device shall befrom 0C to 100C with a resolution of 0.1C and an accuracyof 60.1C.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
30、 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 measuring chamber to less than 0.01 kPaabsolute.6.3 McLeod Vacuum Gage or Calibrated Electronic VacuumM
31、easuring Device for Calibration, to cover at least the rangeof 0.01 to 0.67 kPa. The calibration of the electronic measuringdevice shall be regularly verified in accordance with Annex Aof Test Method D 2892.6.4 Pressure Measuring Device for Calibration, capable ofmeasuring local station pressure wit
32、h an accuracy and aresolution of 0.1 kPa or better, at the same elevation relative tosea level as the apparatus in the laboratory.NOTE 4This standard does not give full details of instruments suitableTABLE 1 Accepted Reference Value (ARV) and Acceptable Testing Range for Air Saturated Reference Flui
33、dsAReference FluidARV Ptot 6 Uncertainty,(kPa)Recommended InstrumentManufacturer Tolerance,(kPa)Acceptable Testing Rangefor Reference Fuel Ptot,(kPa)Pentane 112.8 6 0.2 6 1.0 112.8 6 1.2 (111.6 to 114.0)2,2 Dimethylbutane 74.1 6 0.2 6 1.0 74.1 6 1.2 (72.9 to 75.3)2,3 Dimethylbutane 57.1 6 0.2 6 1.0
34、57.1 6 1.2 (55.9 to 58.3)ASupporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR: D021619.D6377082for carrying out this test. Details on the installation, operation andmaintenance of each instrument may be found in the manufacturersman
35、ual.7. Reagents and Materials7.1 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 AnalyticalReagents of the American Chemica
36、l Society where suchspecifications 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 i
37、nstrument performance (see Section 11),based on the air saturated reference fuels analyzed in the TestMethod D 5191 2003 interlaboratory study (ILS)4(see Table1). Ptotused in Test Method D 5191 is equivalent to VPCR4used in this test method). Such reference fuels are not to beused for instrument cal
38、ibration. Table 1 identifies the acceptedreference value (ARV) and uncertainty limits, as well as theacceptable testing 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 an
39、d the inlet and outlet 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
40、.3.1 Toluene,(WarningToluene 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 chang
41、esin 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 only be used for dead crude oil and if PracticeD 3700 i
42、s impractical.NOTE 5Sampling in accordance with Practice D 4177 may also beused instead of Practice D 4057.8.1.2 For sampling in accordance with Practice D 3700,afloating piston cylinder with a minimum sample volume of 200mL shall be used if the overall volume of the test specimenrequired for the va
43、por pressure determination, 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 plus 100kPa for the shifting of th
44、e piston. The maximum back-pressureshall not exceed the maximum measurement pressure of theapparatus pressure transducer. Compressed air, or any other,non-flammable compressed gas, can be used as the back-pressuring agent. The floating piston cylinder shall haveprovisions for mechanical stirring of
45、the sample and a secondvalve at the inlet for rinsing.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 in an appropriate room orrefrigerator.8.1.4 Perform the vapor pressure determination on the firstt
46、est 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 case of quality control checks with purecompounds (see 11.1), smaller sample containers withoutap
47、plied 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 under pressure. Rinse the cylinder byopening the rinsing valve until the crude oil emerges at these
48、cond 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 filling of the cylinder to be at least 200 mL.NOTE 6The current precision statements were derived from th
49、e 2005ILS using samples 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 PracticeD 4057. Use either a 250-mL or 1-L sized container filledbetween 70 and 80 % 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
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