1、Designation: D6378 18Standard Test Method forDetermination of Vapor Pressure (VPX) of PetroleumProducts, Hydrocarbons, and Hydrocarbon-OxygenateMixtures (Triple Expansion Method)1This standard is issued under the fixed designation D6378; the number immediately following the designation indicates the
2、 year oforiginal adoption or, in the 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 vapor
3、pressure instruments to determine the vapor pressure exerted invacuum by volatile, liquid petroleum products, hydrocarbons,and hydrocarbon-oxygenate mixtures including ethanol blendsup to 85 % (volume fraction). This test method is suitable fortesting samples with boiling points above 0 C (32 F) tha
4、texert a vapor pressure between 7 kPa and 150 kPa (1.0 psi and21 psi) at 37.8 C (100 F) at a vapor-to-liquid ratio of 4:1. Theliquid sample volume size required for analysis is dependentupon the vapor-to-liquid ratio chosen (see Note 1) and themeasuring chamber volume capacity of the instrument (see
5、6.1.1 and Note 5).NOTE 1The test method is suitable for the determination of the vaporpressure of volatile, liquid petroleum products at temperatures from 0 Cto 100 C at vapor to liquid ratios of 4:1 to 1:1 (X=4to1)andpressuresup to 500 kPa (70 psi), but the precision statement (see Section 16) mayn
6、ot be applicable.NOTE 2The precision (see Section 16) using 1 L containers wasdetermined in a 2003 interlaboratory study (ILS);2the precision using250 mL containers was determined in a 2016 ILS.31.2 This test method also covers the use of automated vaporpressure instruments to determine the vapor pr
7、essure exerted invacuum by aviation turbine fuels. This test method is suitablefor testing aviation turbine fuel samples with boiling pointsabove 0 C (32 F) that exert a vapor pressure between 0 kPaand 110 kPa (0 psi and 15.5 psi) at a vapor-to-liquid ratio of4:1, in the temperature range from 25 C
8、to 100 C (77 F to212 F).NOTE 3The precision (see Section 16) for aviation turbine fuels using100 mL containers was determined in a 2007 ILS.41.3 The vapor pressure (VPX) determined by this testmethod at a vapor-liquid ratio of 4:1 (X = 4) of gasoline andgasoline-oxygenate blends at 37.8 C can be cor
9、related to thedry vapor pressure equivalent (DVPE) value determined byTest Method D5191 (see 16.3). This condition does not applywhen the sample is aviation turbine fuel.1.4 The values stated in SI units are to be regarded asstandard. The values given in parentheses after SI units areprovided for in
10、formation only and are not considered standard.1.5 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, health, and environmental practices and deter-mine the appli
11、cability of regulatory limitations prior to use.For specific warning statements, see 7.2 7.8.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Stand
12、ards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:5D323 Test Method for Vapor Pressure of Petroleum Products(Reid Method)D2892 Test Method for Distillation of Crude Petroleum(15-Theoretical Pl
13、ate Column)D4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of Petroleum andPetroleum Products1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibilit
14、y ofSubcommittee D02.08 on Volatility.Current edition approved June 1, 2018. Published September 2018. Originallyapproved in 1999. Last previous edition approved in 2016 as D6378 10 (2016).DOI: 10.1520/D6378-18.2Supporting data have been filed at ASTM International Headquarters and maybe obtained by
15、 requesting Research Report RR:D02-1619. ContactASTM CustomerService at serviceastm.org.3Research Report IP 394 (EN 130161) and IP 619 (EN 130163) 2016,available from the Energy Institute, 61 New Cavendish Street, London W1G 7AR,UK , email: ILSenergyinst.org.4Supporting data have been filed at ASTM
16、International Headquarters and maybe obtained by requesting Research Report RR:D02-1651. ContactASTM CustomerService at serviceastm.org.5For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume in
17、formation, refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in ac
18、cordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1D4953 Test Method for Vapor P
19、ressure of Gasoline andGasoline-Oxygenate Blends (Dry Method)D5191 Test Method for Vapor Pressure of Petroleum Prod-ucts (Mini Method)D5842 Practice for Sampling and Handling of Fuels forVolatility MeasurementD5854 Practice for Mixing and Handling of Liquid Samplesof Petroleum and Petroleum Products
20、D6299 Practice for Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System PerformanceD6300 Practice for Determination of Precision and BiasData for Use in Test Methods for Petroleum Products andLubricantsD6708 Practice for Statistical Assessmen
21、t and Improvementof Expected Agreement Between Two Test Methods thatPurport to Measure the Same Property of a Material3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 dry vapor pressure equivalent (DVPE)a value cal-culated by a correlation equation from the total pressure (Test
22、Method D5191), which is equivalent to the value obtained onthe sample by Test Method D4953, Procedure A.3.1.2 partial pressure from dissolved air (PPA), nthepressure exerted in vacuum from dissolved air that escapesfrom the liquid phase into the vapor phase.3.1.3 Reid vapor pressure equivalent (RVPE
23、)a value cal-culated by a correlation equation from the TPX, which isequivalent to the value obtained on the sample by Test MethodD323.3.1.4 total pressure (TPX), nthe pressure exerted invacuum by air- and gas-containing petroleum products, com-ponents and feedstocks, and other liquids, in the absen
24、ce ofundissolved water at a vapor-liquid ratio of X:1.3.1.5 vapor pressure (VPX), nthe total pressure minus thePPA in the liquid at a vapor-liquid ratio of X:1.VPX5 TPX2 PPA (1)4. Summary of Test Method4.1 Employing a measuring chamber with a built-in piston,a sample of known volume is drawn into th
25、e temperaturecontrolled chamber at 20 C or higher. After sealing thechamber, the temperature of the chamber is increased to aspecified value simultaneously with the first expansion. Twofurther expansions are performed to a final volume of (X + 1)times that of the test specimen. After each expansion,
26、 the TPXis determined. The PPAand the solubility of air in the specimenare calculated from the three resulting pressures. The (VPX)iscalculated by subtracting the PPA in the liquid from TPX.NOTE 4For liquids containing very low levels of high vapor pressurecontaminants, which behave like a gas, this
27、 test method of determinationof the PPA and gases may lead to wrong results since the partial pressureof the contaminants will be included in the PPA. This effect is shown whenthe value of the PPA and gases exceeds the average maximum limit of7 kPa (1 psi).5. Significance and Use5.1 Vapor pressure i
28、s a very important physical property ofvolatile liquids for shipping and storage.5.2 The vapor pressure of gasoline and gasoline-oxygenateblends is regulated by various government agencies.5.3 Specifications for volatile petroleum products generallyinclude vapor pressure limits to ensure products of
29、 suitablevolatility performance.5.4 In this test method, an air saturation procedure prior tothe measurement is not required, thus eliminating losses ofhigh volatile compounds during this step. This test method isfaster and minimizes potential errors from improper air satu-ration. This test method p
30、ermits VPXdeterminations in thefield.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, cylindrically shaped measuring chamber wi
31、thassociated equipment to control the chamber temperaturewithin the range from 0 C to 100 C. The measuring chambershall contain a movable piston with a maximum dead volumeof less than 1 % of the total volume at the lowest position toallow sample introduction into the measuring chamber andexpansion t
32、o the desired vapor-liquid ratio. A static pressuretransducer shall be incorporated in the piston. The measuringchamber shall contain an inlet/outlet valve combination forsample introduction and expulsion. The piston and the valvecombination shall be at the same temperature as the measuringchamber t
33、o avoid any condensation or excessive evaporation.6.1.1 The measuring chamber shall be designed to containbetween 5 mL and 15 mL of liquid and vapor and be capable ofmaintaining a vapor-liquid ratio of 4:1 to 1:1. The accuracy ofthe adjusted vapor-liquid ratio shall be within 0.05.NOTE 5The measurin
34、g chamber employed by the instruments used ingenerating the precision and bias statements were constructed of nickelplated aluminum and stainless steel with a total volume of 5 mL.Measuring chambers exceeding a 5 mL capacity can be used, but theprecision and bias statements (see Section 16) are not
35、known to apply.6.1.2 The pressure transducer shall have a minimum opera-tional range from 0 kPa to 200 kPa (0 psi to 29 psi) with aminimum resolution of 0.1 kPa (0.01 psi) and a minimumaccuracy of 60.2 kPa (60.03 psi). The pressure measurementsystem shall include associated electronics and readout d
36、evicesto display the resulting pressure reading.6.1.3 Electronic temperature control shall be used to main-tain the measuring chamber at the prescribed temperaturewithin 60.1 C for the duration of the vapor pressure measure-ment.6.1.4 A platinum resistance thermometer shall be used formeasuring the
37、temperature of the measuring chamber. Theminimum temperature range of the measuring device shall befrom 0 C to 100 C with a resolution of 0.1 C and anaccuracy of 60.1 C.D6378 1826.1.5 The vapor pressure apparatus shall have provisions forrinsing the measuring chamber with a solvent of low vaporpress
38、ure or with the next sample to be tested.6.2 Vacuum Pump for Calibration, capable of reducing thepressure in the measuring chamber to less than 0.01 kPa(0.001 psi) absolute.6.3 McLeod Vacuum Gauge or Calibrated ElectronicVacuum Measuring Device for Calibration, to cover at least therange from 0.01 k
39、Pa to 0.67 kPa (0.1 mm to 5 mm Hg). Thecalibration of the electronic vacuum measuring device shall beregularly verified in accordance with Annex A6.3 on VacuumSensors in Test Method D2892.6.4 Pressure Measuring Device for Calibration, capable ofmeasuring local station pressure with an accuracy and a
40、resolution of 0.1 kPa (1 mm Hg), or better, at the sameelevation relative to sea level as the apparatus in the laboratory.NOTE 6This test method does not give full details of instrumentssuitable for carrying out this test. Details on the installation, operation, andmaintenance of each instrument may
41、 be found in the manufacturersmanual.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 of Analytica
42、lReagents of the American Chemical Society6where suchspecifications are available. Lower purities can be used,provided it is first ascertained that the reagent is of sufficientpurity to permit its use without lessening the accuracy of thedetermination.7.1.1 The chemicals in 7.3, 7.4, and 7.7 are sug
43、gested forverification of instrument performance (see Section 11), basedon the reference fuels analyzed in the 2003 interlaboratorystudy (ILS) (see 16.1, Table 1, and Note 17). Such referencefuels are not to be used for instrument calibration. Table 1identifies the accepted reference value (ARV) and
44、 uncertaintylimits, as well as the acceptable testing range for each of thereference fuels listed.NOTE 7Verification fluids reported by 12 of the D6378 data setparticipants in the 2003 ILS (see 16.1) included the following (withnumber of data sets identified in parentheses): 2,2-dimethylbutane (11),
45、and 2,3-dimethylbutane (1).7.2 Cyclopentane, (WarningCyclopentane is flammableand a health hazard).7.3 2,2-Dimethylbutane, (Warning2,2-dimethylbutane isflammable and a health hazard).7.4 2,3-Dimethylbutane, (Warning2,3-dimethylbutane isflammable and a health hazard).7.5 Methanol, (WarningMethanol is
46、 flammable and ahealth hazard).7.6 2-Methylpentane, (Warning2-methylpentane is flam-mable and a health hazard).7.7 Pentane, (WarningPentane is flammable and a healthhazard).7.8 Toluene, (WarningToluene is flammable and a healthhazard).8. Sampling and Sample Introduction8.1 General Requirements:8.1.1
47、 The extreme sensitivity of vapor pressure measure-ments to losses through evaporation and the resulting changesin composition is such as to require the utmost precaution andthe most meticulous care in the drawing and handling ofsamples.8.1.2 Obtain a sample and test specimen in accordance withPract
48、ice D4057, D4177, D5842,orD5854 when appropriate,except do not use the Sampling by Water Displacement sectionfor fuels containing oxygenates.8.1.2.1 For gasolines and gasoline-oxygenate blends, useeither a 250 mL or 1 L (1 qt) sized container filled between70 % and 80 % with sample. Samples in conta
49、iners of othersizes, as prescribed in Practice D4057, may be used with thesame ullage requirements, but precision can be affected.NOTE 8Relative bias information when testing gasoline and gasoline-oxygenate blends using 250 mL or 1 L containers is given in Section 16.8.1.2.2 For aviation turbine fuel, use a 100 mL size con-tainer filled to a minimum of 80 % with sample. However,samples in containers of other sizes as prescribed in PracticeD4057 may be used, with the same ullage requirement, but theprecision can be affected.8.1.3 Perfor
