1、Designation: D6378 18D6378 18aStandard 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 indi
2、cates the 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 automa
3、ted vapor pressure instruments to determine the vapor pressure exerted in vacuumby volatile, liquid petroleum products, hydrocarbons, and hydrocarbon-oxygenate mixtures including ethanol blends up to 85 %(volume fraction).This test method is suitable for testing samples with boiling points above 0 C
4、 (32 F) that exert a vapor pressurebetween 7 kPa and 150 kPa (1.0 psi and 21 psi) at 37.8 C (100 F) at a vapor-to-liquid ratio of 4:1. The liquid sample volume sizerequired for analysis is dependent upon the vapor-to-liquid ratio chosen (see Note 1) and the measuring chamber volume capacityof the in
5、strument (see 6.1.1 and Note 5).NOTE 1The test method is suitable for the determination of the vapor pressure of volatile, liquid petroleum products at temperatures from 0 C to100 C at vapor to liquid ratios of 4:1 to 1:1 (X = 4 to 1) and pressures up to 500 kPa (70 psi), but the precision statement
6、 (see Section 16) may not beapplicable.NOTE 2The precision (see Section 16) using 1 L containers was determined in a 2003 interlaboratory study (ILS);2 the precision using 250 mLcontainers was determined in a 2016 ILS.31.2 This test method also covers the use of automated vapor pressure instruments
7、to determine the vapor pressure exerted invacuum by aviation turbine fuels. This test method is suitable for testing aviation turbine fuel samples with boiling points above0 C (32 F) that exert a vapor pressure between 0 kPa and 110 kPa (0 psi and 15.5 psi) at a vapor-to-liquid ratio of 4:1, in thet
8、emperature range from 25 C to 100 C (77 F to 212 F).NOTE 3The precision (see Section 16) for aviation turbine fuels using 100 mL containers was determined in a 2007 ILS.41.3 The vapor pressure (VPX) determined by this test method at a vapor-liquid ratio of 4:1 (X = 4) of gasoline andgasoline-oxygena
9、te blends at 37.8 C can be correlated to the dry vapor pressure equivalent (DVPE) value determined by TestMethod D5191 (see 16.3). This condition does not apply when the sample is aviation turbine fuel.1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses
10、after SI units are provided forinformation only and are not considered standard.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety, health, and environmental p
11、ractices and determine the applicability ofregulatory limitations prior to use. For specific warning statements, see 7.2 7.8.1.6 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Deve
12、lopment of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.1 This test method is under the jurisdiction ofASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of S
13、ubcommitteeD02.08 on Volatility.Current edition approved June 1, 2018Dec. 1, 2018. Published September 2018January 2019. Originally approved in 1999. Last previous edition approved in 20162018as D6378 10 (2016).D6378 18. DOI: 10.1520/D6378-18.10.1520/D6378-18A.2 Supporting data have been filed at AS
14、TM International Headquarters and may be obtained by requesting Research Report RR:D02-1619. Contact ASTM CustomerService at serviceastm.org.3 Research 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:ILSe
15、nergyinst.org.4 Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:D02-1651. Contact ASTM CustomerService at serviceastm.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indi
16、cation of what changes have been made to the previous version. Becauseit may not be technically 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 c
17、onsidered the official document.*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 States12. Referenced Documents2.1 ASTM Standards:5D323 Test Method for Vapor Pressure of Petrole
18、um Products (Reid Method)D2892 Test Method for Distillation of Crude Petroleum (15-Theoretical Plate Column)D4057 Practice for Manual Sampling of Petroleum and Petroleum ProductsD4177 Practice for Automatic Sampling of Petroleum and Petroleum ProductsD4953 Test Method for Vapor Pressure of Gasoline
19、and Gasoline-Oxygenate Blends (Dry Method)D5191 Test Method for Vapor Pressure of Petroleum Products (Mini Method)D5842 Practice for Sampling and Handling of Fuels for Volatility MeasurementD5854 Practice for Mixing and Handling of Liquid Samples of Petroleum and Petroleum ProductsD6299 Practice for
20、 Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measure-ment System PerformanceD6300 Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and LubricantsD6708 Practice for Statistical Assessment and Improve
21、ment of Expected Agreement Between Two Test Methods that Purportto 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 calculated by a correlation equation from the total pressure (Test MethodD5191)
22、, which is equivalent to the value obtained on the sample by Test Method D4953, Procedure A.3.1.2 partial pressure from dissolved air (PPA), nthe pressure exerted in vacuum from dissolved air that escapes from theliquid phase into the vapor phase.3.1.3 Reid vapor pressure equivalent (RVPE)a value ca
23、lculated by a correlation equation from the TPX, which is equivalentto the value obtained on the sample by Test Method D323.3.1.4 total pressure (TPX),nthe pressure exerted in vacuum by air- and gas-containing petroleum products, components andfeedstocks, and other liquids, in the absence of undisso
24、lved water at a vapor-liquid ratio of X:1.3.1.5 vapor pressure (VPX),nthe total pressure minus the PPA in the liquid at a vapor-liquid ratio of X:1.VPX5TPX2PPA (1)4. Summary of Test Method4.1 Employing a measuring chamber with a built-in piston, a sample of known volume is drawn into the temperature
25、 controlledchamber at 20 C or higher. After sealing the chamber, the temperature of the chamber is increased to a specified valuesimultaneously with the first expansion. Two further expansions are performed to a final volume of (X + 1) times that of the testspecimen. After each expansion, the TPX is
26、 determined. The PPA and the solubility of air in the specimen are calculated from thethree resulting pressures. The (VPX) is calculated by subtracting the PPA in the liquid from TPX.NOTE 4For liquids containing very low levels of high vapor pressure contaminants, which behave like a gas, this test
27、method of determination ofthe PPA and gases may lead to wrong results since the partial pressure of the contaminants will be included in the PPA. This effect is shown when thevalue of the PPA and gases exceeds the average maximum limit of 7 kPa (1 psi).5. Significance and Use5.1 Vapor pressure is a
28、very important physical property of volatile liquids for shipping and storage.5.2 The vapor pressure of gasoline and gasoline-oxygenate blends is regulated by various government agencies.5.3 Specifications for volatile petroleum products generally include vapor pressure limits to ensure products of
29、suitablevolatility performance.5.4 In this test method, an air saturation procedure prior to the measurement is not required, thus eliminating losses of highvolatile compounds during this step. This test method is faster and minimizes potential errors from improper air saturation. Thistest method pe
30、rmits VPX determinations in the field.5.5 This test method can be applied in online applications in which an air saturation procedure prior to the measurement cannotbe performed.6. Apparatus6.1 The apparatus suitable for this test method employs a small volume, cylindrically shaped measuring chamber
31、 withassociated equipment to control the chamber temperature within the range from 0 C to 100 C. The measuring chamber shall5 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, re
32、fer to the standards Document Summary page on the ASTM website.D6378 18a2contain a movable piston with a maximum dead volume of less than 1 % of the total volume at the lowest position to allow sampleintroduction into the measuring chamber and expansion to the desired vapor-liquid ratio. A static pr
33、essure transducer shall beincorporated in the piston. The measuring chamber shall contain an inlet/outlet valve combination for sample introduction andexpulsion. The piston and the valve combination shall be at the same temperature as the measuring chamber to avoid anycondensation or excessive evapo
34、ration.6.1.1 The measuring chamber shall be designed to contain between 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 of the adjusted vapor-liquid ratio shall be within 0.05.NOTE 5The measuring chamber employed by the instruments use
35、d in generating the precision and bias statements were constructed of nickel platedaluminum and stainless steel with a total volume of 5 mL. Measuring chambers exceeding a 5 mL capacity can be used, but the precision and biasstatements (see Section 16) are not known to apply.6.1.2 The pressure trans
36、ducer shall have a minimum operational range from 0 kPa to 200 kPa (0 psi to 29 psi) with a minimumresolution of 0.1 kPa (0.01 psi) and a minimum accuracy of 60.2 kPa (60.03 psi). The pressure measurement system shall includeassociated electronics and readout devices to display the resulting pressur
37、e reading.6.1.3 Electronic temperature control shall be used to maintain the measuring chamber at the prescribed temperature within60.1 C for the duration of the vapor pressure measurement.6.1.4 Aplatinum resistance thermometer shall be used for measuring the temperature of the measuring chamber. Th
38、e minimumtemperature range of the measuring device shall be from 0 C to 100 C with a resolution of 0.1 C and an accuracy of 60.1 C.6.1.5 The vapor pressure apparatus shall have provisions for rinsing the measuring chamber with a solvent of low vapor pressureor with the next sample to be tested.6.2 V
39、acuum Pump for Calibration, capable of reducing the pressure in the measuring chamber to less than 0.01 kPa (0.001 psi)absolute.6.3 McLeod Vacuum Gauge or Calibrated Electronic Vacuum Measuring Device for Calibration, to cover at least the range from0.01 kPa to 0.67 kPa (0.1 mm to 5 mm Hg). The cali
40、bration of the electronic vacuum measuring device shall be regularly verifiedin accordance with Annex A6.3 on Vacuum Sensors in Test Method D2892.6.4 Pressure Measuring Device for Calibration, capable of measuring local station pressure with an accuracy and a resolutionof 0.1 kPa (1 mm Hg), or bette
41、r, at the same elevation relative to sea level as the apparatus in the laboratory.NOTE 6This test method does not give full details of instruments suitable for carrying out this test. Details on the installation, operation, andmaintenance of each instrument may be found in the manufacturers manual.7
42、. Reagents and Materials7.1 Purity of ReagentsUse chemicals of at least 99 % purity for verification of instrument performance (see Section 11).Unless otherwise indicated, it is intended that all reagents conform to the specifications of the Committee of Analytical Reagentsof the American Chemical S
43、ociety6 where such specifications are available. Lower purities can be used, provided it is firstascertained that the reagent is of sufficient purity to permit its use without lessening the accuracy of the determination.7.1.1 The chemicals in 7.3, 7.4, and 7.7 are suggested for verification of instr
44、ument performance (see Section 11), based on thereference fuels analyzed in the 2003 interlaboratory study (ILS) (see 16.1, Table 1, and Note 17). Such reference fuels are not tobe used for instrument calibration. Table 1 identifies the accepted reference value (ARV) and uncertainty limits, as well
45、as theacceptable testing range for each of the reference fuels listed.NOTE 7Verification fluids reported by 12 of the D6378 data set participants in the 2003 ILS (see 16.1) included the following (with number of datasets identified in parentheses): 2,2-dimethylbutane (11), and 2,3-dimethylbutane (1)
46、.6 Reagent Chemicals, American Chemical Society Specifications, American Chemical 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 Pharma
47、copeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.TABLE 1 Accepted Reference Value (ARV) and Acceptable Testing Range for Reference Fluids (Note 17)Reference Fluid ARV VP4 (37.8 C) Uncertainty,(kPa)Recommended InstrumentManufacturer Tolerance,(kPa)Acceptable Tes
48、ting Range forReference Fuel VP4 (37.8 C),(kPa)Pentane 107.9 0.2 1.0 107.9 1.2 (106.7 to 109.1)2,2 Dimethylbutane 68.8 0.2 1.0 68.8 1.2 (67.6 to 70.0)2,3 Dimethylbutane 51.7 0.2 1.0 51.7 1.2 (50.5 to 52.9)Reference Fluid ARV VP4 (37.8 C) Uncertainty,(psi)Recommended InstrumentManufacturer Tolerance,
49、(psi)Acceptable Testing Range forReference Fuel VP4 (37.8 C),(psi)Pentane 15.65 0.03 0.14 15.65 0.17 (15.48 to 15.82)2,2 Dimethylbutane 9.98 0.03 0.14 9.98 0.17 (9.81 to 10.15)2,3 Dimethylbutane 7.50 0.03 0.14 7.50 0.17 (7.33 to 7.67)D6378 18a37.2 Cyclopentane, (WarningCyclopentane is flammable and a health hazard).7.3 2,2-Dimethylbutane, (Warning2,2-dimethylbutane is flammable and a health hazard).7.4 2,3-Dimethylbutane, (Warning2,3-dimethylbutane is flammable and a health hazard).7.5 Met
