1、Designation: D5191 10bStandard Test Method forVapor Pressure of Petroleum Products (Mini Method)1This standard is issued under the fixed designation D5191; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.
2、A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This test method covers the use of automated vaporp
3、ressure instruments to determine the total vapor pressureexerted in vacuum by air-containing, volatile, liquid petroleumproducts, including automotive spark-ignition fuels with orwithout oxygenates (see Note 1). This test method is suitablefor testing samples with boiling points above 0C (32F) thate
4、xert a vapor pressure between 7 and 130 kPa (1.0 and 18.6psi) at 37.8C (100F) at a vapor-to-liquid ratio of 4:1.Measurements are made on liquid sample sizes in the rangefrom 1 to 10 mL. No account is made for dissolved water in thesample.NOTE 1An interlaboratory study was conducted in 2008 involving
5、 11different laboratories submitting 15 data sets and 15 different samples ofethanol-fuel blends containing 25 volume %, 50 volume %, and 75volume % ethanol. The results indicated that the repeatability limits ofthese samples are with in the published repeatability of this test method.on this basis,
6、 it can be concluded that D5191 is applicable to ethanol-fuelblends such as Ed75 and Ed85 (Specification D5798) and other ethanol-fuel blends with greater than 10 v% ethanol. See ASTM RR: D021694filed with ASTM for supporting data.2NOTE 2Samples can also be tested at other vapor-to-liquid ratios,tem
7、peratures, and pressures, but the precision and bias statements need notapply.NOTE 3The interlaboratory studies conducted in 1988, 1991, and2003 to determine the precision statements in Test Method D5191 did notinclude any crude oil in the sample sets. Test Method D6377, as well asIP 481, have been
8、shown to be suitable for vapor pressure measurementsof crude oils.1.1.1 Some gasoline-oxygenate blends may show a hazewhen cooled to 0 to 1C. If a haze is observed in 8.5, it shallbe indicated in the reporting of results. The precision and biasstatements for hazy samples have not been determined (se
9、eNote 15).1.2 This test method is suitable for calculation of the dryvapor pressure equivalent (DVPE) of gasoline and gasoline-oxygenate blends by means of a correlation equation (see Eq 1in 14.2). The calculated DVPE very closely approximates thedry vapor pressure that would be obtained on the same
10、 materialwhen tested by Test Method D4953.1.3 The values stated in SI units are regarded as standard.The inch-pound units given in parentheses are provided forinformation only.1.4 WARNINGMercury has been designated by manyregulatory agencies as a hazardous material that can causecentral nervous syst
11、em, kidney and liver damage. Mercury, orits vapor, may be hazardous to health and corrosive tomaterials. Caution should be taken when handling mercury andmercury containing products. See the applicable product Ma-terial Safety Data Sheet (MSDS) for details and EPAs website http:/www.epa.gov/mercury/
12、faq.htm - for additional infor-mation. Users should be aware that selling mercury and/ormercury containing products into your state or country may beprohibited by law.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of
13、the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. For specific safetywarning statements, see 7.2 through 7.8.2. Referenced Documents2.1 ASTM Standards:3D2892 Test Method for Distillation of Crude P
14、etroleum(15-Theoretical Plate Column)D4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4953 Test Method for Vapor Pressure of Gasoline andGasoline-Oxygenate Blends (Dry Method)D5798 Specification for Fuel Ethanol (Ed70-Ed85) forAutomotive Spark-Ignition EnginesD6299 Practice for
15、Applying Statistical Quality Assuranceand Control Charting Techniques to Evaluate AnalyticalMeasurement System Performance1This 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
16、 edition approved Oct. 1, 2010. Published November 2010. Originallyapproved in 1991. Last previous edition approved in 2010 as D519110a. DOI:10.1520/D5191-10B.2Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D02-1694.3For referen
17、ced 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 end of this standard.Copyri
18、ght ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.D6377 Test Method for Determination of Vapor Pressure ofCrude Oil: VPCRx(Expansion Method)D6378 Test Method for Determination of Vapor Pressure(VPX) of Petroleum Products, Hydrocarbons, andHyd
19、rocarbon-Oxygenate Mixtures (Triple ExpansionMethod)2.2 IP Standard:IP 481 Test Method for Determination of the Air SaturatedVapour Pressure (ASVP) of Crude Oil43. Terminology3.1 Definitions:3.1.1 fuel ethanol (Ed75Ed85)blend of ethanol and hy-drocarbon, of which the ethanol portion is nominally 75
20、to 85volume % denatured fuel ethanol.3.2 Definitions of Terms Specific to This Standard:3.2.1 absolute vapor pressurethe pressure of the air-freesample. It is calculated from the total vapor pressure of thesample by subtracting out the partial pressure of the dissolvedair.3.2.2 dry vapor pressure eq
21、uivalent (DVPE)a value cal-culated by a correlation equation (see 14.2) from the totalvapor pressure.3.2.2.1 DiscussionThe DVPE is expected to be equivalentto the value obtained on the sample by Test Method D4953,Procedure A.3.2.3 total vapor pressure (Ptot)the observed pressuremeasured in the exper
22、iment that is the sum of the partialpressure of the sample and the partial pressure of the dissolvedair.3.3 Abbreviations:3.3.1 DVPEdry vapor pressure equivalent3.3.2 Ptottotal vapor pressure4. Summary of Test Method4.1 A known volume of chilled, air-saturated sample isintroduced into a thermostatic
23、ally controlled, evacuated testchamber, or a test chamber with a moveable piston thatexpands the volume after sample introduction, the internalvolume of which is five times that of the total test specimenintroduced into the chamber. After introduction into the testchamber, the test specimen is allow
24、ed to reach thermal equi-librium at the test temperature, 37.8C (100F). The resultingrise in pressure in the chamber is measured using a pressuretransducer sensor and indicator. Only total pressure measure-ments (sum of the partial pressure of the sample and the partialpressure of the dissolved air)
25、 are used in this test method,although some instruments can measure the absolute pressureof the sample as well.4.2 The measured total vapor pressure is converted to a dryvapor pressure equivalent (DVPE) by use of a correlationequation (see Eq 1 in 14.2).5. Significance and Use5.1 Vapor pressure is a
26、 very important physical property ofvolatile liquids.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 suitablevolatility performa
27、nce.5.4 This test method is more precise than Test MethodD4953, uses a small sample size (1 to 10 mL), and requiresabout 7 min to complete the test.6. Apparatus6.1 Vapor Pressure ApparatusThe type of apparatus suit-able for use in this test method employs a small volume testchamber incorporating a t
28、ransducer for pressure measurementsand associated equipment for thermostatically controlling thechamber temperature and for evacuating the test chamber priorto sample introduction or expanding the volume after sampleintroduction by a moveable piston.6.1.1 The test chamber shall be designed to contai
29、n between5 and 50 mL of liquid and vapor and be capable of maintaininga vapor-to-liquid ratio between 3.95 to 1.00 and 4.05 to 1.00.NOTE 4The test chamber employed by the instruments used ingenerating the precision and bias statements were constructed of stainlesssteel, aluminum, or brass.NOTE 5Test
30、 chambers exceeding a 15 mL capacity can be used, butthe precision and bias statements (see Section 16) are not known to apply.6.1.2 The pressure transducer shall have a minimum opera-tional range from 0 to 177 kPa (0 to 25.7 psi) with a minimumresolution of 0.1 kPa (0.01 psi) and a minimum accuracy
31、 of60.8 kPa (60.12 psi). The pressure measurement system shallinclude associated electronics and readout devices to displaythe resulting pressure reading.6.1.3 A thermostatically controlled heater shall be used tomaintain the test chamber at 37.8 6 0.1C (100 6 0.2F) forthe duration of the vapor pres
32、sure measurement.6.1.4 A platinum resistance thermometer shall be used formeasuring the temperature of the test chamber with a resolu-tion of 0.1C (0.2F) and an accuracy of 0.1C (0.2F).6.1.5 The vapor pressure apparatus shall have provisions forintroduction of the test specimen into an evacuated tes
33、tchamber, or into a test chamber by a moveable piston, and forthe cleaning or purging of the chamber following or precedingthe test.6.2 Vacuum Pump, capable of reducing the pressure in thetest chamber to less than 0.01 kPa (0.001 psi) absolute.6.3 Syringe, (optional, depending on sample introduction
34、mechanism employed with each instrument) gas-tight, 1 to 20mL capacity with a 61 % or better accuracy and a 61%orbetter precision. If a syringe is used to measure the samplevolume, the capacity of the syringe should not exceed twotimes the volume of the test specimen being dispensed.6.4 Iced Water B
35、ath, Refrigerator, or Air Bath, for chillingthe samples and syringe to temperatures between 0 to 1C (32to 34F).6.5 Pressure Measuring Device, capable of measuring localstation pressure with an accuracy of 0.20 kPa (0.03 psi), orbetter, at the same elevation relative to sea level as theapparatus in t
36、he laboratory.4Available from the Energy Institute, 61 New Cavendish St., London, WIG 7AR,U.K.D5191 10b26.5.1 When a mercury barometer is not used as the pressuremeasuring device, the calibration of the pressure measuringdevice employed shall be periodically checked (with traceabil-ity to a national
37、ly recognized standard) to ensure that thedevice remains within the required accuracy specified in 6.5.6.6 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 me
38、asuring device shall be regularly verifiedin accordance with the annex section on Vacuum Sensors(A6.3) of Test Method D2892.7. Reagents and Materials7.1 Purity of ReagentsUse chemicals of at least 99 %purity for verification of instrument performance (see Section11). Unless otherwise indicated, it i
39、s intended that all reagentsconform to the specifications of the Committee on AnalyticalReagents of the American Chemical Society where suchspecifications are available.5Lower purities can be used,provided it is first ascertained that the reagent is of sufficientpurity to permit its use without less
40、ening the accuracy of thedetermination.7.1.1 The chemicals in sections 7.3, 7.4, 7.7, and 7.8(blended by mass with pentane) are suggested for verificationof instrument performance (see Section 11), based on thereference fuels analyzed in the 2003 interlaboratory study(ILS)6(see Table 1). Such refere
41、nce fuels are not to be used forinstrument calibration. Table 1 identifies the accepted referencevalue (ARV) and uncertainty limits, as well as the acceptabletesting range for each of the reference fuels listed.NOTE 6Verification fluids reported by 28 of the 29 D5191 data setparticipants in the 2003
42、 ILS6included the following (with number of datasets identified in parenthesis): 2,2-dimethylbutane (18), cyclopentane (5),pentane (2), 2,3-dimethylbutane (1), 3-methylpentane (1), and methanol(1).7.2 Cyclopentane,(WarningCyclopentane is flammableand a health hazard).7.3 2,2-Dimethylbutane,(Warning2
43、,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 flammable and ahealth hazard).7.6 2-Methylpentane,(Warning2-methylpentane is flam-mable and a health hazard).7.7 Pentane,(WarningPent
44、ane is flammable and a healthhazard).7.8 Toluene,(WarningToluene is flammable and a healthhazard).8. Sampling8.1 General Requirements:8.1.1 The extreme sensitivity of vapor pressure measure-ments to losses through evaporation and the resulting changesin composition is such as to require the utmost p
45、recaution andthe most meticulous care in the drawing and handling ofsamples.8.1.2 Obtain a sample and test specimen in accordance withPractice D4057, except do not use the “Sampling by WaterDisplacement” section for fuels containing oxygenates. Useeither a 250-mL or 1-L (1-qt) sized container filled
46、 between 70and 80 % with sample. For best testing precision (reproduc-ibility), it is recommended that a 1-L sized container be used.NOTE 7The current precision statements were derived from the 2003ILS6using samples in 250-mL and 1-L (1-qt) clear glass containers.However, samples in containers of ot
47、her sizes, as prescribed in PracticeD4057, may be used with the same ullage requirement if it is recognizedthat the precision can be affected. The differences in precision resultsobtained from 250-mL and 1-L containers were found to be statisticallysignificant, whereas there was no statistically obs
48、ervable bias detectedbetween 250-mL and 1-L containers. See Tables 2 and 3, as well as Figs.1 and 2 for more specific details on precision differences as a function ofDVPE value and container size. In general, numerically better repeatabil-ity values were determined at DVPE values 100 kPa, such as p
49、entane, theprecision appears to worsen with diminishing liquid volume in the bottle.It is recommended that if pentane is used, that the % capacity in thecontainer be $50 %.11.2 Values obtained within the acceptable testing rangeintervals in Table 1 indicate that the instrument is performingat the level deemed acceptable by this standard. If valuesoutside the acceptable testing range intervals are obtained,verify the quality of the pure compound(s) and re-check thecalibration of the instrument (see Section 10).12. Quality Control Checks12.1
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