1、Designation: D7975 14Standard Test Method forDetermination of Vapor Pressure of Crude Oil:VPCRx-F(TmC) (Manual Expansion Field Method)1This standard is issued under the fixed designation D7975; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、 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. Scope1.1 This test method covers the use of manual vaporpressure instruments to determine the vapor pres
3、sure of crudeoils exerted in a vacuum. This test method is suitable for testingsamples that exert a vapor pressure between 25 kPa and180 kPa at 37.8 C at vapor/liquid ratios from 4:1 to 0.25:1 (X= 4 to 0.25, see 3.2.4).NOTE 1This test method is suitable for the determination of the vaporpressure of
4、crude oils at temperatures from 0 C to 60 C and pressures upto 500 kPa, but the precision and bias statements (see Section 15) may notbe applicable.1.2 This test method is meant primarily for use under fieldconditions for immediate evaluation of vapor pressure forstorage, transport, or operational u
5、ses.1.3 This test method is not intended for use in custodytransfer applications. Test Method D6377 shall be used forcustody transfer applications.1.4 This test method provides a reasonable confirmation forthe presence of light ends in the source material given that thepartial pressure of low boilin
6、g components contribute signifi-cantly to total vapor pressure.1.5 This test method allows both sample collection andsubsequent vapor pressure measurement of crude oil samplesdirectly from the sample source. The collected sample mayalso be transferred to an automated vapor pressure instrumentsuch as
7、 used for Test Method D6377. The field test apparatusis suitable for transportation provided suitable over-pack isused to meet the regulations for the transportation of dangerousgoods in the transportation jurisdiction(s).1.6 This test method allows the determination of vaporpressure for crude oil s
8、amples having pour points below 0 Cand flow at the sampling conditions to allow inlet to theapparatus.1.7 The values stated in SI units are to be regarded asstandard.1.7.1 ExceptionOther units of measurement are includedin this standard for ease of use in multiple jurisdictions.1.8 This standard doe
9、s 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 Documents2.1 ASTM Stan
10、dards:2D323 Test Method for Vapor Pressure of Petroleum Products(Reid Method)D1193 Specification for Reagent WaterD5191 Test Method for Vapor Pressure of Petroleum Prod-ucts (Mini Method)D5853 Test Method for Pour Point of Crude OilsD6377 Test Method for Determination of Vapor Pressure ofCrude Oil:
11、VPCRx(Expansion Method)3. Terminology3.1 Definitions:3.1.1 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 Standard:3.2.1 dead crude oil, na term usually employed for crudeoi
12、ls that, when exposed to normal atmospheric pressure atroom temperature, will not result in actual boiling of thesample.3.2.1.1 DiscussionThese crudes will have vapor pressuresbelow atmospheric pressure at room temperature.3.2.1.2 DiscussionThis method will provide vapor pres-sure information that w
13、ill allow the user to determine if a crudeoil is considered “dead” or “live.” A crude oil shall always beconsidered “live” until the vapor pressure can be established.Sampling and handling of dead crude oils can usually be done1This test method is under the jurisdiction of ASTM Committee D02 onPetro
14、leum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.08 on Volatility.Current edition approved Dec. 1, 2014. Published February 2015. DOI: 10.1520/D7975-14.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service
15、 at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1without concern in normal, non-pressurized sampl
16、e containers,such as cans and other atmospheric containers.3.2.2 light ends, ncomponents that cannot be maintainedas a liquid at atmospheric pressure at temperatures greater than0 C.3.2.2.1 DiscussionThis includes any materials that haveatmospheric boiling points below 0 C including methane,ethane,
17、propane, butane, and fixed gases such as H2S, CO2,N2,O2,H2, CO.3.2.3 live crude oil, na term usually employed for crudeoils contained in pressurized systems that, when brought tonormal atmospheric pressure at room temperature, will resultin actual boiling of the sample.3.2.3.1 DiscussionSampling and
18、 handling of samples oflive crude oils will necessitate the use of the field test apparatusand preclude the use of normal sample containers, such as cansand other atmospheric containers.3.2.4 vapor pressure of crude oil field measurement(VPCRX-F), nthe pressure exerted in an evacuated chamberat a va
19、por-liquid ratio of X:1 by conditioned or unconditionedcrude oil, which may contain gas, air or water, or a combina-tion thereof, where X may vary from 4 to 0.25.3.2.4.1 DiscussionThis measurement is performed usingthe field test apparatus described herein.3.3 Abbreviations:3.3.1 ARV, naccepted refe
20、rence value.3.3.2 RVP, nReid Vapor Pressure.3.3.3 V/L, nvapor/liquid ratio.3.3.4 VPCRx-F(TmC), nvapor pressure of crude oil field(-F) measurement at X vapor/liquid ratio at (TmC) measuredtemperature.3.3.5 STP, nStandard Pressure (101.325 kPa) and Tem-perature (0 C)4. Summary of Test Method4.1 Using
21、a portable variable volume measurement chamberwith a built-in piston, a sample of crude oil of known volumeis drawn from the sample point or sample container into thefield test apparatus (see 7.1). After sealing the chamber, thevolume is expanded by moving the piston until the finalvolume produces t
22、he desired V/L value. The temperature of themeasuring chamber is then regulated to a specific measuringtemperature if required (see 7.2).4.2 After temperature and pressure equilibrium, the mea-sured pressure is recorded as the VPCRX-F(TmC) of thesample. The test specimen is mixed during the measurin
23、gprocedure by shaking the measuring chamber to achievepressure equilibrium in a reasonable time of 1 min to 5 min.4.3 For results related to Test Method D323, the finalvolume of the measuring chamber shall be five times the testspecimen volume (4:1 V/L ratio) and the measuring tempera-ture shall be
24、37.8 C. The 4:1 V/L ratio is based on filling themeasurement chamber 20 % full with liquid with vapor expan-sion to 100 %.4.4 For the purpose of transportation, a lower V/L ratio isdesirable to simulate the vapor pressure in vessel with 20 %outage. Filling the measurement chamber with 80 % liquid an
25、dexpanding to 100 % will provide a 0.25:1 V/L ratio.5. Significance and Use5.1 Vapor pressure of crude oil at various vapor/liquid ratiosis an important physical property for transport, storage, andrefinery operations.5.2 Vapor pressure of crude oil is important to crude oilproducers, regulators, tr
26、ansporters and refiners for generalhandling, transportation, and initial refinery treatment.5.3 The direct sample collection and subsequent, in place,vapor pressure measurement without the need for furthersample handling eliminates the potential loss of light hydro-carbon material from the sample. T
27、he combination of samplingand testing may produce higher results than Test Method D323.5.4 Chilling and air saturation of the sample prior to thevapor pressure measurement (as required in Test MethodD323) is not required in this test method.6. Interferences6.1 Exposure of a sample to the atmosphere
28、will result in airsaturation of the sample and loss of volatile material. At lowV/L ratios, the pressure exerted by air saturation can have amaterial effect on the vapor pressure measurement. Sampleexposure to the atmosphere is avoided by sampling directlyinto the field test apparatus (see 7.1) from
29、 the sample source.The sample source shall not be an atmospheric container, suchas a can or bottle, since vapor pressure measurement resultscan be impacted by air saturation and loss of volatile material.7. Apparatus7.1 Field Test Apparatus3The apparatus is shown in Fig.1 and described in detail in
30、Annex A1.7.1.1 The measuring chamber shall be designed to have atotal volume of 100 mL to 120 mL and shall be capable ofmaintaining a V/L of 4:1 to 0.25:1. The accuracy of theadjusted V/L shall be within 60.01.NOTE 2The measuring chambers employed by the instruments used ingenerating the precision a
31、nd bias statements were constructed as per A1.1,with a total volume of 100 mL to 120 mL. Measuring chambers exceedinga 120 mL capacity and different design can be used, but the precision andbias statement (see Section 15) may not be applicable.7.1.2 The vapor pressure apparatus shall have provisions
32、 tomeasure the sample vapor pressure (vapor pressure measure-ment gauge) and shall have a minimum operational range from0 kPa to 200 kPa with a minimum resolution of 5 kPa and aminimum accuracy of 62 kPa (see A1.1.1.3).NOTE 3Many gauges will provide a positive and negative scale withzero considered
33、barometric pressure (101.325 kPa at STP). For example:3The sole source of supply of the apparatus known to the committee at this timeis Parkes Scientific Inc. 17360-108 Ave NW, Edmonton, AB, Canada T5S 1E8,(780) 484-1849. If you are aware of alternative suppliers, please provide thisinformation to A
34、STM International Headquarters. Your comments will receivecareful consideration at a meeting of the responsible technical committee,1whichyou may attend.D7975 142Gauge scales will read 100 kPa to 100 kPa but the overall operatingrange is 200 kPa.7.1.3 The vapor pressure apparatus shall have provisio
35、ns tomeasure the sample source pressure (source pressure measure-ment gauge) and shall have a minimum operational range from0 kPa to 400 kPa with a minimum resolution of 20 kPa and aminimum accuracy of 610 kPa.7.1.4 The vapor pressure apparatus shall have provisions forrinsing the measuring chamber
36、with the next sample to betested or with a solvent of low vapor pressure.7.1.5 The vapor pressure apparatus shall be of such configu-ration as to be easily shaken during the measurement procedurewith a minimum frequency of 1 cycle per second. Shaking isintended to be performed by hand or could be pe
37、rformed bymechanical shaker or equivalent.7.1.6 The vapor pressure apparatus shall be equipped with apressure relief device set to a maximum pressure of 700 kPa(nominal 100 psi).7.2 Temperature Controlled Bath (Optional)A water orother suitable liquid bath capable of maintaining the desiredtest temp
38、erature between 0 C and 60 C. Temperature con-trolled bath shall be suitable in length, width and depth tocompletely immerse the measurement chamber while it is in ahorizontal position. Other suitable heating devices may be usedprovided the test temperatures are within the manufacturersspecification
39、 for the measurement gauges. Examples of othersuitable heating devices may include: ovens, air baths, jacket orhot-block type heaters.7.3 Temperature Controlled Bath Temperature MeasuringDevice (Optional)An electronic measuring device such as aresistance device or thermocouple capable of measuring t
40、hetemperature of the temperature control bath with a resolution of0.5 C and an accuracy of 62 C.7.4 Vapor Pressure Apparatus Temperature Measuring De-vices (Acceptable Devices):7.4.1 Asurface temperature measuring device, such as an IRthermal gun or surface mounted liquid crystal thermometer,capable
41、 of measuring the temperature of the measurementcylinder with a resolution of 0.5 C and an accuracy of 62 C.7.4.2 An electronic measuring device such as a resistancedevice or thermocouple inserted into a thermal well within thepiston rod capable of measuring the temperature of themeasurement cylinde
42、r with a resolution of 0.5 C and anaccuracy of 62 C.7.5 Portable BarometerA barometer with minimum pres-sure range of 95 kPa and 105 kPa with an accuracy of 60.5 %of reading and a resolution of 0.05 kPa.7.6 Top Loading BalanceA top loading balance with acapacity of 500 g to 3 digits accuracy 60.001
43、g.7.7 Vacuum PumpA vacuum pump capable of generatinga minimum vacuum of 1.3 kPa.7.8 Low Pressure Tubing6.35 mm (14 in.) inert flexibletubing for transferring fluids at atmospheric pressure.7.9 Low Pressure Tubing3.175 mm (18 in.) inert flexibletubing for transferring fluids at atmospheric pressure.7
44、.10 High Pressure Tubing6.35 mm (14 in.) inert flexibletubing for transferring fluids up to 689 kPa (100 psi).7.11 Purge ContainerA container suitable for purgingfluids during sampling operations.8. Reagents and Materials8.1 Purity of ReagentsUse chemicals of at least 99 %purity for verification of
45、instrument performance (see Section11). Unless otherwise indicated, it is intended that all reagentsFIG. 1 Field Test ApparatusD7975 143conform to the specifications of the Committee on AnalyticalReagents of the American Chemical Society where suchspecifications are available.4Other grades may be us
46、ed, pro-vided it is first ascertained that the reagent is of sufficient purityto permit its use without lessening the accuracy of thedetermination.8.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water as definedby Type II in Specification D1193.8
47、.2.1 The chemicals in 8.3.1, 8.3.2, and 8.3.3 are suggestedfor verification of instrument performance (see Section 11),based on the air saturated reference fuels analyzed in the TestMethod D5191 2003 inter-laboratory study (ILS)5(see Table1). Ptot used in Test Method D5191 is equivalent to VPCR4-F(3
48、7.8C) used in this test method. Table 1 identifies theaccepted reference value (ARV) and uncertainty limits, as wellas the acceptable testing range for each of the reference fuelslisted.8.2.2 The chemicals in 8.4.1 and 8.4.2 are suggested for useas rinsing solvents capable of cleaning the measuring
49、chamber,the valves and the inlet and outlet tubes.8.3 Verification Fluids:8.3.1 2,2-Dimethylbutane, (Warning2,2-dimethylbutaneis flammable and a health hazard.)8.3.2 2,3-Dimethylbutane, (Warning2,3-dimethylbutaneis flammable and a health hazard.)8.3.3 Pentane, (WarningPentane is flammable and ahealth hazard.)8.4 Solvents:8.4.1 Toluene, (WarningToluene is flammable and ahealth hazard.)8.4.2 Acetone, (WarningAcetone is flammable and ahealth hazard.)8.5 Silicon-based or perfluorocarbon based lubricant is rec-ommended for hyd
