1、Designation: D1837 17Standard Test Method forVolatility of Liquefied Petroleum (LP) Gases1This standard is issued under the fixed designation D1837; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A numbe
2、r 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 is a measure of the relative purity ofthe various types of liquefied petroleum (LP) gases and helpsto ensure suitable vola
3、tility performance. The test results, whenproperly related to vapor pressure and density of the product,can be used to indicate the presence of butane and heaviercomponents in propane-type LP-gas, and pentane and heaviercomponents in propane-butane and butane-type fuels. Thepresence of hydrocarbon c
4、ompounds less volatile than those ofwhich the LP-gas is primarily composed is indicated by anincrease in the 95 % evaporated temperature.1.2 When the type and concentration of higher boilingcomponents is required, chromatographic analysis should beused.1.3 The values stated in SI units are to be reg
5、arded as thestandard.1.3.1 ExceptionThe non-SI values are provided for infor-mation only.1.4 WARNINGMercury has been designated by manyregulatory agencies as a hazardous material that can causecentral nervous system, kidney and liver damage. Mercury, orits vapor, may be hazardous to health and corro
6、sive tomaterials. Caution should be taken when handling mercury andmercury containing products. See the applicable product SafetyData Sheet (SDS) for details and EPAs websitehttp:/www.epa.gov/mercury/faq.htmfor additional information.Users should be aware that selling mercury and/or mercurycontainin
7、g products into your state or country may be prohib-ited by law.1.4.1 Note that thallium in a mercury-thallium thermometeris also a hazardous material.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
8、 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Documents2.1 ASTM Standards:2D96 Test Method for Water and Sediment in Crude Oil byCentrifuge Method (Field Procedure) (Withdrawn 2000)3D1796 Test Met
9、hod for Water and Sediment in Fuel Oils bythe Centrifuge Method (Laboratory Procedure)E1 Specification for ASTM Liquid-in-Glass Thermometers3. Summary of Test Method3.1 Refrigerate the sample by means of a cooling coil andcollect 100 mL of liquid in a weathering tube. Allow toevaporate (“weather”) a
10、t ambient pressure under specifiedconditions that approximate a single plate distillation. Measurethe observed temperature when 5 mL of liquid test portionremains. Correct this observed temperature for barometricpressure and thermometer ice point error, and report as the95 % evaporation temperature.
11、4. Significance and Use4.1 Volatility, expressed in terms of the 95 % evaporatedtemperature of the product, is a measure of the amount of leastvolatile components present in the product. Coupled with avapor pressure limit, it serves to ensure essentially single-component products in the cases of com
12、mercial grades ofpropane and butane. When volatility is coupled with a vaporpressure limit which has been related to density, as in the caseof the commercial PB-mixture, the combination serves toassure essentially two component mixtures for such fuels.When coupled with a proper vapor pressure limit,
13、 this mea-surement serves to assure that special-duty propane productswill be composed chiefly of propane and propylene and thatpropane will be the major constituent.5. Apparatus5.1 Weathering TubeA centrifuge tube, cone-shaped, con-forming to the dimensions given in Fig. 1 and made of1This test met
14、hod is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.H0 on Liquefied Petroleum Gas.Current edition approved Jan. 1, 2017. Published February 2017. Originallyapproved in 1961. Last previous edition a
15、pproved in 2011 as D1837 11. DOI:10.1520/D1837-17.2For 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.3The last a
16、pproved version of this historical standard is referenced onwww.astm.org.*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 StatesNOTICE: This standard has either been superseded
17、and replaced by a new version or withdrawn.Contact ASTM International (www.astm.org) for the latest information1thoroughly annealed heat-resistant glass.4The shape of thelower tip of the tube is especially important. The taper shall beuniform and the bottom shall be rounded as shown in Fig. 1.The tu
18、bes shall comply in wall thickness to ASTM centrifugetube requirements (Note 1). The graduation tolerances aregiven in Table 1.NOTE 1Requirements for centrifuge tubes appear in Test MethodsD96 and D1796.5.2 Tube SupportMeans shall be provided for supportingthe weathering tube by its neck in a vertic
19、al position.5.3 Water Bath (for use in tests on butane and propane-butane mixture types of liquefied petroleum gas only). Ashallow container filled with clean water having a maintainedtemperature ranging from 15 C to 21 C (60 F to 70 F) anda depth of 38 mm (112 in.).5.4 ThermometerASTM Armored Weath
20、ering Test Ther-mometer having a range from 50 C to 5 C (58 F to 41 F)and conforming to the requirements for Thermometer 99C92(99F86) as prescribed in Specification E1. Do not remove thearmor from the thermometer.5.5 BarometerA pressure measuring device capable ofmeasuring local station pressure wit
21、h an accuracy of 0.1 kPa(1 mm Hg) or better, at the same elevation relative to sea levelas the apparatus in the laboratory. (WarningDo not takereadings from ordinary aneroid barometers, such as those usedat weather stations and airports, since these are precorrected togive sea level readings.)5.6 Sa
22、mpling Precooling Equipment:5.6.1 Cooling VesselAny suitable wide-mouthed metalcontainer or Dewar flask at least 64 mm (212 in.) in insidediameter by 292 mm (1112 in.) deep.5.6.2 Cooling CoilApproximately 6 m (20 ft) of 4.8 mm(316 in.) outside diameter soft copper tubing, wound around ahollow mandre
23、l at least 54 mm (218 in.) in outside diameter,with adjacent turns touching. Run the lower end of the tube upthrough the center of the mandrel before winding so that thefinished coil will fit snugly inside the cooling vessel. Whenassembled, the top of the coil shall be at least 25 mm (1 in.)below th
24、e top of the cooling vessel and the open ends of thecoil shall not be more than 100 mm (4 in.) above. Connect thedownstream end of the coil to a 3.2 mm (18 in.) needle valvehaving an outlet connection not more than 76 mm (3 in.) long(see Fig. 2).5.6.3 PrecoolantThis may be the liquefied petroleum ga
25、sfrom the same container from which a sample is to be taken.Other refrigerants having a boiling point lower than the initialboiling point of the sample may be used. Use a nonflammableprecoolant if required.5.7 CharcoalFour grains of activated charcoal, approxi-mately 6 mesh to 14 mesh in size, are r
26、equired. The four grainsshall be similar in size (Note 2).4Borosilicate glass has been found satisfactory for this purpose.NOTE 1For graduation tolerances see Table 1.FIG. 1 Weathering TubeTABLE 1 Weathering Tube Graduation TolerancesRange, mLScaleDivision, mLLimit ofError, mL0.0 to 0.1 0.05 0.020.1
27、 to 0.3 0.05 0.030.3 to 0.5 0.05 0.050.5 to 1.0 0.1 0.051.0to3.0 0.1 0.13.0to5.0 0.5 0.25.0 to 25.0 1.0 0.525.0 to 100.0 1.0 1.0D1837 172NOTE 2Grains of charcoal are used as a boiling aid which reduces thetendency for the propane or butane to overflow the weathering tube as thepropane or butane evap
28、orates.6. Hazards6.1 Note that there is a significant fire hazard from LPGvapors, and since the boiling point of LPG can be as low as41 C, there is a risk of freezing “burns.” Take appropriatesafety precautions to prevent ignition or fire, and wear suitableprotective equipment to protect against ski
29、n contact with liquidor vaporizing LPG.6.2 When using a cooling bath of dry ice and a hydrocarbonsolvent, be aware that the bath can bump or splatter coldliquid when LPG is passed through the tubing.7. Procedure7.1 Positioning the ThermometerAdd water to the 5 mLline of the weathering tube. Add two
30、grains of charcoal. Insertthe armored thermometer as low as possible into the weather-ing tube. Observe and record the water level in the tube.Remove and discard the water and charcoal and clean and drythe weathering tube.7.2 Obtaining a Test Portion:7.2.1 Fill the cooling vessel with the precoolant
31、 so as tocover the cooling coil.7.2.2 The source of the sample (test portion) may be aprocess or delivery line, or a sample cylinder, taking care toobtain a liquid sample.7.2.3 Attach the inlet of the cooling coil to the source fromwhich the sample is to be taken with a short line connection of6.4 m
32、m (14 in.) pipe (or larger), having a sampling valve largeenough to prevent vaporization of the material due to the dropin pressure across the valve seat.7.2.4 Purge the sampling line and cooling coil by openingboth the sampling valve and the 3.2 mm (18 in.) needle valveon the downstream end of the
33、cooling coil.7.2.5 Fill the weathering tube with the sample flowingthrough the cooling coil.7.2.6 Empty this first sample.7.2.7 Add two grains of similar-sized charcoal as was usedin 7.1, and then refill the weathering tube to the 100 mL markwith fresh liquid sample passing through the cooling coil.
34、7.3 Placement of ThermometerCarefully insert the pre-cooled armored thermometer into the centrifuge tube, to thesame position as in 7.1, and center it in the tube by means ofa slotted cork. Take all 5 % residue readings at the levelestablished in 7.1.NOTE 3Inadequate precooling of the sample will re
35、sult in excessivevaporization and loss of light components from the sample collected in theweathering tube. This results in proportionally more of the higher boilingcomponents in the sample in order to collect 100 mL of liquid.As a result,the test is made more severe, with a higher reported 95 % eva
36、porationtemperature, which is on the conservative side.7.4 Weathering Butane and Propane-Butane Mixture Typesof Liquefied Petroleum Gas ProductsWhen the temperatureof the sample is below 12 C (10 F), allow it to weather inthe atmosphere until the temperature has reached 12 C(10 F). At this point, pl
37、ace the weathering tube, with thearmored thermometer still in place, in the water bath in avertical position, submerging it to the 112 mL mark, and allowthe contents to weather.7.5 Weathering Propane-Type Liquefied Petroleum GasProductsAllow the sample to weather in the atmosphere,taking care to dis
38、turb the frost on the tube as little as possible.An acetone or alcohol swab may be used to remove frostsufficient to permit reading of the temperature.7.6 Reading of TemperatureWhen the liquid level in theweathering tube, with the armored thermometer still in place,corresponds to the level previousl
39、y determined in 7.1, read andrecord the temperature of the sample in accordance with 7.4and 7.5.7.7 Temperature CorrectionFollowing the final tempera-ture reading (7.6), remove the armored thermometer from theweathering tube and place it in a bath of finely crushed ice upto the immersion point. Obse
40、rve the reading of the thermom-eter when a constant reading is obtained. If the thermometerreading is less than 0 C (32 F), add the fraction of a degreeit is low to the final test reading. If the thermometer reading ismore than 0 C (32 F), subtract the fraction of a degree that itis high from the fi
41、nal test reading. If the thermometer readingvaries more than 0.5 C (1 F), the test result is invalid. Repeatthe procedure using an accurate thermometer.NOTE 1The coils in the drawing are extended for clarity. Noteadditional detailed requirements in 5.6.2.FIG. 2 Precooling EquipmentD1837 173NOTE 4A h
42、igh reading of the thermometer when it is placed in iceusually indicates that there is a break in the mercury-thallium thread. Thiscan be corrected by warming the thermometer gently in a warm water bathto drive the break upward into the expansion chamber at the top of thethermometer. While the mercu
43、ry-thallium is continuous in the upperchamber, tap the bottom of the thermometer on a hard, but cushionedsurface, to join the liquid into a continuous thread. A low reading in iceusually indicates that some of the liquid has remained in the expansionchamber. To correct this, allow the thermometer to
44、 warm so the liquidenters the chamber and tap as previously instructed.8. Interpretation of Results8.1 Correct the thermometer reading at the 95 % boilingpoint (5 % residue) for the thermometer error (7.7).8.2 Correct the observed temperature for the thermometererror from the observed atmospheric pr
45、essure in kilopascals(kPa) (millimetres of mercury) to a base barometric pressure of101 kPa (760 mm).8.3 In the weathering test for propane, add 0.3 C (0.6 F) tothe corrected temperature for each 1.3 kPa (10 mm Hg) that thetest is conducted below 101 kPa (760 mm) pressure, or subtract0.3 C (0.6 F) f
46、rom the observed temperature for each 1.3 kPa(10 mm Hg) that the test is conducted above 101 kPa(760 mm).8.4 In the weathering test for butane and propane-butanemixtures, add 0.4 C (0.7 F) to the corrected temperature foreach 1.3 kPa (10 mm Hg) that the test is conducted below101 kPa (760 mm) pressu
47、re, or subtract 0.4 C (0.7 F) fromthe observed temperature for each 1.3 kPa (10 mm Hg) that thetest is conducted above 101 kPa (760 mm).9. Report9.1 Report the corrected 95 % boiling point temperature to0.1 C, and reference this test method.10. Precision and Bias10.1 The following criteria should be
48、 used for judging theacceptability of results (95 % confidence):10.1.1 RepeatabilityThe difference between two test re-sults obtained by the same operator with the same apparatusunder constant operating conditions on identical test materialswould in the normal and correct operation of the test metho
49、d,exceed the following value only in one case in twenty:0.6 C (1.0 F)10.1.2 ReproducibilityThe difference between two singleand independent results obtained by different operators work-ing in different laboratories on identical test material would inthe long run, in the normal and correct operation of the testmethod, exceed the following value only in one case in twenty:1.0 C (1.7 F) for butane and propane-butane mixtures,and1.3 C (2.3 F) for propane10.2 BiasThe procedure in this test
