1、Designation: D2158 16aDesignation: 317/95(02)Standard Test Method forResidues in Liquefied Petroleum (LP) Gases1This standard is issued under the fixed designation D2158; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、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 determination of extraneousmaterials weathering above 38 C that are present in liquefiedp
3、etroleum gases. The extraneous materials will generally bedissolved in the LPG, but may have phase-separated in someinstances.1.2 Liquefied petroleum gases that contain certain anti-icingadditives can give erroneous results by this test method.1.3 Although this test method has been used to verifycle
4、anliness and lack of heavy contaminants in propane formany years, it might not be sensitive enough to protect someequipment from operational problems or increased mainte-nance. A more sensitive test, able to detect lower levels ofdissolved contaminants, could be required for some applica-tions.1.4 T
5、he values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.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-pri
6、ate 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Documents2.1 ASTM Standards:2D96 Test Method for Water and Sediment in Crude Oil byCentrifuge Method (Field Procedure) (Withdrawn 2000)3D1796 Test Method for Water and Sediment in Fu
7、el Oils bythe Centrifuge Method (Laboratory Procedure)D1835 Specification for Liquefied Petroleum (LP) GasesE1137 Specification for Industrial Platinum Resistance Ther-mometersE2251 Specification for Liquid-in-Glass ASTM Thermom-eters with Low-Hazard Precision LiquidsE2877 Guide for Digital Contact
8、Thermometers3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 oil stain observation, nthe volume of solvent-residue mixture required to yield an oil stain or ring thatpersists for 2 min under specified conditions on absorbentpaper.3.1.2 residue, nthe volume, measured to the near
9、est0.05 mL, of the residual material boiling above 38 C resultingfrom the evaporation of 100 mL of sample under the specifiedconditions of this test method.3.1.3 solvent-residue mixture, na mixture (solution) of10 mL of solvent with any residue remaining in the centrifugetube at the conclusion of th
10、e first step in this test method.4. Summary of Test Method4.1 A 100 mL sample of liquefied petroleum gas is weath-ered in a 100 mL centrifuge tube. The volume of residueremaining after heating the tube to 38 C is measured andrecorded.4.2 To dissolve any residue, 10 mLof solvent is added to thecentri
11、fuge tube. Small, measured volumes of solvent-residuemixture are deposited on an absorbent paper in a specifiedmanner. The appearance of the absorbent paper to which theresidue solution has been added in measured increments isobserved and recorded.5. Significance and Use5.1 Control over the residue
12、content (required by Specifica-tion D1835) is of considerable importance in end-use applica-tions of LPG. In liquid feed systems, residues can lead totroublesome deposits and, in vapor withdrawal systems, resi-dues that are carried over can foul regulating equipment.Residues that remain in vapor-wit
13、hdrawal systems will1This test method 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 Dec. 15, 2016. Published January 2017. Originallyapprove
14、d in 1963. Last previous edition approved in 2016 as D2158 16. DOI:10.1520/D2158-16A.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
15、page onthe ASTM website.3The last approved 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 StatesThis internati
16、onal standard was developed in accordance 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) Committ
17、ee.1accumulate, can be corrosive, and will contaminate subsequentproduct. Water, particularly if alkaline, can cause failure ofregulating equipment and corrosion of metals.6. Interferences6.1 Solid contaminants such as rust, scale or dirt caninterfere with this test method, which is not intended for
18、representative measurement of solid, undissolved contami-nants. However, the presence of solids in the centrifuge tubeshould be reported.7. Apparatus7.1 Centrifuge Tube, 100 mL graduated, conforming todimensions given in Fig. 1. The first 0.5 mL shall be graduatedin 0.05 mL increments. The shape of
19、the lower tip of the tubeis especially important. The taper shall be uniform and thebottom shall be rounded as shown in Fig. 1. Tubes shall bemade of thoroughly annealed heat-resistant glass. Volumetricgraduation tolerances, based on air-free water at 20 C, aregiven in Table 1. Detailed requirements
20、 for centrifuge tubesappear in Test Methods D96 and D1796.7.2 Cooling Coil and Cooling Bath, a minimum length of6 m of 5 mm to 7 mm outside diameter copper tubing wound toa diameter of 63.5 mm 6 1.5 mm outside diameter, andassembled in a suitable cooling bath. (See Fig. 2 as anexample.)7.2.1 Mechani
21、cal refrigeration is permitted provided thatthe coolant temperature is below 43 C. If dry ice is used, anon-glass dewar or vessel is recommended.FIG. 1 Cone-Shaped Centrifuge Tube, 203 mmD2158 16a27.3 Syringe, 2 mL graduated in 0.1 mL and equipped with aneedle 200 mm 6 5 mm long.The needle may be ei
22、ther a sharpneedle (ordinary medical syringe needle) or a safe, non-sharpsyringe needle to avoid a puncture hazard. Alternatively, anequivalent liquid dispensing device capable of delivering0.1 mL increments may be used, such as a 0.1 mL pipet.7.4 Temperature Measuring Device, that is intrinsicallys
23、afe, with accuracy equal to or better than liquid-in-glassthermometer ASTM S5C described in Specification E2251.Guide E2877 and Specification E1137 may be useful forselecting a digital contact thermometer.7.4.1 For routine testing, a general purpose thermometer ora digital contact thermometer with 0
24、.5 C subdivisions ordisplay resolution and a maximum error of 0.5 C may be used.NOTE 1When a thermometer or a water bath, or both, are notavailable, for example when conducting a field test, a satisfactoryalternative for screening purposes is to warm the tip of the centrifuge tubewith the hand.7.5 A
25、bsorbent Paper, white, at least 100 mm diameter.Medium grade or rapid filter paper has been found to besatisfactory. In this test method, the paper will be referred to as“filter paper.”7.6 Solvent Wash Bottle, typically polyethylene.7.7 Water Bath, controlled at 38 C 6 2 C.7.8 Copper Wire, 1 mm to 2
26、 mm diameter, at least 10 mmlonger than the centrifuge tubes height.7.9 Clamp, suitable for holding the centrifuge tube duringweathering.8. Reagents and Materials8.1 SolventHPLC-grade pentane or cyclopentane. An-other grade of solvent may be used provided that it meets therequirements of 10.2.8.1.1
27、Although pentane is the preferred solvent for use inthis test method, cyclopentane may be substituted for pentanewhenever the ambient temperature or altitude is too high toenable the convenient handling of pentane.8.1.2 Storage of solvent in a polyethylene wash bottle forseveral days contaminates th
28、e solvent. Therefore, do not useany solvent that has remained in a polyethylene wash bottle formore than one day.9. Hazards9.1 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 appropriatesa
29、fety precautions to prevent ignition or fire, and wear suitableprotective equipment to protect against skin contact with liquidor vaporizing LPG.9.2 Operators should wear a grounded antistatic wrist strap.The use of an antistatic floor mat and grounding the samplecylinder are also advised.9.3 When u
30、sing a cooling bath of dry ice and hydrocarbonsolvent, be aware that the bath can bump or splatter coldliquid when LPG is passed through the tubing.10. Preparation of Apparatus10.1 Wash all glassware that is to be used in the test in theselected solvent.10.2 Verification of cleanliness of glassware
31、and solvent.10.2.1 Add 10 mL of a new sample of solvent to thecentrifuge tube.10.2.2 Mark the center of the filter paper with a pencil orother non-pentane-soluble writing tool.10.2.3 Fill the syringe or equivalent liquid dispensing de-vice (see 7.3) with a portion of the solvent drawn from thecentri
32、fuge tube and direct 0.1 mL portions of the solvent to themark on the paper.10.2.3.1 The solvent is added in 0.1 mL increments toconfine the solvent ring to a circle about 30 mm to 35 mm inTABLE 1 Centrifuge Tube Graduation TolerancesRange, mLScale, Division,mLLimit of Error,mL0.0 to 0.1 0.05 0.020.
33、1 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 1.0NOTE 1Coils in the drawing are extended for clarity.FIG. 2 Precooling EquipmentD2158 16a3diameter. The filter paper should be held level during thesolvent addition. One me
34、thod is to place it on a 250 mLbeaker.10.2.4 Allow the solvent to evaporate for 2 min, and notethe persistence of an oil ring.10.2.4.1 The presence of an oil ring shall be observed byholding the dry filter paper between the eye and a brightincandescent light or strong daylight.10.2.4.2 If no oil rin
35、g appears after 1.5 mL of solvent hasbeen added, the solvent and glassware are satisfactory.10.2.4.3 The appearance of an oil ring indicates eitherimproperly cleaned glassware or contaminated solvent.11. Procedure11.1 Residue Measurement:11.1.1 If the LPG sample is expected to be clean, with noresid
36、ues or contaminants that could result in an oil stain, theprocedure may be performed without a cooling coil. However,if a residue or oil stain is detected using this screeningprocedure (that is, a residue is measured at greater than orequal to 0.05 mL in 11.1.7, or an oil stain is generated with1.5
37、mL of test solution in 11.2.4), the test shall be repeatedusing a cooling coil.11.1.2 Attach the cooling coil to the LPG sample source,cool the coil to below the boiling point of the sample, and flushthe coil and sampling line.11.1.3 Rinse and cool the centrifuge tube with the materialto be sampled
38、and then fill it to the 100 mL mark with arepresentative sample of LPG.11.1.4 Immediately insert the copper wire through a clean,slotted cork or a clean, loose-fitting plug of cotton or cleansingtissue in the mouth of the centrifuge tube. The wire helps toprevent superheating and resulting bumping (
39、erratic or exces-sive boiling), and the cork (or plug) will keep out air ormoisture while the sample is weathering.11.1.5 If more than 10 mL of the sample is lost because ofbumping, obtain a new sample and repeat the test.11.1.6 Allow the sample to weather, using artificial heatingif the ambient tem
40、perature or type of sample requires it. If,when weathering has ceased and the tube has reached ambienttemperature, a visible residue remains, place the tip of the tubein a water bath at 38 C for 5 min.NOTE 2Residues that are volatile at 38 C, such as most gasolinecomponents and lighter diesel fuel c
41、omponents, will evaporate at thistemperature and not contribute to residue by Test Method D2158.However, materials that have low vapor pressure at 38 C, such as higherboiling components of diesel fuel, lubricating oils, heavy greases andplasticizers, will remain and be measured as residues. See 11.4
42、.11.1.7 Record the volume of any remaining residue to thenearest 0.05 mL, and the presence of extraneous matter, ifobserved.11.1.8 Perform the oil stain observation described in 11.2even if there is no apparent or visible residue in the centrifugetube. Experience has shown that there can be a thin f
43、ilm of oilon the inner surface of the centrifuge tube that is difficult to seeand does not give a measurable volume, but can still give a ringor stain in the Oil Stain Observation procedure.11.2 Oil Stain Observation:11.2.1 Add sufficient solvent to the centrifuge tube contain-ing the residue descri
44、bed in 11.1.6 to restore the volume to10 mL. Add the solvent from the wash bottle and carefullywash down the sides of the tube. Stir well so that any residueat the bottom of the tube is dissolved uniformly in the solvent.Stirring with the syringe needle (see 7.3) or pipette has beenfound satisfactor
45、y. This mixture will be referred to as thesolvent-residue mixture.11.2.2 Mark the center of a clean white filter paper.11.2.3 Fill the syringe or equivalent liquid dispensing de-vice (see 7.3), and direct 1.5 mL of the solvent-residue mixtureat the center of the paper at an appropriate rate such tha
46、t thewetted circle is maintained at about 30 mm to 35 mm indiameter. If desired, steps 11.2.3 and 11.2.4 may be omitted,and the test continued according to 11.2.5.11.2.4 After directing the entire 1.5 mL of residue solutiononto the filter paper and at the end of a 2 min waiting period,if no oil ring
47、 persists when holding the dry filter paper betweenthe eye and a bright incandescent light or strong daylight,discontinue the test and go to 12.1.11.2.5 If a stain or ring is discernible, determine the volumeof the solvent-residue mixture at which the oil stain or ring firstpersists for 2 min on a n
48、ew filter paper by adding thesolvent-residue mixture in 0.1 mL increments, waiting 2 minafter each addition, and inspecting the paper for an oil stain atthe end of the 2 min period.11.2.6 Record the volume in millilitres of the solvent-residue mixture required to yield a persistent oil stain or ring
49、 asthe oil stain observation.11.2.7 Alternatively, if a product specification calls foradding a specified amount of solvent-residue mixture to thefilter paper, add the specified quantity in 0.1 mL increments,and report the result at the specified total amount.11.2.7.1 Specification D1835 specifies that 0.3 mL ofsolvent-residue mixture shall be deposited on the filter paper in0.1 mL increments.11.2.7.2 If there is no oil stain after the addition of 0.3 mLand a 2 min waiting period, report the result as “Pass.”11.2.7.3 If an oil stain is observed at 0.3 mL
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