1、Designation: D2158 16a1Standard 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 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.1NOTEThe IP designation was removed editorially in February 2018.1. Scope*1.1 This test method covers the determination of extraneousmaterials weatherin
3、g above 38 C that are present in liquefiedpetroleum 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
4、this test method has been used to verifycleanliness 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, cou
5、ld be required for some applica-tions.1.4 The 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 u
6、ser of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established i
7、n the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D96 Test Method for Water and Sediment in Crude Oil byCentrifuge Method
8、 (Field Procedure) (Withdrawn 2000)3D1796 Test Method for Water and Sediment in Fuel Oils bythe Centrifuge Method (Laboratory Procedure)D1835 Specification for Liquefied Petroleum (LP)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 AS
9、TM Thermom-eters with Low-Hazard Precision LiquidsE2877 Guide for Digital Contact 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 speci
10、fied conditions on absorbentpaper.3.1.2 residue, nthe volume, measured to the nearest0.05 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 o
11、f solvent with any residue remaining in the centrifugetube at the conclusion of the first step in this test method.1This 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
12、Petroleum Gas.Current edition approved Dec. 15, 2016. Published January 2017. Originallyapproved in 1963. Last previous edition approved in 2016 as D2158 16. DOI:10.1520/D2158-16AE01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.
13、org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary 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,
14、 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides an
15、d Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.14. 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 andrecord
16、ed.4.2 To dissolve any residue, 10 mLof solvent is added to thecentrifuge 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 isobser
17、ved and recorded.5. Significance and Use5.1 Control over the residue 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
18、 over can foul regulating equipment.Residues that remain in vapor-withdrawal systems willaccumulate, 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
19、 as rust, scale or dirt caninterfere with this test method, which is not intended forrepresentative 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 giv
20、en in Fig. 1. The first 0.5 mL shall be graduatedin 0.05 mL increments. The shape of 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 to
21、lerances, based on air-free water at 20 C, aregiven in Table 1. Detailed requirements 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 diame
22、ter, andassembled in a suitable cooling bath. (See Fig. 2 as anexample.)7.2.1 Mechanical refrigeration is permitted provided thatthe coolant temperature is below 43 C. If dry ice is used, anon-glass dewar or vessel is recommended.7.3 Syringe, 2 mL graduated in 0.1 mL and equipped with aneedle 200 mm
23、 6 5 mm long.The needle may be either 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 Measuri
24、ng Device, that is intrinsicallysafe, 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 d
25、igital contact thermometer with 0.5 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 c
26、entrifuge tubewith the hand.7.5 Absorbent 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
27、 6 2 C.7.8 Copper Wire, 1 mm to 2 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 mee
28、ts therequirements of 10.2.8.1.1 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 bottl
29、e forseveral days contaminates the 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 fre
30、ezing “burns.” Take appropriatesafety 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 samplecyl
31、inder are also advised.9.3 When using 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 Verifica
32、tion of cleanliness of glassware 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.D2158 16a1210.2.3 Fill the syringe or equivalent liquid dispensing de-vice (see 7.3) with a
33、 portion of the solvent drawn from thecentrifuge 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 indiameter. The filter paper should be held level during thesolvent a
34、ddition. One method 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.
35、2 If no oil ring 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.FIG. 1 Cone-Shaped Centrifuge Tube, 203 mmTABLE 1 Centrifuge Tube Graduation Toleranc
36、esRange, mLScale, Division,mLLimit of Error,mL0.0 to 0.1 0.05 0.020.1 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 1.0D2158 16a1311. Procedure11.1 Residue Measurement:11.1.1 If the LPG sample is expected to be clean, with
37、 noresidues 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
38、with1.5 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
39、sampled 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 b
40、umping (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 amb
41、ient temperature 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 diese
42、l fuel components, 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.
43、See 11.4.11.1.7 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
44、a thin film 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 residu
45、e described 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 sat
46、isfactory. 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
47、such that 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
48、oil ring 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 mi
49、n on a new 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 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 t
