ASTM D4124-2001 Standard Test Methods for Separation of Asphalt into Four Fractions《沥青分离为四种馏分的标准试验方法》.pdf

1、Designation: D 4124 01Standard Test Methods forSeparation of Asphalt into Four Fractions1This standard is issued under the fixed designation D 4124; 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 These test methods cover the separation of four definedfractions from petroleum asphalts. The four fractions aredefined as saturates, napht

3、hene aromatics, polar aromatics, andnC7-asphaltenes. These methods can also be used to isolatesaturates, naphthene aromatics, and polar aromatics fromdistillate products such as vacuum gas oils, lubricating oils, andcycle stocks. These distillate products usually do not containasphaltenes.1.2 The va

4、lues stated in SI units are to be regarded as thestandard.1.3 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-priate safety and health practices and determine the applica-bil

5、ity of regulatory limitations prior to use. Specific precau-tionary statements are given in Section 8 and 15.2. Referenced Documents2.1 ASTM Standards:C 670 Practice for Preparing Precision and Bias Statementsfor Test Methods for Construction Materials2C 802 Practice for Conducting an Interlaborator

6、y Test Pro-gram to Determine the Precision of Test Methods forConstruction Materials2D 140 Practice for Sampling Bituminous Materials3D 3279 Test Method for n-Heptane Insolubles32.2 Other Documents:Manual on Hydrocarbon Analysis43. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1

7、asphaltenes or n-heptane insolublesinsoluble mat-ter that can be separated from asphalt following digestion ofthe asphalt in n-heptane under the specified conditions in thesetest methods.3.1.2 naphthene aromaticsmaterial that is adsorbed oncalcined CG-20 alumina in the presence of n-heptane, anddeso

8、rbed by toluene, after removal of the saturates under theconditions specified.3.1.3 petrolenesthe n-heptane-soluble matter recoveredfollowing separation of the asphaltenes from the digestedmixture under the specified conditions in these test methods.3.1.4 polar aromaticsmaterial desorbed from calcin

9、edCG-20 alumina absorbent, after the saturates and naphthenearomatics have been removed, using toluene and trichloroeth-ylene eluants under the conditions specified.3.1.5 saturatesmaterial that, on percolation in a n-heptaneeluant, is not absorbed on calcined CG-20 alumina absorbentunder the conditi

10、ons specified.METHOD A4. Summary of Test Method4.1 The sample containing the four defined fractions is firstseparated into n-heptane-insoluble asphaltenes and then-heptane-soluble petrolenes. Petrolenes are then adsorbed oncalcined CG-20 alumina and further fractionated into thesaturate, naphthene a

11、romatic and polar aromatic fractions bydownward solvent elution in a glass chromatographic column.Eluted fractions are recovered by solvent removal prior to finalweighing. The three eluted fractions plus the n-heptane-precipitated (nC7) asphaltenes comprise the four fractionsdefined in Section 3.5.

12、Significance and Use5.1 This test method separates asphalts into four well-defined fractions. Analysis of these fractions can be used toevaluate asphalt composition. For example, one can comparethe ratios of the fractions with other asphalt systems to evaluateprocessing and aging parameters that rel

13、ate to performanceproperties of the asphalt.6. Apparatus and Materials6.1 Glass Chromatographic Column,51000 mm long and31 mm in inside diameter with features as specified in Fig. 1.6.2 UtilitiesSteam bath, vacuum source, nitrogen source,and drying oven (Rotavapor solvent stripper and electricheatin

14、g mantles optional).1This test method is under the jurisdiction of ASTM Committee D04 on Roadand Paving Materials and is the direct responsibility of Subcommittee D04.47 inMiscellaneous Asphalt Tests.Current edition approved Aug. 10, 2001. Published October 2001. Originallypublished as D 4124 82. La

15、st previous edition D 4124 97.2Annual Book of ASTM Standards, Vol 04.02.3Annual Book of ASTM Standards, Vol 04.03.4Available from ASTM as PCN 03-332030-12.5Can be custom-made by any professional glassblower.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 1942

16、8-2959, United States.6.3 Beakers, graduated; Erlenmeyer flasks, 400-mL; Round-Bottom Flasks, 500-mL, if Rotavapor is used for solventremoval.6.4 Funnels, two, pressure-equalizing, 500-mL.6.5 Funnel, Bchner, 12.5-cm.6.6 Funnel, Separatory, 1-L, TFE-fluorocarbon stopcockpreferred.6.7 Flask, Suction,

17、2-L.6.8 Flask, Erlenmeyer, 2-L, with foil-covered rubber stop-per.6.9 Rinse Squeeze Bottle, 0.5 L size, polyethylene or TFE-fluorocarbon.6.10 Evaporating Dishes, porcelain, 16 and 28-cm.6.11 Analytical Balance.6.12 Filter Paper, slow to medium filter speed, qualitativegrade, 12.5-cm diameter.6.13 Ex

18、traction Thimble, 33/94 mm.6.14 Stirrer, air-powered.6.15 Stirring Rod with suitable foil-covered rubber stopperto fit 2-L Erlenmeyer flask.FIG. 1 Chromatographic Column for Separation of Asphalt by Elution-Adsorption (Method A or B)D41240126.16 Glass Wool, borosilicate.6.17 Electric Heat Lamp or Ho

19、t Plate.7. Reagents and Absorbent7.1 Alumina,6CG-20 chromatographic grade, calcined at413C for 16 h and stored in an evacuated desiccator or airtightbottles.7.2 n-Heptane (Note 1), 99 minimum mol % (pure grade).NOTE 1n-Heptane should be totally free of moisture. Pretreatment ofn-heptane with 5A mole

20、cular sieves or by refluxing over calcium hydridemay be necessary to remove residual moisture in the solvent.7.3 Methanol, anhydrous, reagent grade.7.4 Toluene, reagent grade.7.5 Trichloroethylene, boiling point 86.5 to 87.5C.8. Safety Precautions8.1 Most organic solvents used in these methods are f

21、lam-mable and to some degree toxic. Reference should be made toMaterial Safety Data Sheets available from the supplier. Thesesolvents should be handled with care and only in well-ventilated areas. All working areas should be kept free ofsparks, flames, or other sources of high temperature.9. Samplin

22、g and Sample Preparation9.1 Bulk samples taken in accordance with Practice D 140shall be representative and free of foreign substances. Samplesfor testing in 10.1.1 can be transferred by chilling to facilitatefracturing the sample or by heating the sample until it hasbecome sufficiently fluid to pou

23、r. Caution: In no case shall thesamples be heated more than 110C above the expectedsoftening point. Transfer of a representative portion from thebulk sample to a smaller container may be necessary fordetermination of sample mass to the nearest 0.01 g in 10.1.1.10. Procedure10.1 Separation of Asphalt

24、enes and Petrolenes:10.1.1 Weigh to the nearest 0.01 g and place into a 2-LErlenmeyer flask a sufficient quantity of asphalt (Note 2) sothat it yields about 10 g of petrolenes as indicated by thefollowing equation:Sample mass, g 5 1000/1002% asphaltenes (1)For paving asphalts, this would be 11 to 13

25、 g of asphalt andslightly more for airblown asphalts. Unless the asphalt is ingranular form, warm the flask gently with a heat lamp or hotplate and disperse the asphalt over the bottom and lower sidesof the flask before adding the n-heptane solvent in the ratio of100 mL of solvent per1gofsample.NOTE

26、 2The quantity of asphalt required for 10 g of petrolenes caneasily be predetermined in accordance with Test Method D 3279.10.1.2 Install an air-powered stirrer assembly into the flaskprior to placing flask and its contents on a steam bath. Thestirring rod should rotate inside a foil-covered rubber

27、stopperthat is used to seal the Erlenmeyer flask to reduce theevaporation of n-heptane. Maintain the solvent temperaturenear its boiling point and stir the contents of the flask at amoderate rate until there is no visual evidence of undispersedasphalt adhering to the sides of the flask. Begin timing

28、 andcontinue stirring for an additional 1 h. Normally1hissufficient time for straight reduced asphalts but for airblown orchemically modified asphalts the digestion time should beextended to 1.5 h. After digestion, remove the flask and stirringassembly from the steam bath. Rinse the stirring assembl

29、y as itis removed from the flask with n-heptane from a squeezebottle. Cover the flask with a foil-covered rubber stopper andset aside overnight at ambient temperature so the precipitatedasphaltenes can settle to the bottom of the flask.10.1.3 Set up a 12.5-cm diameter Bchner funnel appropri-ately fi

30、tted with a slow to medium filter speed, qualitative-grade filter paper and a 2-L suction flask. The 1-L separatoryfunnel should be suspended about 25 mm above the center ofthe filter paper.10.1.4 Decant as much of the clear heptane-petrolene solu-tion as possible from the mixture prepared in 10.1.2

31、 and placeit directly in the separatory funnel.10.1.5 Wet the filter paper in the Bchner funnel withn-heptane from a squeeze bottle and apply sufficient suction tothe flask to secure the filter paper firmly to the funnel surfacebefore beginning the filtration step. Add petrolene solutionfrom the sep

32、aratory funnel at a closely controlled rate and insuch a manner that all of the filtering takes place in the centerof the paper. The filter paper should be wetted periodicallyfrom the squeeze bottle to ensure a tight seal with the funnelsurface. After the filtering is completed, it is advisable to e

33、mptyor replace the suction flask before proceeding with the finalphase of filtration process.10.1.6 Test the filtrate from 10.1.5 for insolubles by placinga drop of the filtrate on a filter paper. Refilter if a ring appears.10.1.7 Transfer the contents remaining in the Erlenmeyerflask directly to th

34、e Bchner funnel, using additional solventfrom the squeeze bottle and repeatedly wash the asphaltenecake until the filtrate becomes colorless. Take care to ensurethat no insolubles creep over the edges of the filter paper intothe filtrate. Next, transfer the filter paper and its contents to a500-mL b

35、eaker and add 150 mL of n-heptane. Heat thecontents in the beaker for about 30 min with occasional stirringto remove n-heptane-soluble materials entrained in the asphalt-ene cake. Filter the hot solution through the same Bchnerfunnel fitted with a tared, fresh piece of filter paper, using theprescri

36、bed procedures. Continue washing the asphaltene cakeuntil the filtrate is colorless. Test the filtrate for insolubles as in10.1.6 and repeat this task if a ring appears.10.2 Solvent Evaporation:10.2.1 Transfer the asphaltene cake on the filter papers(10.1.5 and 10.1.7) to a 16-cm evaporating dish an

37、d dry in a104C oven until a constant mass is achieved. Record the netmass of asphaltenes recovered and store if desired in ascrew-cap bottle.6F-20 grade alumina originally referenced in this standard is no longer availablefrom Alcoa, the manufacturer. The CG-20 alumina now referenced is the replace-

38、ment supplied by the manufacturer. The test results are very sensitive to the qualityand grade of alumina used. Currently there is no data available indicating differencein test results between the F-20 and the CG-20 alumina. If users of this method havehistorical data, it may be useful to do a comp

39、arison between data derived from testsusing the two aluminas.D412401310.2.2 Heptane can be removed from filtrates containingpetrolenes (10.1.5 and 10.1.7) using standard laboratory pro-cedures. Concentrate the petrolene solution to about 50 mL andthen transfer the concentrate to a 150-mL beaker. Suf

40、ficientfluidity should remain in the petrolene concentrate to permiteasy transfer of concentrate to a chromatographic column forsubsequent separation into the three defined fractions.10.3 Separation of Petrolene Concentrate into Three De-fined Fractions:10.3.1 Set up the chromatographic column with

41、appurte-nances as shown in Fig. 1. Place a concave filter pad, cut fromthe bottom of an extraction thimble (6.13), on the bottom of thecolumn, and follow by 25 mm of a glasswool plug. Add 450 gof calcined alumina while gently tapping the column with arubber-coated object. Place a glass wool plug on

42、top of thealumina bed, add 50 mL of n-heptane to prewet the column,and proceed immediately to 10.3.2.10.3.2 Transfer the petrolene concentrate from 10.2.2 to thecolumn, using minimum amount of n-heptane. Start addition ofeluants with 200 mL of n-heptane (see Table 1) from theequal-pressure funnel at

43、 a drip rate of about 5 mL/min (Fig. 1);simultaneously collect eluate at the rate of 5 6 1 mL/min in thereceiving funnel; and subsequently drain the eluate into taredcontainers (weighed to 0.01 g) in accordance with the schedulein Table 1.10.3.2.1 Caution: At no time should the liquid level in theco

44、lumn be allowed to drop below the top of the alumina beduntil the final hold-up is removed.10.3.3 Add the new eluant to the column before the finaleluate cut from the previous eluant is taken. Based on earlierstudies, such procedure regulates fractionation, provided eluatecuts are taken in accordanc

45、e with the schedule in Table 1. Thisprocedure requires close attention, especially during the col-lection of the saturates and naphthene aromatics fractions. Thecut point between the naphthene aromatics and polar aromaticsfractions is more obvious and may be improved by eithercutting short or increa

46、sing the volume of this cut as observedby the descent of the black polar aromatic ring. The elutionvolume will vary with the composition of the feed, and the cutpoint should be made as the black ring reaches the bottom ofthe alumina bed. The naphthene aromatics fraction produces ayellow to deep red

47、color eluate whereas the polar aromaticseluate is almost black. The hold-up in the column is thatsolvent collected by gravity drainage at the end of the eluationprocess and should be essentially colorless.10.3.4 Recover the three fractions by solvent removal pro-cedures using standard laboratory pro

48、cedures and record thenet mass of each fraction.11. Calculation and Report11.1 Calculate the weight percent of the fractions, F,asthemass percent of the original samples as follows:F,%5 A/B! 3 100 (2)where:A = mass of the fraction, andB = mass of the sample.11.2 Report percentages to the nearest 0.1

49、 % mass.12. Precision and Bias12.1 Criteria for judging the acceptability of test resultsobtained by this test method are provided in Table 3. Data wereobtained from tests by seven rather than ten laboratories asrecommended in Practice C 802.12.2 Material and range covered are described in Table 3.These numbers represent the (1S) and (D2S) limits as de-scribed in Practice C 670. This precision statement applies onlyto the ranges covered in the precision study. The results of testswhich are far outside the ranges studied may have differentprecision values.METHOD BSH