1、Designation: D7060 12 (Reapproved 2014)Standard Test Method forDetermination of the Maximum Flocculation Ratio andPeptizing Power in Residual and Heavy Fuel Oils (OpticalDetection Method)1This standard is issued under the fixed designation D7060; the number immediately following the designation indi
2、cates the year oforiginal adoption or, in the case of 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 a procedure for qu
3、antifying themaximum flocculation ratio of the asphaltenes in the oil and thepeptizing power of the oil medium, by an automatic instrumentusing an optical device.1.2 This test method is applicable to atmospheric or vacuumdistillation residues, thermally cracked residue, intermediateand finished resi
4、dual fuel oils, containing at least 1 mass %asphaltenes. This test method has not been developed forasphalts.NOTE 1An optical probe detects the formation of flocculated as-phaltenes. The start of flocculation is interpreted when a significant andsustained increase in rate-of-change of signal, as mea
5、sured by the opticalprobe, ensures flocculation is in progress. The start of flocculation can bedetected unambiguously when the sample contains at least 1 % massasphaltenes as measured by Test Method D6560.NOTE 2This test method is applicable to products typical of Specifi-cation D396Grades 5L, 5H,
6、and 6, and Specification D2880Grades3-GT and 4-GT.1.3 This test method was evaluated in an interlaboratorystudy in the nominal range of 32 to 76 for the maximumflocculation ratio and in the nominal range of 36 to 95 forpeptizing power.NOTE 3The nominal range is determined by (min. sample meanReprodu
7、cibility) to (max. sample mean + Reproducibility).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 theresponsibil
8、ity 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 Standards:2D396 Specification for Fuel OilsD2880 Specification for Gas Turbine Fuel OilsD4057 Practice for Ma
9、nual Sampling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD4870 Test Method for Determination of Total Sediment inResidual FuelsD6300 Practice for Determination of Precision and BiasData for Use in Test Methods for Petroleum Products andL
10、ubricantsD6560 Test Method for Determination ofAsphaltenes (Hep-tane Insolubles) in Crude Petroleum and Petroleum Prod-uctsD6792 Practice for Quality System in Petroleum Productsand Lubricants Testing Laboratories3. Terminology3.1 Definitions:3.1.1 asphaltenes, n(rarely used in the singular), in pet
11、ro-leum technology, represent an oil fraction that is soluble in aspecified aromatic solvent but separates upon addition of anexcess of a specified paraffinic solvent.3.1.1.1 DiscussionIn this test method, the aromatic sol-vent is 1-methylnapthalene, and the paraffinic solvent isn-hexadecane.3.1.2 c
12、ompatibility, n of crude oils or of heavy fuel oils,the ability of two or more crude oils or fuel oils to blendtogether within certain concentration ranges without evidenceof separation, such as the formation of multiple phases.3.1.2.1 DiscussionIncompatible heavy fuel oils or crudeoils, when mixed
13、or blended, result in the flocculation orprecipitation of asphaltenes. Some oils may be compatible1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.14 on Stability and Cleanliness o
14、f Liquid Fuels.Current edition approved Dec. 1, 2014. Published February 2015. Originallyapproved in 2004. Last previous edition approved in 2012 as D7060 12. DOI:10.1520/D7060-12R14.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.
15、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 States1within certain concentration ranges in specific mixtures, butinc
16、ompatible outside those ranges.3.1.3 flocculation, n of asphaltenes from crude oils orheavy fuel oils, the aggregation of colloidally dispersed as-phaltenes into visibly larger masses which may or may notsettle.3.1.4 peptization, n of asphaltenes in crude oils or heavyfuel oils, the dispersion of as
17、phaltenes to produce a colloidaldispersion.3.1.5 stability reserve, n in petroleum technology, theproperty of an oil to maintain asphaltenes in a peptized stateand prevent flocculation of the asphaltenes.3.1.5.1 DiscussionAn oil with a low stability reserve islikely to undergo flocculation of asphal
18、tenes when stressed (forexample, extended heated storage) or blended with a range ofother oils. Two oils each with a high stability reserve are likelyto maintain asphaltenes in a peptized state and not lead toflocculation when blended together.3.2 Definitions of Terms Specific to This Standard:3.2.1
19、 critical cetane dilution, nnumber of millilitres ofcetane with which1gofundiluted sample can be diluted untilit just does not flocculate the asphaltenes.3.2.2 critical dilution, nnumber of millilitres of1-methylnaphthalene and cetane with which1gofundilutedsample can be diluted until it just does n
20、ot flocculate theasphaltenes.3.2.2.1 DiscussionThe number of millilitres of1-methylnaphthalene and cetane is variable and depends on theratio of sample to 1-methylnaphthalene at the starting point andthe sample type.3.2.3 flocculation ratio, npercentage by volume of1-methylnaphtalene in a mixture of
21、 1-methylnaphthalene andcetane.3.2.4 flocculation ratio at critical dilution, npercentage byvolume of 1-methylnaphthalene in a mixture of1-methylnaphthalene and cetane at the inflection point.3.2.5 inflection point, nlast step during the titration withcetane, where flocculation of asphaltenes is not
22、 detected by theoptical probe as a significant and sustained increase in rate-of-change of signal.3.2.6 maximum flocculation ratio, nof asphaltenes, mini-mum required solvency power, expressed as percentage byvolume of 1-methylnaphthalene in a mixture of1-methylnaphthalene and cetane, to keep the as
23、phaltenes in acolloidal solution.3.2.6.1 DiscussionMaximum flocculation ratio is the floc-culation ratio at extrapolated infinite dilution of the sample.3.2.7 oil medium, nthat portion of a sample of heavy fueloil or crude oil that surrounds and colloidally disperses theasphaltenes.3.2.7.1 Discussio
24、nFor purposes of this test method, an oilsample is considered to be composed of an oil medium(sometimes called an oil matrix or maltenes) and asphaltenes.3.2.8 peptizing power, navailable solvency power, ex-pressed as percentage by volume of 1-methylnaphthalene in amixture of 1-methylnaphthalene and
25、 cetane, to keep as-phaltenes in a colloidal solution.3.2.9 reciprocal dilution, ndilution ratio of sample insolvent mixture of 1-methylnaphthalene and cetane.3.3 Symbols:FRmax= maximum flocculation ratioFRx= flocculation ratio at critical dilutionPo = peptizing powerXmin = critical cetane dilutionX
26、c = critical dilution4. Summary of Test Method4.1 Six portions of the sample are diluted in various ratioswith 1-methylnaphthalene. Each solution is inserted into theautomatic apparatus, and titrated with cetane until flocculationof asphaltenes is detected by the optical probe. The first twosolution
27、s are titrated with cetane in coarse determinations inwhich the flocculation ratio is decreased in 5 % steps. Thecoarse determinations help to establish suitable starting valuesfor the fine determinations, in which the flocculation ratio isdecreased in 1 % steps. The four flocculation ratios at crit
28、icaldilution, measured during the fine determinations, are used tocalculate the maximum flocculation ratio of the samplesasphaltenes and the peptizing power of the samples oilmedium.5. Significance and Use5.1 Asphaltenes are naturally occurring materials in crudepetroleum and petroleum products cont
29、aining residual mate-rial. The asphaltenes are usually present in colloidalsuspensions, but they may agglomerate and flocculate if thesuspension of asphaltene molecules is disturbed through excessstress or incompatibility. This test method provides compat-ibility parameters, which can be used to ass
30、ess stability reserveand compatibility.5.2 A blend is considered stable when the blends peptizingpower is higher than the blends maximum flocculation ratio;3,4both of them can be calculated using empirical blend rules.Refineries and terminal owners can prevent the flocculation ofasphaltenes due to i
31、ncompatibility by assessing the compatibil-ity of fuels beforehand.NOTE 4See Appendix X1 for an example of prediction of compat-ibility.6. Interferences6.1 High content of insoluble inorganic matter (sediment)has some interference in this test method. In this case, theinsoluble matter shall be remov
32、ed by filtration according toTest Method D4870.6.2 The presence of wax, present in paraffinic crudes orfuels from such crudes, does not interfere.3Berryman, T. J., and Lewis, C. P. G., “The Stability of Residual Fuels. Theoryand Practice of the Shell Concept,” 16th CIMAC Conference, Oslo, 1985.4Berg
33、 van den, F. G. A., “Developments in Fuel Oil Blending,” IASH 7thInternational Conference, Graz, Austria, 2000.D7060 12 (2014)27. Apparatus7.1 Integrated Automated Analytical MeasurementSystemThis test method uses an integrated automated ana-lytical measurement system5comprised of a PCbased com-pute
34、r and two titration stations (Fig. 1). See Annex A1 fordetailed information.7.2 The computer controls test sequencing, acquires andaccumulates optical probe signal data, provides processingcalculations, and automatically produces a report of importanttest parameters. The computer is capable of contr
35、olling one ortwo independent titration stations.7.3 Each titration station consists of the following:7.3.1 Automatic titration unit,7.3.2 Heater,7.3.3 Magnetic stirrer,7.3.4 Optical probe, and7.3.5 Reaction cell plus lid.7.4 Magnetic Stirrer/Hotplate, thermostatically controlled.7.5 Stirring Bar, ma
36、gnetic, PFTE-coated, 25 mm in length.8. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society whe
37、resuch specifications are available.6Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.8.2 Asphaltene Solution (3 g/L) Dissolve 0.15 g of dryasphaltenes in 1-methylnaphthalene
38、and dilute to 50 mL. Aprocedure to obtain asphaltenes is described in Appendix X2.Prepare fresh daily, as needed.8.3 Cetane (n-Hexadecane). (WarningIrritating to respi-ratory system and skin.)8.4 Cleaning Solvent, technical grade, 95 % purity, forcleaning. It consists of one of the following:8.4.1 T
39、etrahydrofuran, stabilized. (WarningExtremelyflammable. Irritating to eyes and respiratory system.)5The sole source of supply of the apparatus known to the committee at this timeisAutomated StabilityAnalyser, (User Manual, Version 2), available from Zematra,3194 DG Hoogvliet, The Netherlands. If you
40、 are aware of alternative suppliers,please provide this information to ASTM International Headquarters. Your com-ments will receive careful consideration at a meeting of the responsible technicalcommittee,1which you may attend.6Reagent Chemicals, American Chemical Society Specifications, AmericanChe
41、mical Society, Washington, DC. For Suggestions on the testing of reagents notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Roc
42、kville,MD.FIG. 1 Titration Stations of Integrated Automated Analytical Measurement SystemD7060 12 (2014)38.4.2 Toluene. (WarningFlammable. Health Hazard.)8.4.3 Xylene. (WarningFlammable. Harmful by inhala-tion and in contact with skin. Irritating to skin.)8.5 n-Heptane. (WarningFlammable. Vapor harm
43、ful. Va-por may cause flash fire.)8.6 1-Methylnaphthalene. (WarningHarmful if swal-lowed. Irritating to skin.)8.7 Quality Control (QC) Sample, a stable and homoge-neous residual fuel oil. The QC sample contains at least 1mass % asphaltenes and has approximate viscosities in therange of 180 to 380 mm
44、2/s at 50C.9. Sampling and Test Specimens9.1 Sampling:9.1.1 Obtain samples in accordance with Practices D4057 orD4177.9.1.2 Samples of very viscous materials may be warmeduntil they are reasonably fluid before they are sampled.9.1.3 Store samples prior to taking test specimens at ambi-ent temperatur
45、es.9.2 Test Specimen Preparation:9.2.1 Sample Fuel TemperatureWarm viscous samplesuntil they can be mixed readily before opening the storagecontainer. For fuels with a high wax content (high pour point)the temperature shall be at least 15C above the pour point.9.2.2 Shake or mix the sample thoroughl
46、y. If the samplecontains a high content of insoluble matter, filter the samplethrough a 47-mm diameter glass fiber filter medium (such asWhatman Grade GF/A) using the Test Method D4870 filtrationapparatus.9.2.3 Preparation of Six Specimen BlendsVisually checkthe reaction cell and the lid for cleanli
47、ness. Dissolve specimenin 1-methylnaphthalene in several different ratios of solventaccording to Table 1. Prepare the blends shortly before the testprocedure. Generally follow the sequence: (1) prepare and testBlendsA1 and C1, (2) prepare and test BlendsA2 and C2, and(3) prepare and test Blends B an
48、d D.NOTE 5Blends A1 and B1 can be omitted when the coarse determi-nations are skipped. See also 12.1.1.1.9.2.3.1 Weigh, according to Table 1, specimen to the nearest0.01 g into a clean reaction cell and add a PFTE-coatedmagnetic stirring bar. Place the reaction cell in the center of thepreheated (ap
49、proximately 150C) magnetic stirrer/hotplate andswitch on the magnetic stirrer.Allow the specimen to warm up,until its viscosity is low enough to obtain a smooth stirringperformance.9.2.3.2 Add, according to Table 1, while continuouslystirring, an appropriate volume of 1-methylnaphthalene to thenearest 0.01 mL.9.2.3.3 Put the lid in place. Initiate the test procedure (12.3)within 10 min.NOTE 6Never use excessive force when placing the lid in place.10. Preparation of Apparatus10.1 Prepare the instrument for operation in accordancewith
