1、Designation: D 7060 09Standard 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 D 7060; the number immediately following the designation indicates the year o
2、foriginal 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. Scope*1.1 This test method covers a procedure for quantifying thema
3、ximum 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 residual fuel oils,
4、 containing at least 1 mass %asphaltenes. This test method has not been developed forasphalts.NOTE 1An optical probe detects the formation of flocculated asphalt-enes. The start of flocculation is interpreted when a significant andsustained increase in rate-of-change of signal, as measured by the op
5、ticalprobe, 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 D 6560.NOTE 2This test method is applicable to products typical of Specifi-cation D 396Grades 5L, 5H, and 6, and Sp
6、ecification D 2880Grades3-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 meanReproducibility) to
7、 (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 theresponsibility of the u
8、ser 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:2D 396 Specification for Fuel OilsD 2880 Specification for Gas Turbine Fuel OilsD 4057 Practice for Manual Samp
9、ling of Petroleum andPetroleum ProductsD 4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD 4870 Test Method for Determination of Total Sediment inResidual FuelsD 6300 Practice for Determination of Precision and BiasData for Use in Test Methods for Petroleum Products andLubrica
10、ntsD 6560 Test Method for Determination of Asphaltenes(Heptane Insolubles) in Crude Petroleum and PetroleumProductsD 6792 Practice for Quality System in Petroleum Productsand Lubricants Testing Laboratories3. Terminology3.1 Definitions:3.1.1 asphaltene, nin petroleum technology, a moleculeof high mo
11、lecular mass, high carbon/hydrogen ratio, andcontaining heteroatoms.3.1.1.1 DiscussionAsphaltenes are found largely in crudeoils and in heavy fuel oils containing residual fractions. Theyare insoluble in alkanes such as n-heptane and cetane, butsoluble in aromatic solvents such as benzene, toluene,
12、and1-methylnaphthalene.3.1.2 compatibility, nof 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 o
13、ils or crudeoils, when mixed or blended, result in the flocculation or1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.14 on Stability and Cleanliness of Liquid Fuels.Current edition approved Jun
14、e 1, 2009. Published July 2009. Originally approvedin 2004. Last previous edition approved in 2005 as D 706005.2For 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 s
15、tandards Document Summary page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.precipitation of asphaltenes. Some oils may be compatiblewithin certa
16、in concentration ranges in specific mixtures, butincompatible outside those ranges.3.1.3 flocculation, nof 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, nof asphaltenes in
17、crude oils or heavyfuel oils, the dispersion of asphaltenes to produce a colloidaldispersion.3.1.5 stability reserve, nin 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 r
18、eserve islikely to undergo flocculation of asphaltenes 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 Def
19、initions of Terms Specific to This Standard:3.2.1 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 which1gofun
20、dilutedsample can be diluted until it just does not 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, npercenta
21、ge by volume of1-methylnaphtalene in a mixture of 1-methylnaphthalene andcetane.3.2.4 flocculation ratio at critical dilution, npercentageby volume of 1-methylnaphthalene in a mixture of1-methylnaphthalene and cetane at the inflection point.3.2.5 inflection point, nlast step during the titration wit
22、hcetane, where flocculation of asphaltenes is not 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
23、 of1-methylnaphthalene and cetane, to keep the asphaltenes 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 collo
24、idally disperses theasphaltenes.3.2.7.1 DiscussionFor 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-methyln
25、aphthalene in amixture of 1-methylnaphthalene and cetane, to keep asphalt-enes 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
26、= peptizing powerXmin = critical cetane dilutionXc = 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 det
27、ected by the optical probe. The first twosolutions 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 i
28、n 1 % steps. The four flocculation ratios at criticaldilution, 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 materi
29、als in crudepetroleum and petroleum products containing residual mate-rial. The asphaltenes are usually present in colloidal suspen-sions, but they may agglomerate and flocculate if the suspen-sion of asphaltene molecules is disturbed through excess stressor incompatibility. This test method provide
30、s compatibilityparameters, which can be used to assess stability reserve andcompatibility.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
31、can prevent the flocculation ofasphaltenes due to incompatibility 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 metho
32、d. In this case, theinsoluble matter shall be removed by filtration according toTest Method D 4870.6.2 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 She
33、ll Concept,” 16th CIMAC Conference, Oslo, 1985.4Berg van den, F. G. A., “Developments in Fuel Oil Blending,” IASH 7thInternational Conference, Graz, Austria, 2000.D70600927. Apparatus7.1 Integrated Automated Analytical MeasurementSystemThis test method uses an integrated automated ana-lytical measur
34、ement system5comprised of a PCbased com-puter 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
35、parameters. The computer is capable of controlling 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, ther
36、mostatically controlled.7.5 Stirring Bar, magnetic, 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 R
37、eagents of the American Chemical Society wheresuch 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
38、g of dryasphaltenes in 1-methylnaphthalene 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. I
39、t consists of one of the following:8.4.1 Tetrahydrofuran, stabilized. (WarningExtremelyflammable. Irritating to eyes and respiratory system.)5The sole source of supply of the apparatus known to the committee at this timeis Automated Stability Analyser, (User Manual, Version 2), available from Zematr
40、a,3194 DG Hoogvliet, The Netherlands. If you 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
41、Chemical Society Specifications, AmericanChemical 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
42、. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.FIG. 1 Titration Stations of Integrated Automated Analytical Measurement SystemD70600938.4.2 Toluene.(WarningFlammable. Health Hazard.)8.4.3 Xylene.(WarningFlammable. Harmful by inhala-tion and in contact with skin. Irritating to skin.)8.5 n-Hept
43、ane.(WarningFlammable. Vapor harmful. 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 viscosit
44、ies in therange of 180 to 380 mm2/s at 50C.9. Sampling and Test Specimens9.1 Sampling:9.1.1 Obtain samples in accordance with Practices D 4057or D 4177.9.1.2 Samples of very viscous materials may be warmeduntil they are reasonably fluid before they are sampled.9.1.3 Store samples prior to taking tes
45、t specimens at ambi-ent temperatures.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
46、 Shake or mix the sample thoroughly. 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 D 4870 filtra-tion apparatus.9.2.3 Preparation of Six Specimen BlendsVisually checkthe
47、reaction cell and the lid for cleanliness. 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 testBlends A1 and C1, (2) prepare and test Blends A2 and
48、C2, and(3) prepare and test Blends B and 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
49、 cell in the center of thepreheated (approximately 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 instrum
