1、Designation: D7060 09D7060 12Standard 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 indicates the
2、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. Scope*1.1 This test method covers a procedure for quantifying
3、 the maximum flocculation ratio of the asphaltenes in the oil and thepeptizing power of the oil medium, by an automatic instrument using an optical device.1.2 This test method is applicable to atmospheric or vacuum distillation residues, thermally cracked residue, intermediate andfinished residual f
4、uel oils, containing at least 1 mass % asphaltenes. This test method has not been developed for asphalts.NOTE 1An optical probe detects the formation of flocculated asphaltenes. The start of flocculation is interpreted when a significant and sustainedincrease in rate-of-change of signal, as measured
5、 by the optical probe, ensures flocculation is in progress. The start of flocculation can be detectedunambiguously when the sample contains at least 1 % mass asphaltenes as measured by Test Method D6560.NOTE 2This test method is applicable to products typical of Specification D396Grades 5L, 5H, and
6、6, and Specification D2880Grades 3-GT and4-GT.1.3 This test method was evaluated in an interlaboratory study in the nominal range of 32 to 76 for the maximum flocculationratio and in the nominal range of 36 to 95 for peptizing power.NOTE 3The nominal range is determined by (min. sample meanReproduci
7、bility) to (max. sample mean + Reproducibility).1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsib
8、ilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D396 Specification for Fuel OilsD2880 Specification for Gas Turbine Fuel OilsD4057 Practice for Manu
9、al Sampling of Petroleum and Petroleum ProductsD4177 Practice for Automatic Sampling of Petroleum and Petroleum ProductsD4870 Test Method for Determination of Total Sediment in Residual FuelsD6300 Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products an
10、d LubricantsD6560 Test Method for Determination of Asphaltenes (Heptane Insolubles) in Crude Petroleum and Petroleum ProductsD6792 Practice for Quality System in Petroleum Products and Lubricants Testing Laboratories3. Terminology3.1 Definitions:3.1.1 asphaltene,asphaltenes, n(rarely used in the sin
11、gular), in petroleum technology, a molecule of high molecular mass, highcarbon/hydrogen ratio, and containing heteroatoms.represent an oil fraction that is soluble in a specified aromatic solvent butseparates upon addition of an excess of a specified paraffinic solvent.1 This test method is under th
12、e jurisdiction of ASTM Committee D02 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.14 onStability and Cleanliness of Liquid Fuels.Current edition approved June 1, 2009Nov. 1, 2012. Published July 2009March 2013. Originally approved in 2004. Last previous e
13、dition approved in 20052009 asD706005.09. DOI: 10.1520/D7060-09.10.1520/D7060-12.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page
14、on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that use
15、rs consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Consho
16、hocken, PA 19428-2959. United States13.1.1.1 DiscussionAsphaltenes are found largely in crude oils and in heavy fuel oils containing residual fractions. They are insoluble in alkanes suchas In this test method, the n-heptane and cetane, but soluble in aromatic solvents such as benzene, toluene, and1
17、-methylnaphthalene.aromatic solvent is 1-methylnapthalene, and the paraffinic solvent is n-hexadecane.3.1.2 compatibility, n of crude oils or of heavy fuel oils, the ability of two or more crude oils or fuel oils to blend togetherwithin certain concentration ranges without evidence of separation, su
18、ch as the formation of multiple phases.3.1.2.1 DiscussionIncompatible heavy fuel oils or crude oils, when mixed or blended, result in the flocculation or precipitation of asphaltenes. Someoils may be compatible within certain concentration ranges in specific mixtures, but incompatible outside those
19、ranges.3.1.3 flocculation, n of asphaltenes from crude oils or heavy fuel oils, the aggregation of colloidally dispersed asphaltenes intovisibly larger masses which may or may not settle.3.1.4 peptization, n of asphaltenes in crude oils or heavy fuel oils, the dispersion of asphaltenes to produce a
20、colloidaldispersion.3.1.5 stability reserve, n in petroleum technology, the property of an oil to maintain asphaltenes in a peptized state and preventflocculation of the asphaltenes.3.1.5.1 DiscussionAn oil with a low stability reserve is likely to undergo flocculation of asphaltenes when stressed (
21、for example, extended heatedstorage) or blended with a range of other oils. Two oils each with a high stability reserve are likely to maintain asphaltenes in apeptized state and not lead to flocculation when blended together.3.2 Definitions of Terms Specific to This Standard:3.2.1 critical cetane di
22、lution, nnumber of millilitres of cetane with which 1 g of undiluted sample can be diluted until it justdoes not flocculate the asphaltenes.3.2.2 critical dilution, nnumber of millilitres of 1-methylnaphthalene and cetane with which 1 g of undiluted sample can bediluted until it just does not floccu
23、late the asphaltenes.3.2.2.1 DiscussionThe number of millilitres of 1-methylnaphthalene and cetane is variable and depends on the ratio of sample to 1-methylnaphthaleneat the starting point and the sample type.3.2.3 flocculation ratio, npercentage by volume of 1-methylnaphtalene in a mixture of 1-me
24、thylnaphthalene and cetane.3.2.4 flocculation ratio at critical dilution, npercentage by 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 with cetane, where flocculation of asphaltenes is not d
25、etected by theoptical probe as a significant and sustained increase in rate-of-change of signal.3.2.6 maximum flocculation ratio, nof asphaltenes, minimum required solvency power, expressed as percentage by volumeof 1-methylnaphthalene in a mixture of 1-methylnaphthalene and cetane, to keep the asph
26、altenes in a colloidal solution.3.2.6.1 DiscussionMaximum flocculation ratio is the flocculation ratio at extrapolated infinite dilution of the sample.3.2.7 oil medium, nthat portion of a sample of heavy fuel oil or crude oil that surrounds and colloidally disperses theasphaltenes.3.2.7.1 Discussion
27、For purposes of this test method, an oil sample is considered to be composed of an oil medium (sometimes called an oil matrixor maltenes) and asphaltenes.3.2.8 peptizing power, navailable solvency power, expressed as percentage by volume of 1-methylnaphthalene in a mixtureof 1-methylnaphthalene and
28、cetane, to keep asphaltenes in a colloidal solution.D7060 1223.2.9 reciprocal dilution, ndilution ratio of sample in solvent mixture of 1-methylnaphthalene and cetane.3.3 Symbols:FRmax = maximum flocculation ratioFRx = flocculation ratio at critical dilutionPo = peptizing powerXmin = critical cetane
29、 dilutionXc = critical dilution4. Summary of Test Method4.1 Six portions of the sample are diluted in various ratios with 1-methylnaphthalene. Each solution is inserted into theautomatic apparatus, and titrated with cetane until flocculation of asphaltenes is detected by the optical probe. The first
30、 twosolutions are titrated with cetane in coarse determinations in which the flocculation ratio is decreased in 5 % steps. The coarsedeterminations help to establish suitable starting values for the fine determinations, in which the flocculation ratio is decreased in1 % steps. The four flocculation
31、ratios at critical dilution, measured during the fine determinations, are used to calculate themaximum flocculation ratio of the samples asphaltenes and the peptizing power of the samples oil medium.5. Significance and Use5.1 Asphaltenes are naturally occurring materials in crude petroleum and petro
32、leum products containing residual material. Theasphaltenes are usually present in colloidal suspensions, but they may agglomerate and flocculate if the suspension of asphaltenemolecules is disturbed through excess stress or incompatibility. This test method provides compatibility parameters, which c
33、an beused to assess stability reserve and compatibility.5.2 Ablend is considered stable when the blends peptizing power is higher than the blends maximum flocculation ratio;3,4 bothof them can be calculated using empirical blend rules. Refineries and terminal owners can prevent the flocculation of a
34、sphaltenesdue to incompatibility by assessing the compatibility of fuels beforehand.NOTE 4See Appendix X1 for an example of prediction of compatibility.6. Interferences6.1 High content of insoluble inorganic matter (sediment) has some interference in this test method. In this case, the insolublematt
35、er shall be removed by filtration according to Test Method D4870.6.2 The presence of wax, present in paraffinic crudes or fuels from such crudes, does not interfere.7. Apparatus7.1 Integrated Automated Analytical Measurement SystemThis test method uses an integrated automated analyticalmeasurement s
36、ystem5 comprised of a PCbased computer and two titration stations (Fig. 1). See Annex A1 for detailedinformation.7.2 The computer controls test sequencing, acquires and accumulates optical probe signal data, provides processingcalculations, and automatically produces a report of important test param
37、eters. The computer is capable of controlling one or twoindependent 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, thermosta
38、tically controlled.7.5 Stirring Bar, magnetic, PFTE-coated, 25 mm in length.8. Reagents and Materials8.1 Purity of ReagentsReagent grade chemicals shall be used in all tests. Unless otherwise indicated, it is intended that allreagents conform to the specifications of the Committee on Analytical Reag
39、ents of the American Chemical Society where such3 Berryman, T. J., and Lewis, C. P. G., “The Stability of Residual Fuels. Theory and Practice of the Shell Concept,” 16th CIMAC Conference, Oslo, 1985.4 Berg van den, F. G. A., “Developments in Fuel Oil Blending,” IASH 7th International Conference, Gra
40、z, Austria, 2000.5 The sole source of supply of the apparatus known to the committee at this time isAutomated StabilityAnalyser, (User Manual, Version 2), available from Zematra, 3194DG Hoogvliet, The Netherlands. If you are aware of alternative suppliers, please provide this information to ASTM Int
41、ernational Headquarters. Your comments will receivecareful consideration at a meeting of the responsible technical committee,1 which you may attend.D7060 123specifications are available.6 Other grades may be used, provided it is first ascertained that the reagent is of sufficiently high purityto per
42、mit its use without lessening the accuracy of the determination.8.2 Asphaltene Solution (3 g/L) Dissolve 0.15 g of dry asphaltenes in 1-methylnaphthalene and dilute to 50 mL.Aprocedureto obtain asphaltenes is described in Appendix X2. Prepare fresh daily, as needed.8.3 Cetane (n-Hexadecane). (Warnin
43、gIrritating to respiratory system and skin.)8.4 Cleaning Solvent, technical grade, 95 % purity, for cleaning. It consists of one of the following:8.4.1 Tetrahydrofuran, stabilized. (WarningExtremely flammable. Irritating to eyes and respiratory system.)8.4.2 Toluene. (WarningFlammable. Health Hazard
44、.)8.4.3 Xylene. (WarningFlammable. Harmful by inhalation and in contact with skin. Irritating to skin.)8.5 n-Heptane. (WarningFlammable. Vapor harmful. Vapor may cause flash fire.)8.6 1-Methylnaphthalene. (WarningHarmful if swallowed. Irritating to skin.)8.7 Quality Control (QC) Sample, a stable and
45、 homogeneous residual fuel oil. The QC sample contains at least 1 mass %asphaltenes and has approximate viscosities in the range of 180 to 380 mm2/s at 50C.9. Sampling and Test Specimens9.1 Sampling:9.1.1 Obtain samples in accordance with Practices D4057 or D4177.9.1.2 Samples of very viscous materi
46、als may be warmed until they are reasonably fluid before they are sampled.9.1.3 Store samples prior to taking test specimens at ambient temperatures.9.2 Test Specimen Preparation:6 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For Suggestions
47、 on the testing of reagents not listed bythe American Chemical Society, see Annual Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.FIG. 1 Titration Stations of Integ
48、rated Automated Analytical Measurement SystemD7060 1249.2.1 Sample Fuel TemperatureWarm viscous samples until they can be mixed readily before opening the storage container.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 m
49、ix the sample thoroughly. If the sample contains a high content of insoluble matter, filter the sample througha 47-mm diameter glass fiber filter medium (such as Whatman Grade GF/A) using the Test Method D4870 filtration apparatus.9.2.3 Preparation of Six Specimen BlendsVisually check the reaction cell and the lid for cleanliness. Dissolve specimen in1-methylnaphthalene in several different ratios of solvent according to Table 1. Prepare the blends shortly before the test procedure.Generally follow the sequence: (1) prepare and test
