1、Designation: D7061 17Standard Test Method forMeasuring n-Heptane Induced Phase Separation ofAsphaltene-Containing Heavy Fuel Oils as SeparabilityNumber by an Optical Scanning Device1This standard is issued under the fixed designation D7061; the number immediately following the designation indicates
2、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. Scope*1.1 This test method covers the quantitative measur
3、ement,either in the laboratory or in the field, of how easily asphaltene-containing heavy fuel oils diluted in toluene phase separateupon addition of heptane. This is measured as a separabilitynumber (%) by the use of an optical scanning device.1.2 The test method is limited to asphaltene-containing
4、heavy fuel oils. ASTM specification fuels that generally fallwithin the scope of this test method are Specification D396,Grade Nos. 4, 5, and 6, Specification D975, Grade No. 4-D,and Specification D2880, Grade Nos. 3-GT and 4-GT. Refineryfractions from which such blended fuels are made also fallwith
5、in the scope of this test method.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user o
6、f this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the
7、 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:2D396 Specification for Fuel OilsD975 Specification for Diesel Fuel OilsD2880
8、 Specification for Gas Turbine Fuel OilsD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of Petroleum andPetroleum Products3. Terminology3.1 Definitions:3.1.1 asphaltenes, n(rarely used in the singular), in petro-leum technology, represent an
9、 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 toluene and the paraffinic solvent is heptane.3.1.2 compatibility, nof crude oils or of heavy fuel oi
10、ls,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 or blended, result in the flocculation orprecipit
11、ation of asphaltenes. Some oils may be compatiblewithin certain 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 that
12、 may or may not settle.3.1.4 peptization, nof asphaltenes in 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 th
13、e asphaltenes.3.1.5.1 DiscussionAn oil with a low stability reserve 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 st
14、ate and not lead toflocculation when blended together.1This 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, Cleanliness and Compatibility of Liquid Fuels.Current editio
15、n approved Dec. 1, 2017. Published March 2018. Originallyapproved in 2004. Last previous edition approved in 2012 as D7061 12. DOI:10.1520/D7061-17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandar
16、ds volume information, refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was dev
17、eloped in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13.1.6 transmittan
18、ce, nof light, the fraction of the incidentlight of a given wavelength that is not reflected or absorbed,but passes through a substance.3.2 Definitions of Terms Specific to This Standard:3.2.1 Heavy Fuel v. 1.03, nthe name of a proprietarycomputer program designed to allow automatic control of testa
19、nd calculations of the results in Test Method D7061.3.2.2 separability number, nin petroleum technology, thestandard deviation of the average transmittance, determined inthis test method, expressed as a percentage figure.3.2.2.1 DiscussionThe separability number estimates thestability reserve of the
20、 oil, where a high separability numberindicates that the oil has a low stability reserve and a lowseparability number that the oil has a high stability reserve.3.2.3 Turbisoft3, nthe name of a proprietary computerspreadsheet program, designed to allow automatic calculationof the results in Test Meth
21、od D7061.4. Summary of Test Method4.1 Dilution of oil with toluene followed by addition ofheptane causes asphaltenes to flocculate, and the oil to phaseseparate. The rate of the phase separation is determined bymeasuring the increase in transmittance in the sample from thebottom of a test tube to th
22、e top (or a portion thereof) over time.The standard deviation of the average transmittance from anumber of scans gives a separability number (%).4.2 The oil is first diluted with toluene in ratios that dependon the oil type (Annex A1). Mix 2 mL of the oil/toluenesolution with 23 mL of heptane. Trans
23、fer 7 mL of the oil/toluene/heptane mixture into a glass vial that is inserted into anoptical scanning device.4.3 The change in light transmittance through the glass vialcontaining the oil/toluene/heptane mixture is recorded byscanning the vial vertically with the optical scanning device.One scan is
24、 run every 60 s for 15 min. An average of thetransmittance is calculated from 1125 readings at 0.04 mmintervals along the glass vial, starting 10 mm above the bottomof the vial and continuing up to 55 mm for each scan. Theseparability number from 16 scans is calculated and reported.5. Significance a
25、nd Use5.1 This procedure describes a rapid and sensitive methodfor estimating the stability reserve of an oil. The stabilityreserve is estimated in terms of a separability number, where alow value of the separability number indicates that there is astability reserve within the oil. When the separabi
26、lity number isbetween 0 to 5, the oil can be considered to have a highstability reserve and asphaltenes are not likely to flocculate. Ifthe separability number is between 5 to 10, the stability reservein the oil will be much lower. However, asphaltenes are, in thiscase, not likely to flocculate as l
27、ong as the oil is not exposed toany worse conditions, such as storing, aging, and heating. If theseparability number is above 10, the stability reserve of the oilis very low and asphaltenes will easily flocculate, or havealready started to flocculate.5.2 This test method can be used by refiners and
28、users ofoils, for which this test method is applicable, to estimate thestability reserves of their oils. Hence, this test method can beused by refineries to control and optimize their refineryprocesses. Consumers of oils can use this test method toestimate the stability reserve of their oils before,
29、 during, andafter storage.5.3 This test method is not intended for predicting whetheroils are compatible before mixing, but can be used fordetermining the separability number of already blended oils.However, oils that show a low separability number are morelikely to be compatible with other oils tha
30、n are oils with highseparability numbers.6. Apparatus6.1 PC-based Computer, into which the software3thatcontrols the apparatus can be loaded. Data is acquired andaccumulated on the hard disk in the computer.6.2 Optical Scanning DeviceThe apparatus,3whichshould be suitably calibrated to the manufactu
31、rersinstructions, consists of a reading head, composed of a pulsedinfrared light source that uses a wavelength of 850 nm. Adetector is situated opposite from the light source and reads thetransmittance through the glass vial containing the specimen.During a scan, the reading head moves up and down a
32、long theglass vial and scans the whole vial going up. The transmittanceis automatically measured every 0.04 mm. During onemeasurement, the time interval between each scan shall be 60 s3The sole source of supply of the optical scanning device (Turbiscan MA2000or Turbiscan Heavy Fuel), and correspondi
33、ng software (Turbisoft or Heavy Fuel v.1.0), known to the committee at this time is available from Formulaction, 10Impasse Borde Basse, 31240 lUnion, France. This device has been foundsatisfactory for the purpose of this test method. If you are aware of alternativesuppliers, please provide this info
34、rmation to ASTM International Headquarters.Your comments will receive careful consideration at a meeting of the responsibletechnical committee,1which you may attend.FIG. 1 Schematic Representation of a Typical Measurement Usingan Optical Scanning DeviceD7061 172and 16 scans shall be run. The measuri
35、ng principle is sche-matically shown in Fig. 1. The measured transmittance alongthe glass vial is reported every 0.04 mm and is automaticallystored on the hard disk in the computer and can be furtherprocessed as described in Section 10 and AnnexA2 and AnnexA3.6.3 Cylindrical Clear Glass Vial with Sc
36、rew Cap, 15 mL,16 mm outside diameter, 12 mm inner diameter, 140 mm high,and of high optical purity shall be used as a sample container.Use once and then discard.6.4 Pipette, Graduated or Automatic, 5 mL and 10 mL.6.5 Graduated Cylinder, 25 mL.6.6 Clear Glass Bottle with Cap, 250 mL.6.7 Clear Glass
37、Bottle with Cap, 50 mL.6.8 Magnetic Bar, TFE-fluorocarbon-coated.6.9 Magnetic Stirrer.6.10 Balance, precision 60.01 g.6.11 Stopwatch, capable of 0.1 s.6.12 Burette, 25 mL, Grade A.6.13 Oven, capable of 60 C at 60.1 C.7. Reagents and Materials7.1 Purity of ReagentsReagents of technical grade (99 %pur
38、ity) and higher are adequate for this test.7.2 Heptane. (WarningFlammable. Vapor harmful. Va-por may cause flash fire.)7.3 Toluene. (WarningFlammable. Vapor harmful. Vapormay cause flash fire.)8. Sampling and Test Specimens8.1 The oil sample drawn for the purpose of this test methodshall be represen
39、tative of the lot of oil. Obtain the sample inaccordance with the procedures of Practice D4057 or D4177,ifpossible.8.2 When working with the oil sample in the laboratory, theoil shall be stirred either manually or mechanically until themixture is homogenous and representative for the wholesample bef
40、ore withdrawing oil for testing.8.3 When working with solid or highly viscous oils, the oilmay be heated (for example, on a heating plate, in an oven, or,if a drum is heated, by an electrical heating belt or steam shed)to obtain a lower viscosity prior to weighing and mixing. It isthen important tha
41、t the whole sample is fluid to ensure ahomogenous mixture and that the sample withdrawn is repre-sentative of the whole sample.9. Procedure9.1 Prepare the instrument for measuring by turning it on atleast 1 h before use, and make preparation so that one scan canbe run automatically every 60 s for 15
42、 min. For more detailedinstructions, see Annex A2 and Annex A3.9.2 Sample to be placed in an oven at 60 C for 24 h toensure homogeneity.9.3 Remove the sample from the oven and shake for 1 minto ensure mixing.9.4 With the aim to increase and achieve a comparabletransmittance for all types of oils, we
43、igh in 5 g 6 0.01 g of theoil sample on a balance. Record the weight of oil added to fourdecimal places and dilute with toluene, in a weight ratio from1:3 to 1:20 to have a baseline under 15 % of transmittance, forguidance see Annex A1, in a bottle with cap (6.6). Carefullyadd a magnetic bar to the
44、oil-toluene solution ensuring none ofthe oil/toluene mixture is lost, and seal the bottle. Shake the jarwell until the oil/toluene mixture no longer adheres to thebottom of the jar. Put the bottle on a magnetic stirrer and stirthe mixture for 90 min 6 5 min.9.5 Using a 25 mL burette (6.12), add 23 m
45、L of n-heptaneinto a glass bottle (6.7). Use a pipette to add 2.0 mL of theoil/toluene mixture prepared in 9.4 to the heptane and shake themixture briskly for 6 s.9.6 Use a pipette to transfer 7 mL of the oil-toluene-heptanemixture in a period of less than 10 s into the cylindrical clearglass vial a
46、nd screw the cap on (6.3), taking care not to depositmaterial on the tube walls. If 10 s is exceeded, the rest shouldbe stopped and the sample retested.9.7 Immediately place the cylindrical glass vial, with cap, inthe instrument at ambient temperature (20 C to 25 C) andstart to measure at once.NOTE
47、1The transmittance through the cylindrical glass vial is nowrecorded every 60 s for 15 min and stored by the software on the hard diskof the computer.9.8 When the measurement is finished, remove the glassvial from the optical scanning device and clean the glass vialwith toluene in a fume hood.10. Ca
48、lculation and Interpretation of Results10.1 Calculation of Results:10.1.1 The following calculations may be completed eithermanually, by using a spreadsheet program (described in AnnexA2) or automatically, using the software Heavy Fuel v. 1.0(described in Annex A3).10.1.2 Analyze the transmittance b
49、etween 10 mm to 55 mm(10 mm from the bottom of the glass vial), that is, calculate theaverage transmittance (Xi) recorded in this region for eachminute.10.1.3 Calculate the total average transmittance (XT) of eachof the 16 scans.10.1.4 Calculate the separability number using the equationfor standard deviation:Separability number 5!(i51nXi2 XT!2n 2 1(1)where:Xi= average transmittance for each 60 s,XT= average of XiSXT5X11X21X1616,DandD7061 173n = the set of replicate measurements (16 in the method).10.2 Interpretation of Results:10.2.1 The separability nu
