ASTM D7061-2012 red 3125 Standard Test Method for Measuring n-Heptane Induced Phase Separation of Asphaltene-Containing Heavy Fuel Oils as Separability Number by an Optical Scannin.pdf

1、Designation: D7061 06D7061 12Standard 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 in

2、dicates 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 quantitativ

3、e measurement, either in the laboratory or in the field, of how easilyasphaltene-containing heavy fuel oils diluted in toluene phase separate upon 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-c

4、ontaining heavy fuel oils. ASTM specification fuels that generally fall within thescope of this test method are Specification D396, Grade Nos. 4, 5, and 6, Specification D975, Grade No. 4-D, and SpecificationD2880, Grade Nos. 3-GT and 4-GT. Refinery fractions from which such blended fuels are made a

5、lso fall within the scope of thistest method.1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibili

6、tyof 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 OilsD975 Specification for Diesel Fuel OilsD2880 Specification for Gas Turb

7、ine Fuel OilsD4057 Practice for Manual Sampling of Petroleum and Petroleum ProductsD4177 Practice for Automatic Sampling of Petroleum and Petroleum Products3. Terminology3.1 Definitions:3.1.1 asphaltene,asphaltenes, n(rarely used in the singular), in petroleum technology, a molecule of high molecula

8、r 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.3.1.1.1 DiscussionAsphaltenes are found largely in crude oils and in heavy fuel oils conta

9、ining 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-methylnaphthalene. aromatic solvent is toluene and the paraffinic solvent is heptane.3.1.2 compatibility, nof crude oils or

10、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, such as the formation of multiple phases.1 This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products and Lubricants

11、 and is the direct responsibility of Subcommittee D02.14 onStability and Cleanliness of Liquid Fuels.Current edition approved May 1, 2006Nov. 1, 2012. Published June 2006March 2013. Originally approved in 2004. Last previous edition approved in 20052006 asD706105a.06. DOI: 10.1520/D7061-06. 10.1520/

12、D7061-12.2 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 on the ASTM website.This document is not an ASTM standard and is intende

13、d 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 users consult prior editions as appropriate. In all cases only the current

14、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 Conshohocken, PA 19428-2959. United States13.1.2.1 DiscussionIncompatible heav

15、y 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 ranges.3.1.3 flocculation, nof asphaltenes from crude oils or heavy fuel o

16、ils, the aggregation of colloidally dispersed asphaltenes intovisibly larger masses that 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 colloidaldispersion.3.1.5 stability reserve, nin petroleum technology, the p

17、roperty 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 (for example, extended heatedstorage) or blended with a range of other oils. T

18、wo oils each with a high stability reserve are likely to maintain asphaltenes in apeptized state and not lead to flocculation when blended together.3.1.6 transmittance, nof light, the fraction of the incident light of a given wavelength that is not reflected or absorbed, butpasses through a substanc

19、e.3.2 Definitions of Terms Specific to This Standard:3.2.1 Heavy Fuel v. 1.03, nthe name of a proprietary computer program designed to allow automatic control of test andcalculations of the results in Test Method D7061.3.2.2 separability number, nin petroleum technology, the standard deviation of th

20、e average transmittance, determined in thistest method, expressed as a percentage figure.3.2.2.1 DiscussionThe separability number estimates the stability reserve of the oil, where a high separability number indicates that the oil has a lowstability reserve and a low separability number that the oil

21、 has a high stability reserve.3.2.3 Turbisoft3, nthe name of a proprietary computer spreadsheet program, designed to allow automatic calculation of theresults in Test Method D7061.4. Summary of Test Method4.1 Dilution of oil with toluene followed by addition of heptane causes asphaltenes to floccula

22、te, and the oil to phase separate.The rate of the phase separation is determined by measuring the increase in transmittance in the sample from the bottom of a testtube to the top (or a portion thereof) over time. The standard deviation of the average transmittance from a number of scans givesa separ

23、ability number (%).4.2 The oil is first diluted with toluene in ratios that depend on the oil type (Annex A1). Mix 2 mL of the oil/toluene solutionwith 23 mL of heptane. Transfer 7 mL of the oil/toluene/heptane mixture into a glass vial that is inserted into an optical scanningdevice.4.3 The change

24、in light transmittance through the glass vial containing the oil/toluene/heptane mixture is recorded by scanningthe vial vertically with the optical scanning device. One scan is run every 60 s for 15 min. An average of the transmittance iscalculated from 1125 readings at 0.04-mm intervals along the

25、glass vial, starting 10 mm above the bottom of the vial andcontinuing up to 55 mm for each scan. The separability number from 16 scans is calculated and reported.5. Significance and Use5.1 This procedure describes a rapid and sensitive method for estimating the stability reserve of an oil. The stabi

26、lity reserve isestimated in terms of a separability number, where a low value of the separability number indicates that there is a stability reservewithin the oil. When the separability number is between 0 to 5, the oil can be considered to have a high stability reserve andasphaltenes are not likely

27、 to flocculate. If the separability number is between 5 to 10, the stability reserve in the oil will be muchlower. However, asphaltenes are, in this case, not likely to flocculate as long as the oil is not exposed to any worse conditions, such3 The sole source of supply of the optical scanning devic

28、e (Turbiscan MA2000 or Turbiscan Heavy Fuel), and corresponding software (Turbisoft or Heavy Fuel v. 1.0),known to the committee at this time is available from Formulaction, 10 Impasse Borde Basse, 31240 lUnion, France. This device has been found satisfactory for the purposeof this test method. If y

29、ou are aware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive carefulconsideration at a meeting of the responsible technical committee,1 which you may attend.D7061 122as storing, aging, and heating. If the separability number is

30、 above 10, the stability reserve of the oil is very low and asphalteneswill easily flocculate, or have already started to flocculate.5.2 This test method can be used by refiners and users of oils, for which this test method is applicable, to estimate the stabilityreserves of their oils. Hence, this

31、test method can be used by refineries to control and optimize their refinery processes. Consumersof oils can use this test method to estimate the stability reserve of their oils before, during, and after storage.5.3 This test method is not intended for predicting whether oils are compatible before m

32、ixing, but can be used for determiningthe separability number of already blended oils. However, oils that show a low separability number are more likely to becompatible with other oils than are oils with high separability numbers.6. Apparatus6.1 PC-based Computer, into which the software3 that contr

33、ols the apparatus can be loaded. Data is acquired and accumulatedon the hard disk in the computer.6.2 Optical Scanning DeviceThe apparatus,3 which should be suitably calibrated to the manufacturers instructions, consistsof a reading head, composed of a pulsed infrared light source that uses a wavele

34、ngth of 850 nm. A detector is situated oppositefrom the light source and reads the transmittance through the glass vial containing the specimen. During a scan, the reading headmoves up and down along the glass vial and scans the whole vial going up. The transmittance is automatically measured every0

35、.04 mm. During one measurement, the time interval between each scan shall be 60 s and 16 scans shall be run. The measuringprinciple is schematically shown in Fig. 1. The measured transmittance along the glass vial is reported every 0.04 mm and isautomatically stored on the hard disk in the computer

36、and can be further processed as described in Section 10 and Annex A2 andAnnex A3.6.3 Cylindrical Clear Glass Vial with Screw Cap, 15 mL, 16 mm outside diameter, 12 mm inner diameter, and 140 mm high,and of high optical purity shall be used as a sample container. Use once and then discard.6.4 Pipette

37、, Graduated or Automatic, 5 and 10 mL.6.5 Graduated Cylinder, 25 mL.6.6 Clear Glass Bottle with Cap, 250 mL.6.7 Clear Glass 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, Grad

38、e A.FIG. 1 Schematic Representation of a Typical Measurement Using an Optical Scanning DeviceD7061 1236.13 Oven, capable of 60C at 60.1C.7. Reagents and Materials7.1 Purity of ReagentsReagents of technical grade (95 %(99 % purity) and higher are adequate for this test.7.2 Heptane. (WarningFlammable.

39、 Vapor harmful. Vapor may cause flash fire.)7.3 Toluene. (WarningFlammable. Vapor harmful. Vapor may cause flash fire.)8. Sampling and Test Specimens8.1 The oil sample drawn for the purpose of this test method shall be representative of the lot of oil. Obtain the sample inaccordance with the procedu

40、res of Practice D4057 or D4177, if possible.8.2 When working with the oil sample in the laboratory, the oil shall be stirred either manually or mechanically until the mixtureis homogenous and representative for the whole sample before withdrawing oil for testing.8.3 When working with solid or highly

41、 viscous oils, the oil may be heated (for example, on a heating plate, in an oven, or, ifa drum is heated, by an electrical heating belt or steam shed) to obtain a lower viscosity prior to weighing and mixing. It is thenimportant that the whole sample is fluid to ensure a homogenous mixture and that

42、 the sample withdrawn is representative of thewhole sample.9. Procedure9.1 Prepare the instrument for measuring by turning it on at least 1 h before use, and make preparation so that one scan canbe run automatically every 60 s for 15 min. For more detailed instructions, see Annex A2 and Annex A3.9.2

43、 Sample to be placed in an oven at 60C for 24 h to ensure homogeneity.9.3 Remove the sample from the oven and shake for 1 min to ensure mixing.9.4 With the aim to increase and achieve a comparable transmittance for all types of oils, weigh in 15 5 6 0.01 g of the oilsample on a balance balance. Reco

44、rd the weight of oil added to four decimal places and dilute with toluene, in a weight ratio inaccordance with from 1:3 to 1:20 to have a baseline under 15% of transmittance, for guidance see Annex A1, in a bottle with cap(6.6), and shake the bottle well. Add ). Carefully add a magnetic bar to the o

45、il-toluene solution. solution ensuring none of theoil/toluene mixture is lost, and seal the bottle. Shake the jar well until the oil/toluene mixture no longer adheres to the bottom ofthe jar. Put the bottle on a magnetic stirrer and stir the mixture for a minimum of 1 h but not more than 3 h.90 6 5

46、min.9.2 Prepare the instrument for measuring by turning it on and make preparations so that one scan can be run automatically every60 s for 15 min. For more detailed instructions, see Annex A2 and Annex A3.9.5 Using a graduated cylinder, transfer 25 mL burette (6.12), add 23 mL of n-heptane into a g

47、lass bottle (6.7). Use a pipetteto add 22.0 mL of the oil/toluene mixture prepared in 9.19.4 to the heptane and shake the mixture briskly for 6 s.9.6 Use a pipette to transfer 7 mLof the oil-toluene-heptane mixture immediately in a period of less than 10 s into the cylindricalclear glass vial and sc

48、rew the cap on (6.3).), taking care not to deposit material 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, in the instrument at ambient temperature (20 to 25C) and start tomeasure at once.NOTE 1The

49、 transmittance through the cylindrical glass vial is now recorded every 60 s for 15 min and stored by the software on the hard disk ofthe computer.9.8 When the measurement is finished, remove the glass vial from the optical scanning device and clean the glass vial withtoluene in a fume hood.10. Calculation and Interpretation of Results10.1 Calculation of Results:10.1.1 The following calculations may be completed either manually, by using a spreadsheet program (described in Annex A2)or automatically, using the software Heavy Fuel v. 1.0 (described in Annex