1、Designation: D7689 17Standard Test Method forCloud Point of Petroleum Products and Liquid Fuels (MiniMethod)1This standard is issued under the fixed designation D7689; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of las
2、t 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 determination of the cloudpoint of petroleum products, biodiesel, and biodiesel blendsthat a
3、re transparent in layers 40 mm in thickness, using anautomatic instrument.1.2 This test method covers the range of cloud pointtemperatures from 50 C to +6 C.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 d
4、oes not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility 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.1.5 This international standard wa
5、s developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenc
6、ed Documents2.1 ASTM Standards:2D2500 Test Method for Cloud Point of Petroleum Productsand Liquid FuelsD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD6708 Practice for Statistical Assessment and Improvemen
7、tof Expected Agreement Between Two Test Methods thatPurport to Measure the Same Property of a Material2.2 Energy Institute Standard:3IP219 Test Method for Cloud Point of Petroleum Products3. Terminology3.1 Definitions:3.1.1 biodiesel, nfuel comprising mono-alkyl esters oflong-chain fatty acids deriv
8、ed from vegetable oils or animalfats, designated B100.3.1.1.1 DiscussionBiodiesel is typically produced by areaction of vegetable oil or animal fat with an alcohol such asmethanol or ethanol in the presence of a catalyst to yieldmono-esters and glycerin. The fuel typically may contain up to14 differ
9、ent types of fatty acids that are chemically transformedinto fatty acid methyl esters (FAME).3.1.2 biodiesel blend (BXX), nblend of biodiesel fuel withpetroleum-based diesel fuel designated BXX, where XX is thevolume percentage (as a whole number without the percentagesign) of biodiesel.3.1.3 cloud
10、point, nin petroleum products and biodieselfuels, the temperature of a liquid specimen when the smallestobservable cluster of wax crystals first occurs upon coolingunder prescribed conditions.3.1.3.1 DiscussionThe cloud point occurs when the tem-perature of the specimen is low enough to cause wax cr
11、ystalsto precipitate. In a homogeneous liquid, the cloud is alwaysnoted first at the location in the specimen where the specimentemperature is the lowest. The cloud point is the temperature atwhich the crystals first occur, regardless of their location in thespecimen, and not after extensive crystal
12、lization has takenplace. The wax crystals that precipitate at lower temperaturesare typically, but not excluded to, straight-chain hydrocarbonsand lipids.3.2 Definitions of Terms Specific to This Standard:3.2.1 D2500/IP219 equivalent cloud point, ntemperatureof a specimen, in integers, calculated by
13、 applying a bias androunding the results of this test method to the next lowerinteger (see 12.2).1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.07 on Flow Properties.Current edit
14、ion approved May 1, 2017. Published May 2017. Originallyapproved in 2011. Last previous edition approved in 2011 as D7689 11.DOI:10.1520 D7689-17.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards
15、 volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Energy Institute, 61 New Cavendish St., London, WIG 7AR,U.K., http:/www.energyinst.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor D
16、rive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations
17、issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1Mon Apr 30 54 3.2.1.1 DiscussionThis test method produces results with0.1 C resolution. Should the user wish to provide results witha similar format to Test Method D2500, then this calculationcan be performed. Some a
18、pparatus can perform this calculationautomatically.3.2.2 mini method, nin cloud point test methods, auto-matic test procedure using a small sample size, prescribedcooling rate, specimen receptacle, and optical system fordetection of crystal formation.3.2.2.1 DiscussionThe prescribed cooling rate is
19、de-scribed in 4.1, the specimen receptacle is described in 7.1, andthe optical system for detection of crystal formation is de-scribed in 4.1.4. Summary of Test Method4.1 After inserting the test specimen into the automaticapparatus, and initiation of the program, the test specimen isheated, if nece
20、ssary, to a starting temperature and then cooledby prescribed rates (11.5 and 11.6). The test specimen iscontinuously monitored for appearance of hydrocarbon crystalswith opposing light emitter and optical receiver (Annex A1).When the crystallization in the specimen is detected by theoptical system,
21、 the temperature is recorded to within 0.1 Cresolution. The specimen is then heated to facilitate the start ofthe next test.5. Significance and Use5.1 The cloud point of petroleum products and biodieselfuels is an index of the lowest temperature of their utility forcertain applications. Wax crystals
22、 of sufficient quantity canplug filters used in some fuel systems.5.2 Petroleum blending operations require precise measure-ment of the cloud point.5.3 This test method can determine the temperature of thetest specimen at which wax crystals have formed sufficiently tobe observed as a cloud with a re
23、solution of 0.1 C.5.4 This test method provides results that, when correctedfor bias and rounded to the next lower integer (see 12.2), havebeen found equivalent to Test Method D2500.5.5 This test method determines the cloud point in a shortertime period than required by Test Method D2500.6. Apparatu
24、s6.1 Automated Apparatus4The apparatus consists of amicroprocessor-controlled test specimen chamber that is ca-pable of heating and cooling the test specimen at required rates,optically observing the first appearance of hydrocarbon waxcrystals, and recording the temperature of the test specimenchamb
25、er. A detailed description of the apparatus is provided inAnnex A1.6.2 The apparatus shall be equipped with a thermostaticallycontrolled specimen chamber, digital display, cooling andheating systems, optical detection system, and a specimenchamber temperature measuring device.6.3 The temperature-mea
26、suring device in the specimenchamber shall be capable of measuring the temperature, atminimum, from 60 C to 60 C at a resolution of 0.1 C.7. Reagents and Materials7.1 Specimen VialDisposable, clear glass cylinder withclosed flat bottom, 1 mL capacity.NOTE 1Standard NWV type vial is suitable.Dimensio
27、ns:Outer diameter: 8.0 to 8.3 mmWall thickness: 0.75 to 0.85 mmOuter length: 39.25 to 40.25 mm7.2 Specimen Vial Stopper4Disposable, proprietary de-signed for use in this apparatus.7.3 MicropipetteCapable of delivering 0.5 mL 6 0.1 mLof sample. Positive displacement-type micropipette with cap-illary
28、piston is preferred for use. Air displacement-type mi-cropipettes are not recommended for viscous samples.8. Sampling8.1 Obtain a sample in accordance with Practice D4057 orD4177.8.2 At least 1 mL of sample is required for each test.8.3 Samples of very viscous materials may be warmed untilthey are r
29、easonably fluid before they are tested. However, nosample should be heated more than is absolutely necessary.8.4 The sample shall not be heated above 60 C. When thesample is heated above 60 C, allow the sample to cool below60 C before filtering or inserting into the apparatus.8.5 When moisture is pr
30、esent, remove the moisture by amethod such as filtration through dry, lint-free filter paper untilthe oil is perfectly clear, but make such filtration at a tempera-ture at least 14 C above the expected cloud point.NOTE 2Moisture will be noticed in the sample as a separate phase oras a haze throughou
31、t the entire sample. Generally, a slight haze will notinterfere with the detection of the wax cloud.9. Preparation of Apparatus9.1 Prepare the instrument for operation in accordance withthe manufacturers instructions.10. Calibration and Standardization10.1 Ensure that all of the manufacturers instru
32、ctions forcalibrating, checking, and operating the apparatus are fol-lowed.10.2 A sample with a well-documented cloud point can beused to verify the performance of the automatic apparatus.Alternatively, a sample that has been extensively tested in acloud point cross-check program can be used. Such v
33、erificationmaterials can also be prepared from intracompany cross-checks.4The sole source of supply of the apparatus (ISL Model MPP 5Gs analyzer)known to the committee at this time is ISL, B.P. 70825 14653, Verson, France. Ifyou are aware of alternative suppliers, please provide this information to
34、ASTMInternational Headquarters. Your comments will receive careful consideration at ameeting of the responsible technical committee,1which you may attend.D7689 172Mon Apr 30 54 11. Procedure11.1 Draw 0.5 mL 6 0.1 mL of sample into a micropipetteand transfer the specimen into a new clean, dry specime
35、n vial.When necessary, heat the sample in a water bath or oven untilit is just sufficiently fluid to transfer. Samples with an expectedcloud point (ECP) above 25 C or which appear solid at roomtemperature can be heated above 45 C but shall not be heatedabove 60 C.11.2 Place a new clean, dry specimen
36、 vial stopper on thespecimen vial and insert the assembly into the apparatus. Startthe operation of the apparatus according to the manufacturersinstructions.11.3 When the expected cloud point of the specimen isknown, program it in the apparatus as ECP (expected cloudpoint) and start test sequence. F
37、rom this point up to andincluding the termination of the test, recording and reporting ofthe result, the apparatus automatically controls the procedure.11.4 The apparatus shall adjust the specimen chamber to apreselected starting temperature. By default, the preselectedstarting temperature is 25 C.
38、Alternatively, the operator canpreprogram a defined starting temperature between 25 C and60 C, if desired. When the expected cloud point is known andprogrammed in the apparatus, the starting temperature shall beat least 10 C warmer than the expected cloud point. In theevent that the preselected star
39、ting temperature is programmedlower than 10 C above the programmed expected cloud point,the apparatus shall heat the specimen chamber to a startingtemperature at least 10 C above the expected cloud point, butnot more than 60 C. (WarningExercise care when selectingstarting temperatures above 40 C. Sa
40、mples which are fluid atambient room temperature can also have a low temperatureflash point. Use higher start temperatures only on samplesknown to be solid near ambient room temperature.)11.5 When the expected cloud point of the specimen is notknown, once the starting temperature is reached (see 11.
41、4) coolthe specimen chamber at a rate of 1.5 C 6 0.15 C min, whilethe optical system monitors for the appearance of the crystals.11.6 When the expected cloud point of the specimen isknown and programmed into the apparatus, once the startingtemperature (see 11.4) is reached, cool the specimen chamber
42、at a rate of 10 C 6 1 C min until 10 C warmer than theprogrammed expected cloud point, then adjust the cooling rateto 1.5 C 6 0.15 C min, while the optical system monitors forappearance of the crystals.11.7 When a cloud point is detected prematurely, during thefast cooling rate, as determined by the
43、 apparatus, reheat thespecimen to a higher starting temperature, at least 30 Cwarmer than the temperature of premature detection, and thencool as described in 11.5, while the optical system monitors forappearance of the crystals.11.8 At the detection of the cloud point, record the tempera-ture the s
44、pecimen attained, to within 0.1 C, which is held onthe digital display. Reheat the specimen to the preselectedstarting temperature.12. Report12.1 Report the temperature recorded in 11.8 to 0.1 C asthe cloud point D7689 (Mini Method).12.2 When specified, correct the temperature recorded in11.8 with t
45、he relative bias in accordance with 13.3, round theresult to the next lower integer (a colder temperature), andreport as the Test Method D2500 equivalent cloud point perTest Method D7689.13. Precision and Bias513.1 PrecisionThe precision of this test method as deter-mined by the statistical examinat
46、ion of the interlaboratory testresults is as follows:13.1.1 RepeatabilityThe difference between successivetest results, obtained by the same operator using the sameapparatus under constant operating conditions on identical testmaterial, would in the long run, in the normal and correctoperation of th
47、is test method, exceed Eq 1 only in one case intwenty (see Table 1).0.020630 C 2 X! valid range 2 50 to 16 C (1)where:X = cloud point (mini method).13.1.2 ReproducibilityThe difference between two singleand independent test results, obtained by different operatorsworking in different laboratories on
48、 identical test material,would in the long run, in normal and correct operation of thistest method, exceed Eq 2 only in one case in twenty (see Table1).0.056130 C 2 X! valid range 2 50 to 16 C (2)where:X = cloud point (mini method).13.2 BiasSince there is no accepted reference materialsuitable for d
49、etermining the bias for the procedure in this testmethod, bias has not been determined.13.3 Relative Bias (the Degree of Agreement Between Re-sults by Test Method D7689 and Test Method D2500/IP219)Results on the same materials produced by Test Method D76895Supporting data (the results of the 2009 Interlaboratory Cooperative TestProgram) have been filed at ASTM International Headquarters and may be obtainedby requesting Research Report RR:D02-1726. Contact ASTM Customer Service atserviceastm.org.TABLE 1
