1、Designation: D5772 10Designation: 445/99Standard Test Method forCloud Point of Petroleum Products (Linear Cooling RateMethod)1This standard is issued under the fixed designation D5772; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision
2、, 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.INTRODUCTIONThis test method describes an alternative procedure for the determination of cloud point ofpetroleum pro
3、ducts of Test Method D2500/IP 219 using an automatic apparatus. The temperatureresults from this test method have been found to be equivalent to Test Method D2500/IP 219. Whenspecification requires Test Method D2500/IP 219, do not substitute this test method or any othermethod without obtaining comp
4、arative data and agreement from the specifier.1. Scope*1.1 This test method covers the description of the determi-nation of the cloud point of petroleum products and biodieselfuels that are transparent in layers 40 mm in thickness by anautomatic instrument using a linear cooling rate.1.2 This test m
5、ethod covers the range of temperatures from60 to 49C with temperature resolution of 0.1C, however,the range of temperatures included in the 1997 interlaboratorycooperative test program only covered the temperature range of56 to +34C.1.3 The values stated in SI units are to be regarded asstandard. No
6、 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 of this standard to establish appro-priate safety and health practices and determine the applica-bili
7、ty of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D2500 Test Method for Cloud Point of Petroleum ProductsD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of Petroleum andPetroleum Products2.2 Energy Institut
8、e Standard:IP 219 Test Method for Cloud Point of Petroleum Products33. Terminology3.1 Definitions:3.1.1 biodiesel, na fuel comprised of mono-alkyl esters oflong-chain fatty acids derived from vegetable oils or animalfats, designated B100.3.1.1.1 DiscussionBiodiesel is typically produced by areaction
9、 of vegetable oil or animal fat with an alcohol such asmethanol or ethanol in the presence of a catalyst to yield-mono-esters and glycerin. The fuel typically may contain up to14 different types of fatty acids that are chemically transformedinto fatty acid methyl esters (FAME).3.1.2 biodiesel blend,
10、 na blend of biodiesel fuel withpetroleum-based diesel fuel designated BXX, where XX is thevolume percentage of biodiesel.3.1.3 cloud point, nin petroleum products and biodieselfuels, the temperature of a liquid specimen when the smallestobservable cluster of hydrocarbon crystals first occurs uponco
11、oling under prescribed conditions.3.1.3.1 DiscussionThe cloud point occurs when the tem-perature of the specimen is low enough to cause hydrocarboncrystals to precipitate. In a homogeneous liquid, the cloud isalways noted first at the location in the specimen where the1This test method is under the
12、jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.07 on Flow Properties.Current edition approved May 1, 2010. Published August 2010. Originallyapproved in 1995. Last previous edition approved in 2005 as D577205. DOI:10.1520/D57
13、72-10.2For 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 standards Document Summary page onthe ASTM website.3Available from Energy Institute, 61 New Cavendish St.,
14、 London, WIG 7AR,U.K., http:/www.energyinst.org.uk.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.specimen temperature is the lowest. The cloud point is thetemperatur
15、e at which the crystals first occur, regardless of theirlocation in the specimen, and not after extensive crystallizationhas taken place. The hydrocarbon crystals that precipitate atlower temperatures are typically, but not excluded to, straightchain hydrocarbons commonly called “wax crystals.”3.1.3
16、.2 DiscussionThe purpose of the cloud point methodis to detect the presence of the wax crystals in the specimen;however, trace amounts of water and inorganic compoundsmay also be present. The intent of the cloud point method is tocapture the temperature at which the liquid fuel in the specimenbegins
17、 to change from a single liquid phase to a two-phasesystem containing solid and liquid. It is not the intent of thistest method to monitor the phase transition of the tracecomponents, such as water.3.2 Definitions of Terms Specific to This Standard:3.2.1 automatic cloud point, nthe temperature of a
18、speci-men when the appearance of the cloud is determined under theconditions of this test method.3.2.1.1 DiscussionThe cloud point in this test method isdetermined by an automatic instrument using an optical devicefor detection of the crystal formation. The apparatus and theconditions are different
19、from those established for Test MethodD2500, although, according to interlaboratory examination, theresults have been determined to be equivalent to Test MethodD2500.3.2.2 linear cooling rate method, nin cloud point testmethods, test procedure using prescribed cooling rate, speci-men receptacle, and
20、 optical system for detection of crystalformation.3.2.2.1 DiscussionThe prescribed cooling rate is de-scribed in 11.6; the specimen receptacle is described in AnnexA1, and the optical system for the detection of crystal forma-tion is described in Annex A1.3.2.3 D2500/IP 219 equivalent cloud point, n
21、the tempera-ture of a specimen, in integers, calculated by rounding theresults of this test method to the next lower integer.3.2.3.1 DiscussionThis test method produces results with0.1C resolution. Should the user wish to provide results witha similar format to Test Method D2500, then this calculati
22、oncan be performed. Some apparatus can perform this calculationautomatically.4. Summary of Test Method4.1 After insertion of the specimen into the apparatus andinitiation of the program, the prescribed specimen test cell(Annex A1) is heated and then linearly cooled at a specifiedrate (11.6). The spe
23、cimen is continuously monitored by anopposing optical light barrier (AnnexA1 and Fig.A1.3) for thecrystal structure formation. The temperature, when the crystal-lization of the wax in the specimen is detected by the opticalbarrier, is recorded with a resolution of 0.1C. The specimen isthen heated to
24、 the original starting temperature.5. Significance and Use5.1 For petroleum products and diesel fuels, the cloud pointis an index of the lowest temperature of its utility for certainapplications. Wax crystals of sufficient quantity can plug filtersused in some fuel systems.5.2 Petroleum blending ope
25、rations 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 resolution of 0.1C.5.4 This test method provides results that when rounded tothe next lower i
26、nteger are equivalent to Test Method D2500.5.5 This test method is more precise than Test MethodD2500.6. Apparatus6.1 Automatic Apparatus4The automatic cloud point ap-paratus described in Annex A1 consists of a microprocessor-controlled measuring unit that is capable of heating, cooling,optically ob
27、serving the appearance of the automatic cloudpoint, and recording the temperature of the specimen. Theapparatus shall be equipped with a digital display, cooling/heating block assembly, optical light barrier assembly, and atest cell of the approximate dimensions listed inAnnexA1, andcontain a temper
28、ature measuring device.6.2 Beaker, glass or plastic (disposable) (50 mL), forcontaining the sample prior to introduction into the test cell.6.3 Circulating Bath, a refrigeration unit equipped with acirculating pump capable of maintaining a temperature at least20C lower than the lowest expected cloud
29、 point to bemeasured.7. Reagents and Materials7.1 Cleaning Solvents, suitable for cleaning and drying thetest cell, such as petroleum naphtha and acetone. (WarningFlammable. Liquid causes eye burns. Vapor is harmful. May befatal or cause blindness if swallowed or inhaled.)7.2 Methyl Alcohol, anhydro
30、us, for use as cooling mediumin circulating bath.8. Sampling8.1 Obtain a sample in accordance with Practices D4057 orD4177.8.2 Samples of very viscous materials may be warmed untilthey are reasonably fluid before they are sampled. However, nosample should be heated more than absolutely necessary.8.3
31、 The sample shall not be heated above 70C. When thesample is heated above 70C, allow the sample to cool below70C before filtering or inserting into the apparatus.8.4 When moisture is present in the sample, remove themoisture by a method such as filtration through dry lint-freefilter paper until the
32、oil is perfectly clear. Make such filtrationat a temperature at least 14C above the expected cloud point.NOTE 1Moisture will be noticed in the sample as a separate phase oras a haze throughout the entire sample. Generally, a slight haze will notinterfere with the detection of the wax cloud.4The sole
33、 source of supply of the Herzog Model SC 815 and SC 819 known tothe committee at this time is Walter Herzog, Lauda, Germany. If you are aware ofalternative suppliers, please provide this information to ASTM InternationalHeadquarters. Your comments will receive careful consideration at a meeting of t
34、heresponsible technical committee,1which you may attend.D5772 1029. Preparation of Apparatus9.1 Prepare the instrument for operation in accordance withthe manufacturers instructions.9.2 Clean and dry the test cell using suitable solvents asprescribed by the manufacturer.9.3 Prepare the refrigerated
35、circulating bath for operation inaccordance with the manufacturers instructions and allow it toattain a temperature at least 20C lower than the expectedcloud point of the sample.10. Calibration and Standardization10.1 Ensure that all of the manufacturers instructions forcalibrating, checking, and op
36、erating the apparatus are fol-lowed.10.2 Asample with a mutually agreed upon cloud point canbe used to verify performance of the apparatus.11. Procedure11.1 Pour at least 20 mL of the sample into the beaker.When necessary, heat the sample in a water bath or oven untilit is just sufficiently fluid to
37、 pour into the beaker.11.2 Place the beaker under the entrance of the test cell andstart the test in accordance with the manufacturers instruc-tions.11.3 When the expected cloud point is known to be above25C, preselect a starting temperature which is at least 14Cabove the expected cloud point. The h
38、ighest starting tempera-ture that can be programmed is 70C.11.4 When the expected cloud point is known to be at orbelow 25C, the test duration can be shortened by preselectinga starting temperature which is at least 14C above theexpected cloud point. The lowest starting temperature that canbe progra
39、mmed is 20C.11.5 When the expected cloud point is not known, preselecta starting temperature of 40C. The apparatus automaticallyheats the test specimen to approximately 40C when a startingtemperature is not selected. When the expected cloud point isnot known and the sample needs to be heated before
40、transfer-ring into the test specimen beaker, preselect a starting tempera-ture of 70C.11.6 A portion of the sample is drawn into the test cell.Initially, the specimen is heated to 40C or to a startingtemperature preselected by the operator between 20 and 70C.The flow of the cooling fluid from the ci
41、rculating bath is thenregulated to maintain the rate of cooling of the specimen at 16 0.2C per min (see Note 2). The specimen is continuouslymonitored by the optical light barrier and the specimentemperature is continuously displayed. At the detection of theautomatic cloud point, the temperature the
42、 specimen attained,to within 0.1C resolution, is held on the digital display untilcleared by the operator. The specimen is then heated to 40C orto the preselected starting temperature.NOTE 2Although the apparatus is capable of faster cooling rates of 2or 3C/min, the interlaboratory program does not
43、address the equivalencyand precision of results using these cooling rates.11.7 Clean the test cell by flushing solvents through the celland then dry with clean air according to the manufacturersinstructions.NOTE 3Some apparatus is capable of automatic cleaning of the testcell and automatic sample ch
44、anging.12. Report12.1 Report the temperature recorded in 11.6 as the auto-matic cloud point Test Method D5772.12.2 When specified, round the temperature recorded in11.6 to the next lower integer and report as the D2500equivalent cloud point in accordance with Test Method D5772.13. Precision and Bias
45、13.1 PrecisionThe precision of this test method as deter-mined by the statistical examination of the interlaboratory testresults5,6is as follows:13.1.1 RepeatabilityThe difference between successivetest results obtained by the same operator using the sameapparatus under constant operating conditions
46、 on identical testmaterial would in the long run, in the normal and correctoperation of this test method, exceed 1.3C only in one case intwenty.13.1.2 ReproducibilityThe difference between two singleand independent test results obtained by different operatorsworking in different laboratories on iden
47、tical test materialwould in the long run, in the normal and correct operation ofthis test method, exceed 3.3C only in one case in twenty.13.1.3 The precision statements were derived from a 1997interlaboratory cooperative test program.6Participants ana-lyzed eleven sample sets, as blind duplicates, c
48、omprised ofvarious distillate fuels and lubricating oils with a temperaturerange from +34 to 56C. Five laboratories participated withthe automatic apparatus and eight laboratories participated withthe manual Test Method D2500/IP 219 test method. Informa-tion on the type of samples and their average
49、cloud points arein the research report.513.2 BiasSince there is no accepted reference materialsuitable for determining the bias for the procedure in this testmethod, bias has not been determined.13.3 Relative BiasThe results of the interlaboratory pro-gram were examined for bias relative to Test Method D2500/IP 219.Although statistically significant bias was observed, themagnitude was determined to be small enough (0.67C) to beof little practical significance.13.4 Precision for Biodiesel ProductsThe precision ofthis test
