1、Designation: D 5772 05Designation: 445/99An American National StandardStandard Test Method forCloud Point of Petroleum Products (Linear Cooling RateMethod)1This standard is issued under the fixed designation D 5772; the number immediately following the designation indicates the year oforiginal adopt
2、ion or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.INTRODUCTIONThis test method describes an alternative procedure for the determinatio
3、n of cloud point ofpetroleum products of Test Method D 2500/IP 219 using an automatic apparatus. The temperatureresults from this test method have been found to be equivalent to Test Method D 2500/IP 219. Whenspecification requires Test Method D 2500/IP 219, do not substitute this test method or any
4、 othermethod without obtaining comparative data and agreement from the specifier.1. Scope*1.1 This test method describes the determination of thecloud point of petroleum products and biodiesel fuels that aretransparent in layers 40 mm in thickness by an automaticinstrument using a linear cooling rat
5、e.1.2 This test method 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 regard
6、ed as thestandard. The values given in parentheses are for informationonly.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 determin
7、e the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 2500 Test Method for Cloud Point of Petroleum ProductsD 4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD 4177 Practice for Automatic Sampling of Petroleum andPetroleum Produc
8、ts2.2 Energy Institute 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
9、produced by areaction 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
10、.1.2 biodiesel blend, 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 crystal
11、s first occurs uponcooling 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 thespecimen t
12、emperature is the lowest. The cloud point is thetemperature at which the crystals first occur, regardless of their1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.07 on Flow Properties.Current ed
13、ition approved July 1, 2005. Published August 2005. Originallyapproved in 1995. Last previous edition approved in 2004 as D 577204.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume informa
14、tion, refer to the standards Document Summary page onthe ASTM website.3Available from Energy Institute, 61 New Cavendish St., London, WIG 7AR,U.K.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
15、 19428-2959, United States.location 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.”3.1.3.2 DiscussionThe purpose of t
16、he 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 to change from a single liqu
17、id 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 speci-men when the appearance
18、 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 from those established for Te
19、st MethodD 2500, although, according to interlaboratory examination,the results have been determined to be equivalent to TestMethod D 2500.3.2.2 D 2500/IP 219 equivalent cloud point, nthe tem-perature of a specimen, in integers, calculated by rounding theresults of this test method to the next lower
20、 integer.3.2.2.1 DiscussionThis test method produces results with0.1C resolution. Should the user wish to provide results witha similar format to Test Method D 2500, then this calculationcan be performed. Some apparatus can perform this calculationautomatically.4. Summary of Test Method4.1 After ins
21、ertion of the specimen into the apparatus andinitiation of the program, the specimen is heated and thencooled at a specified rate. The specimen is continuouslymonitored by an optical light barrier for the crystal structureformation. The temperature, when the crystallization of thewax in the specimen
22、 is detected by the optical barrier, isrecorded with a resolution of 0.1C. The specimen is thenheated to 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.
23、Wax crystals of sufficient quantity can plug filtersused 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 clo
24、ud, with a resolution of 0.1C.5.4 This test method provides results that when rounded tothe next lower integer are equivalent to Test Method D 2500.5.5 This test method is more precise than Test MethodD 2500.6. Apparatus6.1 Automatic Apparatus4The automatic cloud point ap-paratus described in Annex
25、A1 consists of a microprocessor-controlled measuring unit that is capable of heating, cooling,optically observing 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
26、light barrier assembly, and atest cell of the approximate dimensions listed inAnnexA1, andcontain a temperature 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 wi
27、th acirculating pump capable of maintaining a temperature at least20C lower than the lowest expected cloud 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 bu
28、rns. Vapor is harmful. May befatal or cause blindness if swallowed or inhaled.)7.2 Methyl Alcohol, anhydrous, for use as cooling mediumin circulating bath.8. Sampling8.1 Obtain a sample in accordance with Practices D 4057 orD 4177.8.2 Samples of very viscous materials may be warmed untilthey are rea
29、sonably fluid before they are sampled. However, nosample should be heated more than absolutely necessary.8.3 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 i
30、n the sample, remove themoisture by a method such as filtration through dry lint-freefilter paper until the 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
31、 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.9.2 Clean and dry the test cell using suitable solvents asprescribed by the manufact
32、urer.9.3 Prepare the refrigerated 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.4The sole source of supply of the Herzog Model SC 815 and SC 819 known tothe committee a
33、t 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 theresponsible technical committee,1which you may attend.D577205210. Calibration
34、 and Standardization10.1 Ensure that all of the manufacturers instructions forcalibrating, checking, and operating the apparatus are fol-lowed.10.2 A sample 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 i
35、nto the beaker.When necessary, heat the sample in a water bath or oven untilit is just sufficiently fluid to 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
36、 to be above25C, preselect a starting temperature which is at least 14Cabove the expected cloud point. The highest 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 temper
37、ature which is at least 14C above theexpected cloud point. The lowest starting temperature that canbe programmed 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 startingtemp
38、erature is not selected. When the expected cloud point isnot known and the sample needs to be heated before 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
39、startingtemperature preselected by the operator between 20 and 70C.The flow of the cooling fluid from the circulating 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 spec
40、imentemperature is continuously displayed. At the detection of theautomatic cloud point, the temperature the 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 2Al
41、though the apparatus is capable of faster cooling rates of 2or 3C/min, the interlaboratory program does not 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 manufacture
42、rsinstructions.NOTE 3Some apparatus is capable of automatic cleaning of the testcell and automatic sample changing.12. Report12.1 Report the temperature recorded in 11.6 as the auto-matic cloud point Test Method D 5772.12.2 When specified, round the temperature recorded in11.6 to the next lower inte
43、ger and report as the D 2500equivalent cloud point in accordance with Test MethodD 5772.13. Precision and Bias13.1 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 su
44、ccessivetest 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 this test method, exceed 1.3C only in one case intwenty.13.1.2 ReproducibilityThe difference between t
45、wo singleand independent test results obtained by different operatorsworking in different laboratories on identical 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 1
46、997interlaboratory cooperative test program.6Participants ana-lyzed eleven sample sets, as blind duplicates, comprised ofvarious distillate fuels and lubricating oils with a temperaturerange from +34 to 56C. Five laboratories participated withthe automatic apparatus and eight laboratories participat
47、ed withthe manual Test Method D 2500/IP 219 test method. Informa-tion on the type of samples and their average 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 deter
48、mined.13.3 Relative BiasThe results of the interlaboratory pro-gram were examined for bias relative to Test Method D 2500/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 Biodi
49、esel ProductsThe precision ofthis test method, as determined by the statistical examination ofthe interlaboratory test results, is as follows:13.4.1 Repeatability for Biodiesel in Diesel BlendsThedifference between successive test results, obtained by thesame operator using the same apparatus under constant oper-ating conditions on identical test material, would, in the longrun, in the normal and correct operation of this test method,exceed 0.7C only in one case in twenty.13.4.2 Reproducibility for Biodiesel in Diesel Blend
