1、Designation: D5771 12Designation: 444/99Standard Test Method forCloud Point of Petroleum Products (Optical DetectionStepped Cooling Method)1This standard is issued under the fixed designation D5771; the number immediately following the designation indicates the year oforiginal adoption or, in the ca
2、se 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.INTRODUCTIONThis test method describes an alternative procedure for the determination of cloud point o
3、fpetroleum products Test Method D2500/IP 219 using an automatic apparatus. The temperature resultsfrom 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 obt
4、aining comparative 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 an optical device.1.2 Thi
5、s test method covers the range of temperaturesfrom 60 to +49C with temperature resolution of 0.1C,however, the range of temperatures included in the 1997interlaboratory cooperative test program only covered thetemperature range of 56 to +34C.1.3 The values stated in SI units are to be regarded assta
6、ndard. 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 of this standard to establish appro-priate safety and health practices and determine the app
7、lica-bility 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 ProductsD6708 Prac
8、tice for StatisticalAssessment and Improvementof Expected Agreement Between Two Test Methods thatPurport to Measure the Same Property of a Material2.2 Energy Institute Standard:3IP 219 Test Method for Cloud Point of Petroleum Products32.3 Other Standard:4IEC 751 Industrial Platinum Resistance Thermo
9、meter Sen-sors3. Terminology3.1 Definitions:3.1.1 biodiesel, nfuel comprised of mono-alkyl esters oflong chain fatty acids derived from vegetable oils or animalfats, designated B 100.3.1.1.1 DiscussionBiodiesel is typically produced by areaction of vegetable oil or animal fat with an alcohol such as
10、methanol or ethanol in the presence of a catalyst to yieldmono-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, na blend of biodiesel fuel withpetroleum-based diesel f
11、uel designated BXX, where XX is thevolume % of biodiesel.1This 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 edition approved April 15, 2012. Published August 2012. Ori
12、ginallyapproved in 1995. Last previous edition approved in 2010 as D577110. DOI:10.1520/D5771-12.2For 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 Docum
13、ent Summary page onthe ASTM website.3Available from Energy Institute, 61 New Cavendish St., London, WIG 7AR,U.K., http:/www.energyinst.org.uk.4Available from International Electrotechnical Commission (IEC), 3 rue deVaremb, Case postale 131, CH-1211, Geneva 20, Switzerland, http:/www.iec.ch.1*A Summa
14、ry 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.3.1.3 cloud point, nin petroleum products and biodieselfuels, the temperature of a liquid specimen when the smallestobservable c
15、luster of hydrocarbon crystals 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
16、 specimen where thespecimen temperature is the lowest. The cloud point is thetemperature 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 typicall
17、y, but not excluded to, straightchain hydrocarbons commonly called “wax crystals.”3.1.3.2 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 be present. The intent of the cloud point
18、method is tocapture the temperature at which the liquids in the specimenbegin 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
19、Specific to This Standard:3.2.1 automatic cloud point, nthe temperature of a 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 detec
20、tion of the crystal formation. The apparatus and theconditions are different from those established for Test MethodD2500, although, according to interlaboratory examination theresults have been determined to be equivalent to Test MethodD2500.3.2.2 optical detection stepped cooling method, nin cloudp
21、oint test methods, test procedure using prescribed coolingrate, specimen receptacle, and optical system for detection ofcrystal formation.3.2.2.1 DiscussionThe prescribed cooling rate is de-scribed in 4.1; the specimen receptacle is described in Section6, and the optical system for the detection of
22、crystal formationis described in Section 6.3.2.3 D2500/IP 219 equivalent cloud point, nthe 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
23、 wish to provide results witha similar format to Test Method D2500, then this calculationcan be performed. Some apparatus can perform this calculationautomatically.4. Summary of Test Method4.1 After insertion of the prescribed test jar (6.3) containingthe specimen into the apparatus, and the initiat
24、ion of theprogram, the specimen is cooled incrementally according to thecooling profile listed in Table 1. The specimen is continuouslymonitored by a reflective optical system (6.1 and Fig. 1) for theformation of a crystalline structure. When the crystallization ofTABLE 1 Jacket and Specimen Cooling
25、 TemperaturesSpecimen Temperature, C Jacket Temperature, CST+10 06 0.5+10$ ST 7 17.26 0.57 $ ST 24 34.2 6 0.524 $ ST 41 51.26 0.541 $ ST 58 68.26 0.558 $ ST 75 85.26 0.5D5771 122the wax in the specimen is detected by the optical system, thetemperature is recorded to within 0.1C resolution. The speci
26、-men is then heated to facilitate the start of the next test.5. Significance and Use5.1 For petroleum products and biodiesel fuels, the cloudpoint is an index of the lowest temperature of their utility forcertain applications. Wax crystals of sufficient quantity canplug filters used in some fuel sys
27、tems.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 resolution of 0.1C.5.4 This test method provides results that,
28、when rounded tothe next lower integer, are equivalent to Test Method D2500.Refer to 12.2.5.5 This test method is more precise than Test MethodD2500.NOTE 1According to interlaboratory examination, the reproducibilityof this test method has been found to be more precise than Test MethodD2500.6. Appara
29、tus6.1 Optical Cloud Point Apparatus5The automated cloudpoint apparatus (see Fig. 2) described in this test methodconsists of a microprocessor controller that is capable ofcontrolling one or more independent test cells. The apparatusshall include provisions for independently controlling thetemperatu
30、re of each cell according to the specified coolingprofile, continuously monitoring the specimen temperature,detecting the appearance of the cloud point at the bottom of thetest jar without removing it from the jacket, and displaying the0.1 or 1.0C result (see Fig. 1 and Fig. 3).6.2 Temperature Probe
31、, IEC 751 Class A: DT=6(0.15 +0.002 |T|), capable of measurement from 50 to +80C. Thetemperature probe shall be in contact with the bottom of thetest jar.6.3 Test Jar, clear cylindrical glass, mirrored flat bottom, 346 0.5-mm outside diameter, 1.4 6 0.15 mm wall thickness,120 6 0.5-mm height, thickn
32、ess of the bottom 2.0 6 0.5 mm,marked with a line to indicate the sample height 54 6 0.5 mmabove the inside bottom.6.4 Jacket, brass, cylindrical, flat bottom, 113 6 0.2 mm indepth, 45 6 0.1-mm inside diameter. It must be cooledaccording to the cooling profile specified.6.5 Cooling System, either an
33、 external system equipped witha circulating pump and capable of maintaining a temperature atleast 10C below the last required jacket temperature level (seeTable 1 and Fig. 3), or an internal system capable of maintain-ing the required jacket temperatures (see Table 1 and Fig. 3).6.6 Cork Disk,66 0.2
34、 mm thick, to fit loosely inside thejacket. Felt may be used but special attention must be given tothe potential for moisture in the felt disk. The felt must be driedbefore each test.6.7 Cork Ring, to fit snugly around the outside of the test jarand loosely inside the sample cell. Its purpose is to
35、prevent thetest jar from touching the jacket.7. Reagents and Materials7.1 Cleaning Solvents, suitable for cleaning and drying thetest cell, such as petroleum naphtha and hexane.7.2 Methyl Alcohol, Anhydrous, for use as cooling mediumin circulating bath cooling system, when used.7.3 Sodium SulfateA r
36、eagent grade of anhydrous sodiumsulfate should be used when required. (WarningFlammable.Liquid causes eye burns. Vapor harmful. May be fatal or causeblindness if swallowed or inhaled.)5The sole source of supply of the ISL Model CPP97-6 and CPP97-2 andCPP-5Gs known to the committee at this time is IS
37、L SA, BP 40, 14790 Verson,France. If you are aware of alternative suppliers, please provide this information toASTM International Headquarters. Your comments will receive careful consider-ation at a meeting of the responsible technical committee,1which you may attend.FIG. 1 Test Jar and Detection Sy
38、stemD5771 1238. Sampling8.1 Obtain a sample in accordance with Practices D4057 orby D4177.8.2 Samples of very viscous materials may be warmed untilthey are reasonably fluid before they are sampled. However, nosample should be heated more than is absolutely necessary.FIG. 2 Automated Cloud Point Appa
39、ratusD5771 1248.3 The sample shall not be heated above 70C. If 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
40、paper, until the oil is perfectly clear, but make suchfiltration at a temperature at least 14C above the expectedcloud point.NOTE 2A wax cloud or haze is always noted at the bottom of the testjar where the temperature is lowest. A slight haze throughout the entirespecimen, which slowly becomes more
41、apparent as the temperature islowered, is usually due to water in the specimen. Generally this water hazewill not interfere with the determination of the wax cloud point. In mostcases of interference, filtration through dry lint-free filter papers such asdescribed in 11.2 is sufficient.8.5 For diese
42、l fuels, if the haze is very dense, a fresh portionof sample must be dried by shaking 100 mL with5gofanhydrous sodium sulfate for at least 5 min and then filteringthrough dry lint-free filter paper. Given sufficient contact time,this procedure will remove or sufficiently reduce the water hazeso that
43、 the wax cloud can be readily discerned. Drying andfiltering should always be done at a temperature at least 14Cabove the approximate cloud point, but otherwise not in excessof 49C.9. Preparation of Apparatus9.1 Prepare the instrument for operation in accordance withthe manufacturers instructions.9.
44、2 Clean and dry the test head and test jar using suitablesolvents as prescribed by the manufacturer.9.3 Adjust the set point of the cooling system, whennecessary, to the appropriate temperature to cool the jacket tothe required temperature (see Table 1).10. Calibration and Standardization10.1 Ensure
45、 that all of the manufacturers instructions forcalibrating, checking, and operating the apparatus are fol-lowed.10.1.1 Atest head simulator with a known resistance is usedto calibrate the equipment. Follow the manufacturers calibra-tion instructions.NOTE 3A test head simulator may be obtained from t
46、he apparatussupplier which can assist in verification of temperature measurement.10.2 A sample with a mutually agreed upon cloud pointsuch as a sample from a interlaboratory test program can beused to verify performance of the apparatus.11. Procedure11.1 Set the temperature unit on the apparatus to
47、1C or to0.1C.NOTE 4The temperature unit, in common laboratory practice, is 1C.If a higher resolution is desired, 0.1C can be selected.11.2 Using a water bath or oven, bring the sample to betested to a temperature at least 14C above the expected cloudpoint. When moisture is present in the sample, rem
48、ove themoisture present by a method, such as filtration through drylint-free filter paper, until the sample is perfectly clear, butmake such filtration at a temperature of at least 14C above theapproximate cloud point but otherwise not in excess of 70C.11.3 Pour the clear sample into the test jar to
49、 the level mark.11.4 Place a cork disk at the bottom of the jacket in theappropriate cell and fit a cork ring around the test jar. Use thecork placement guide, if necessary, for the final adjustment.The cork ring must be 25 6 3.0 mm above the bottom of thetest jar.NOTE 5A cork placement guide may be obtained from the apparatussupplier which can assist in proper placement of the cork ring.11.5 Place the test jar in the appropriate test cell. Attach thedetector head according to the manufacturers instructions.
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