1、Designation: D 5771 05Designation: 444/99An American National StandardStandard Test Method forCloud Point of Petroleum Products (Optical DetectionStepped Cooling Method)1This standard is issued under the fixed designation D 5771; the number immediately following the designation indicates the year of
2、original adoption 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 th
3、e determination of cloud point ofpetroleum products Test Method D 2500 using an automatic apparatus. The temperature results fromthis test method have been found to be equivalent to Test Method D 2500. When specification requiresTest Method D 2500, do not substitute this test method or any other met
4、hod without obtainingcomparative 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 an optical device.1.2 This te
5、st 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 as thesta
6、ndard. 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 determine the applic
7、a-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 Products2.2 Energy
8、 Institute Standard:3IP 219 Test Method for Cloud Point of Petroleum Products32.3 Other Standard:4IEC 751 Industrial Platinum Resistance Thermometer Sen-sors3. Terminology3.1 Definitions:3.1.1 biodiesel, nfuel comprised of mono-alkyl esters oflong chain fatty acids derived from vegetable oils or ani
9、malfats, designated B 100.3.1.1.1 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 different types of fatty acids tha
10、t are chemically transformedinto fatty acid methyl esters (FAME).3.1.2 biodiesel blend, na blend of biodiesel fuel withpetroleum-based diesel fuel designated BXX, where XX is thevolume % of biodiesel.3.1.3 cloud point, nin petroleum products and biodieselfuels, the temperature of a liquid specimen w
11、hen the smallestobservable cluster 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 hydrocarbon1This test method is under the jurisdiction of ASTM Committee D02 onPetrole
12、um Products and Lubricants and is the direct responsibility of SubcommitteeD02.07 on Flow Properties.Current edition approved July 1, 2005. Published August 2005. Originallyapproved in 1995. Last previous edition approved in 2004 as D 577104.2For referenced ASTM standards, visit the ASTM website, ww
13、w.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 the Energy Institute, 61 New Cavendish St., London, EnglandWIG 7AR, U.K.4Available from International E
14、lectrotechnical Commission, P.O. 131, 3 Rue deVarembe, CH-Geneve 12112.0.1*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.crystals to precipitate. In a homogeneous liqu
15、id, the cloud isalways noted first at the location in the 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 cr
16、ystals that precipitate atlower temperatures are typically, 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 inorgani
17、c compoundsmay be present. The intent of the cloud point 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
18、 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 of the cloud is determined under theconditions of this test method.3.2.1.1 DiscussionThe cloud point in this test method isdetermined by
19、 an automatic instrument using an optical devicefor detection of the crystal formation. The apparatus and theconditions are different from those established for Test MethodD 2500, although, according to interlaboratory examination theresults have been determined to be equivalent to Test MethodD 2500
20、.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 integer.3.2.2.1 DiscussionThis test method produces results with0.1C resolution. Should the user wish to provide results witha similar fo
21、rmat to Test Method D 2500, then this calculationcan be performed. Some apparatus can perform this calculationautomatically.4. Summary of Test Method4.1 After insertion of the specimen into the apparatus, andthe initiation of the program, the specimen is cooled accordingto the cooling profile listed
22、 in Table 1. The specimen iscontinuously monitored by an optical system for the formationof a crystalline structure.When the crystallization of the wax inthe specimen is detected by the optical system, the temperatureis recorded to within 0.1C resolution. The specimen is thenheated to facilitate the
23、 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 systems.5.2 Petroleum blending operation
24、s 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.TABLE 1 Jacket and Specimen Cooling TemperaturesSpecimen Temperature, C Jacket Te
25、mperature, 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 0.5D57710525.4 This test method provides results that, when rounded tothe next lower integer, are equivalent to Test Method D 2500.Refer to 12.2.5.5 This test method is more precis
26、e than Test MethodD 2500.NOTE 1According to interlaboratory examination, the reproducibilityof this test method has been found to be more precise than Test MethodD 2500.6. Apparatus6.1 Optical Cloud Point Apparatus5The automated cloudpoint apparatus (see Fig. 1) described in this test methodconsists
27、 of a microprocessor controller that is capable ofcontrolling one or more independent test cells. The apparatusshall include provisions for independently controlling thetemperature of each cell according to the specified coolingprofile, continuously monitoring the specimen temperature,detecting the
28、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. 2 and Fig. 3).6.2 Temperature Probe, IEC 751 Class A: DT=6(0.15 +0.002 |T|), capable of measurement from 50 to +80C. Thetemperature probe shall be in contact
29、 with the bottom of thetest jar.6.3 Test Jar, clear cylindrical glass, mirrored flat bottom, 346 0.1-mm outside diameter, 31 6 0.3-mm inside diameter, 1206 0.5-mm height, thickness 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 Jack
30、et, 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.5The sole source of supply of the ISL Model CPP97-6 and CPP97-2 known tothe committee at this time is ISL North America, Stevensville, MD or ISL SA, BP4
31、0, 14790 Verson, France. If you are aware of alternative suppliers, please providethis information to ASTM International Headquarters. Your comments will receivecareful consideration at a meeting of the responsible technical committee1, whichyou may attend.FIG. 1 Automated Cloud Point ApparatusFIG.
32、2 Test Jar and Detection SystemD57710536.5 Cooling Circulating Bath, equipped with a circulatingpump and capable of maintaining a temperature at least 10Cbelow the last required jacket temperature level (see Table 1).6.6 Cork Disk,66 0.2 mm thick, to fit loosely inside thejacket. Felt may be used bu
33、t 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 prevent thetest jar from touching the jacket.7. Reagents and Ma
34、terials7.1 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.7.3 Sodium SulfateA reagent grade of anhydrous sodiumsulfate should be used when required. (WarningFlammable.L
35、iquid causes eye burns. Vapor harmful. May be fatal or causeblindness if swallowed or inhaled.)8. Sampling8.1 Obtain a sample in accordance with Practices D 4057 orby D 4177.8.2 Samples of very viscous materials may be warmed untilthey are reasonably fluid before they are sampled. However, nosample
36、should be heated more than is absolutely necessary.8.3 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 fi
37、ltration through dry lint-freefilter 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 entir
38、especimen, which slowly becomes more 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 asdescribe
39、d in 11.2 is sufficient.8.5 For diesel 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 suff
40、iciently reduce the water hazeso that 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
41、withthe manufacturers instructions.9.2 Clean and dry the test head and test jar using suitablesolvents as prescribed by the manufacturer.9.3 Adjust the set point of the recirculating cooler to theappropriate temperature to cool the jacket to the requiredtemperature (see Table 1).10. Calibration and
42、Standardization10.1 Ensure 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 simula
43、tor may be obtained from the 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
44、 unit on the apparatus to 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
45、present in the sample, remove 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 s
46、ample into the test jar to 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 theFIG. 3 Test Jar Cooling Chamber and Circulating BathD5771054cork placement guide, if necessary, for the final adjustment.The cork ring m
47、ust 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.1
48、1.6 Start the test according to the manufacturers instruc-tions. The instrument shall then automatically adjust the jackettemperature in accordance with Table 1 and begin to opticallymonitor the specimen for the cloud point. The instrument shallmonitor and display the jacket temperature and the spec
49、imentemperature during the test procedure.11.7 The instrument shall continue to monitor and adjust thejacket temperature according to Table 1. At no point shall thetime to move from one jacket temperature level to the nextjacket temperature level exceed 90 s.11.8 The instrument shall detect the cloud point at thebottom of the test jar and record and display the temperature asselected in 11.1. The instrument shall have an audible alarm,such that when a cloud point is detected, it immediately notifiesthe operator. Th
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