1、Designation:D768311Standard Test Method forCloud Point of Petroleum Products(Small Test Jar Method)1This standard is issued under the fixed designation D7683;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A
2、 number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of the cloudpoint of petroleum products,biodiesel,and biodiesel blendsthat are transparent in la
3、yers 40 mm in thickness,using anautomatic instrument.1.2 The measuring range of the apparatus is from-65 to51C,however the precision statements were derived onlyfrom samples with cloud point temperatures from-50 to+6C.1.3 The values stated in SI units are to be regarded asstandard.No other units of
4、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-bility of regulatory li
5、mitations 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 Practice for Statistical Assessme
6、nt and Improvementof Expected Agreement Between Two Test Methods thatPurport to Measure the Same Property of a Material2.2 Energy Institute Standards:3IP219 Test Method for Cloud Point of Petroleum Products3.Terminology3.1 Definitions:3.1.1 biodiesel,nfuel comprising mono-alkyl esters oflong-chain f
7、atty acids derived 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
8、up to14 different 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.
9、3 cloud point,n in petroleum products and biodieselfuels,the temperature of a liquid specimen when 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
10、to cause hydrocarboncrystals to precipitate.In a homogeneous liquid,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
11、 extensive crystallizationhas taken place.The hydrocarbon crystals that precipitate atlower temperatures are typically,but not excluded to,straightchain hydrocarbons commonly called“wax crystals.”3.2 Definitions of Terms Specific to This Standard:3.2.1 small test jar method,nin cloud point test meth
12、ods,automatic test procedure using a small sample size,prescribedcooling rate,specimen receptacle,and optical system fordetection of crystal formation.3.2.1.1 DiscussionThe prescribed cooling rate is de-scribed in 11.4,the specimen receptacle is described in 6.3,andthe optical system for detection o
13、f crystal formation is de-scribed in A1.2.3.3.2.2 D2500/IP219 equivalent cloud point,ntemperatureof a specimen,in integers,calculated by applying a bias androunding the results of this test method to the next lowerinteger(see 12.2).3.2.2.1 DiscussionThis test method produces results with0.1C resolut
14、ion.Should the user wish to provide results with1This 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 edition approved Feb.15,2011.Published April 2011.DOI:1
15、0.1520/D768311.2For 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 S
16、t.,London,WIG 7AR,U.K.,http:/www.energyinst.org.uk.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 a similar format to Test Method D2500,then this calculationcan be performed.Some apparatus can perform this calculationautomatically.4.Summary of Test Method4.1 After inserting the glass test jar containing the specimeninto the automatic apparatus and initiating the test program,thespecimen is heated,if necessary,to the designated temper
