1、Designation:D768921Standard Test Method forCloud Point of Petroleum Products and Liquid Fuels(MiniMethod)1This standard is issued under the fixed designation D7689;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revi
2、sion.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope*1.1 This test method covers the determination of the cloudpoint of petroleum products,biodiesel,and biodiesel blendsthat are transparen
3、t in layers 40 mm in thickness,using anautomatic instrument.1.2 This test method covers the range of cloud pointtemperatures from 50 C to+6 C.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.4 This standard does not purport
4、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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 This international standard was dev
5、eloped in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Docume
6、nts2.1 ASTM Standards:2D2500 Test Method for Cloud Point of Petroleum Productsand Liquid FuelsD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD6708 Practice for Statistical Assessment and Improvementof Expec
7、ted Agreement Between Two Test Methods thatPurport to Measure the Same Property of a MaterialD6751 Specification for Biodiesel Fuel Blend Stock(B100)for Middle Distillate Fuels2.2 Energy Institute Standard:3IP219 Test Method for Cloud Point of Petroleum Products3.Terminology3.1 Definitions:3.1.1 bio
8、diesel,nfuel 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 of a vegetable oil or animal fat with an alcohol such asmethanol or ethanol in the presence of a catalyst to y
9、ieldmono-alkyl esters and glycerin,which is removed.The finishedbiodiesel derives approximately 10%of its mass from thereacted alcohol.The alcohol used in the reaction may or maynot come from renewable resources.3.1.2 biodiesel blend(BXX),na homogeneous mixture ofhydrocarbon oils and mono-alkyl este
10、rs of long chain fattyacids.3.1.2.1 DiscussionIn the abbreviation,BXX,the XX rep-resents the volume percentage of biodiesel fuel in the blend.3.1.2.2 DiscussionThe mono-alkyl esters of long chainfatty acids(that is,biodiesel)used in the mixture shall meet therequirements of Specification D6751.3.1.2
11、.3 DiscussionDiesel fuel,fuel oil,and non-aviationgas turbine oil are examples of hydrocarbon oils.3.1.3 biodiesel fuel,nsynonym for biodiesel.3.1.4 cloud point,nin petroleum products and biodieselfuels,the temperature of a liquid specimen when the smallestobservable cluster of wax crystals first oc
12、curs upon coolingunder prescribed conditions.3.1.4.1 DiscussionThe cloud point occurs when the tem-perature of the specimen is low enough to cause wax crystalsto precipitate.In a homogeneous liquid,the cloud is alwaysnoted first at the location in the specimen where the specimentemperature is the lo
13、west.The cloud point is the temperature at1This 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 Jan.1,2021.Published January 2021.Originally
14、approved in 2011.Last previous edition approved in 2020 as D7689 20.DOI:10.1520/D7689-21.2For 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 p
15、age onthe ASTM website.3Available from Energy Institute,61 New Cavendish St.,London,WIG 7AR,U.K.,http:/www.energyinst.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis
16、international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1which the crystals first occur,regardless of their location in thespecimen,and not after extensive crystallization has takenplace.The wax crystals that precipitate at lower temperaturesare t