ASTM_D_976_-_06_2016.pdf

Designation:D97606(Reapproved 2016)Standard Test Method forCalculated Cetane Index of Distillate Fuels1This standard is issued under the fixed designation D976;the number immediately following the designation indicates the year oforiginal adoption or,in the case 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.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 This test method covers the Calculated Cetane Indexformula,which represents a means for directly estimating theASTM cetane number of distillate fuels from API gravity andmid-boiling point.The index value,as computed from theformula,is termed the Calculated Cetane Index.21.2 The Calculated Cetane Index is not an optional methodfor expressingASTM cetane number.It is a supplementary toolto estimate cetane number when used with due regard for itslimitations.1.3 The Calculated Cetane Index formula is particularlyapplicable to straight-run fuels,catalytically cracked stocks,and blends of the two.NOTE1This test method is temporarily retained because the proposalto the U.S.EPA to control diesel fuel aromatics concentrations via a 40Calculated Cetane Index minimum is based on the correlation betweenTest Method D976 and aromatics concentration.Test Method D4737 is thepreferred method as estimator of cetane number.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 limitations prior to use.2.Referenced Documents2.1 ASTM Standards:3D86 Test Method for Distillation of Petroleum Products andLiquid Fuels at Atmospheric PressureD287 Test Method for API Gravity of Crude Petroleum andPetroleum Products(Hydrometer Method)D613 Test Method for Cetane Number of Diesel Fuel OilD1298 Test Method for Density,Relative Density,or APIGravity of Crude Petroleum and Liquid Petroleum Prod-ucts by Hydrometer MethodD2887 Test Method for Boiling Range Distribution of Pe-troleum Fractions by Gas ChromatographyD4052 Test Method for Density,Relative Density,and APIGravity of Liquids by Digital Density MeterD4737 Test Method for Calculated Cetane Index by FourVariable Equation2.2 ASTM Adjuncts:4Nomograph for Calculated Cetane Index3.Significance and Use3.1 The Calculated Cetane Index is one tool available forestimating ASTM cetane number where a test engine is notavailable for determining this property.It may be employed forapproximating cetane number where the quantity of sample istoo small for an engine rating.In cases where the cetanenumber of a fuel has been initially established,the index isuseful as a cetane number check on subsequent samples of thatfuel,provided its source and mode of manufacture remainunchanged.3.2 Test Method D4737 may also be used to approximatethe ASTM cetane number of diesel fuels.3.2.1 Procedure A of Test Method D4737 was developed asa result of a larger degree of offset between Test Method D976Cetane Index and the results of Test Method D613 over theentire range of the correlation.Generally,it has been found thatuse of Test Method D4737 results in less offset than use of TestMethod D976,but there can be specific cases where this is nottrue.3.2.2 Procedure A of Test Method D4737 is recommendedto estimate the cetane number of diesel fuels with sulfurcontents above 500 ppm or No.1D diesel fuels.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direct responsibility ofSubcommittee D02.E0 on Burner,Diesel,Non-Aviation Gas Turbine,and MarineFuels.Current edition approved April 1,2016.Published May 2016.Originallyapproved in 1966.Last previous edition approved in 2011 as D976 06(2011).DOI:10.1520/D0976-06R16.2A method of calculating cetane index was developed by the Diesel FuelsDivision,Coordinating Fuel and Equipment Research Committee of the Coordinat-ing Research Council.See Young,H.D.,“Methods for Estimating Cetane Number,”Proceedings,PPIRA,American Petroleum Institute,Vol.30 M III,1950.Thismethod was revised in 1960 by Research Division I of Committee D02 to conformto the revised Test Method D613.3For 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.4Available from ASTM International Headquarters.Order Adjunct No.ADJD0976.Original adjunct produced in 1989.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.2.3 Procedure B of Test Method D4737 is recommendedto estimate the cetane number of No.2D diesel fuels withsulfur contents at or below 500 ppm.3.3 Calculated Cetan