1、Designation: D 976 06An American National StandardStandard Test Method forCalculated Cetane Index of Distillate Fuels1This standard is issued under the fixed designation D 976; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the ye
2、ar 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.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This test method covers the C
3、alculated 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 met
4、hodfor 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.NOTE 1This test method is
5、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 D 976 and aromatics concentration. Test Method D 4737 isthe preferred method as estimator of cetane number.1
6、.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 Do
7、cuments2.1 ASTM Standards:3D86 Test Method for Distillation of Petroleum Products atAtmospheric PressureD 287 Test Method forAPI Gravity of Crude Petroleum andPetroleum Products (Hydrometer Method)D 613 Test Method for Cetane Number of Diesel Fuel OilD 1298 Test Method for Density, Relative Density
8、(SpecificGravity), or API Gravity of Crude Petroleum and LiquidPetroleum Products by Hydrometer MethodD 2887 Test Method for Boiling Range Distribution ofPetroleum Fractions by Gas ChromatographyD 4052 Test Method for Density and Relative Density ofLiquids by Digital Density MeterD 4737 Test Method
9、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 emplo
10、yed 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 remai
11、nunchanged.3.2 Test Method D 4737 may also be used to approximatethe ASTM cetane number of diesel fuels.3.2.1 Procedure A of Test Method D 4737 was developed asa result of a larger degree of offset between Test Method D 976Cetane Index and the results of Test Method D 613 over theentire range of the
12、 correlation. Generally, it has been found thatuse of Test Method D 4737 results in less offset than use of TestMethod D 976, but there can be specific cases where this is nottrue.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct
13、responsibility of SubcommitteeD02.E0.02 on Diesel Fuel Oils.Current edition approved Dec. 1, 2006. Published January 2007. Originallyapproved in 1966. Last previous edition approved in 2004 as D 97604be1.2A method of calculating cetane index was developed by the Diesel FuelsDivision, Coordinating Fu
14、el 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 T
15、est Method D 613.3For 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 Headquart
16、ers. Order Adjunct No.ADJD0976. Original adjunct produced in 1989.1*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.3.2.2 Procedure A of Test Method D 4737 is recommende
17、dto estimate the cetane number of diesel fuels with sulfurcontents above 500 ppm or No. 1D diesel fuels.3.2.3 Procedure B of Test Method D 4737 is recommendedto estimate the cetane number of No. 2D diesel fuels withsulfur contents at or below 500 ppm.3.3 Calculated Cetane Index, as described in Test
18、 MethodD 97680, is recognized by the United States EPA as analternative method to meet the U.S. Federal Diesel aromaticslimit for diesel fuels containing less than 500 ppm sulfur. Theequation for Calculated Cetane Index in Test Method D 97680and in this version (D 97606) of the test method are the s
19、ame.4. Equation for Calculated Cetane Index4.1 The Calculated Cetane Index is determined from thefollowing equation:Calculated cetane index 52420.34 1 0.016 G21 0.192 G log M1 65.01 log M!22 0.0001809 M2(1)orCalculated cetane index 5 454.74 2 1641.416 D 1 774.74 D220.554 B 1 97.803 log B!2(2)where:G
20、 = API gravity, determined by Test Method D 287,D 1298,orD 4052,M = mid-boiling temperature, F, determined by TestMethod D86 and corrected to standard barometricpressure,D = density at 15C, g/mL, determined by Test MethodD 1298 or D 4052, andB = mid-boiling temperature, C, determined by TestMethod D
21、86 and corrected to standard barometricpressure.4.2 Calculated Cetane Index values for distillate fuels maybe conveniently determined by means of the alignment chart inFig. 1 rather than by direct application of the equation. Use ofthe chart is illustrated by the example shown on the chart.4.3 Test
22、Method D 2887 may be used as an alternative toTest Method D86to determine the mid-boiling temperature ofthe fuel.4.3.1 If Test Method D 2887 is used, convert the data toestimated Test Method D86 data following Appendix X5,Correlation of Jet and Diesel Fuel of test Method D 2887 anduse the data from
23、Test Method D86in place of the actual TestMethod D86data in the calculations.NOTE 2Current U.S. EPA regulations for low sulfur (500 ppmmaximum) No. 1D and No. 2D diesel fuel require the use of TestMethod D 97680 to calculate Cetane Index.5. Limitations of Equation5.1 The Calculated Cetane Index equa
24、tion possesses certaininherent limitations which must be recognized in its applica-tion. These are:5.1.1 It is not applicable to fuels containing additives forraising cetane number.5.1.2 It is not applicable to pure hydrocarbons, syntheticfuels, such as certain products derived from shale oils and t
25、arsands, alkylates, or coal-tar products.5.1.3 Substantial inaccuracies in correlation may occur ifused for crude oils, residuals, or products having a volatility ofbelow 500F end point.6. Report6.1 Round and report the calculated cetane index to thenearest tenth. Any calculated cetane index value e
26、nding inexactly “5” in the second decimal place shall be rounded to thenearest even tenth number. For example, round “35.55” and“35.65” to “35.6 cetane index.”7. Precision and Bias7.1 Correlation of index values with ASTM cetane numberis dependent to a great extent upon the accuracy of determi-natio
27、n of both API gravity and midboiling point.7.2 Within the range from 30 to 60 cetane number, theexpected correlation of the Calculated Cetane Index with theASTM cetane number will be somewhat less than 62 cetanenumbers for 75 % of the distillate fuels evaluated. Errors incorrelation may be greater f
28、or fuels whose cetane numbers areoutside this range. Correlation is best for straight-run andcatalytically cracked distillates and blends of the two, and leastsatisfactory for blends containing substantial proportions ofthermally cracked stocks.8. Keywords8.1 cetane; cetane index; diesel fuelD976062
29、NOTEThe Calculated Cetane Index equation represents a useful tool for estimating cetane number. Due to inherent limitations in the equationsapplication, Index values may not be a valid substitute for ASTM cetane numbers as determined in a test engine.FIG. 1 Nomograph for Calculated Cetane Index (ECS
30、-1 Meter BasisTest Method D 613)D976063SUMMARY OF CHANGESSubcommittee D02.E0 has identified the location of selected changes to this standard since the last issue(D 97604be1) that may impact the use of this standard.(1) Revised 1.2.(2) Revised 3.1.(3) Added 3.2-3.3.ASTM International takes no positi
31、on respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility
32、.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM
33、International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address sh
34、own below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D976064
