1、Designation: D 4737 04An American National StandardStandard Test Method forCalculated Cetane Index by Four Variable Equation1This standard is issued under the fixed designation D 4737; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision
2、, 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.1. Scope1.1 The calculated Cetane Index by Four Variable Equationprovides a means for estimating the ASTM cetane nu
3、mber(Test Method D 613) of distillate fuels from density anddistillation recovery temperature measurements. The valuecomputed from the equation is termed the Calculated CetaneIndex by Four Variable Equation.1.2 The Calculated Cetane Index by Four Variable Equationis not an optional method for expres
4、singASTM cetane number.It is a supplementary tool for estimating cetane number whena result by Test Method D 613 is not available and if cetaneimprover is not used. As a supplementary tool, the CalculatedCetane Index by Four Variable equation must be used with dueregard for its limitations.1.3 Proce
5、dure A is to be used for Specification D 975,Grades No. 1D Low Sulfur, No. 1D, No. 2D, and No. 4D.This method for estimating cetane number was developed byChevron Research Co.2Procedure A is based on a data setincluding a relatively small number of No. 1D fuels. TestMethod D 4737 may be less applica
6、ble to No.1D, No. 1DLow Sulfur and No. 4D grades than to No. 2D grade.1.4 Procedure B is to be used for Specification D 975, GradeNo. 2D Low Sulfur.1.5 The test method “Calculated Cetane Index by FourVariable Equation” is particularly applicable to Grade 1-D,Grade No. 1D Low Sulfur and Grade 2-D die
7、sel fuel oilscontaining straight-run and cracked stocks, and their blends. Itcan also be used for heavier fuels with 90 % recovery pointsless than 382C and for fuels containing derivatives from oilsands and oil shale.1.6 The values stated in SI units are to be regarded as thestandard. The values giv
8、en in parentheses are for informationonly.1.7 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 regulator
9、y limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3D86 Test Method for Distillation of Petroleum ProductsD 613 Test Method for Cetane Number of Diesel Fuel OilD 975 Specification for Diesel Fuel OilsD 1298 Test Method for Density, Relative Density (SpecificGravity), or API Gravity
10、 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 Meter3. Summary of Test Method3.1 Two correlations in SI
11、units have been establishedbetween the ASTM cetane number and the density and 10 %,50 %, and 90 % distillation recovery temperatures of the fuel.Procedure A has been developed for diesel fuels meeting therequirements of Specification D 975 Grades 1-D Low Sulfur,Nos. 1-D, 2-D, and 4-D. The relationsh
12、ip is given by thefollowing equation.CCI 5 45.2 1 0.0892! T10N! 1 0.131 1 0.901!B!#T50N# (1)1 0.0523 2 0.420!B!#T90N# (1)1 0.00049T10N!22 T90N!2# (1)1 107!B! 1 60!B!2(1)where:CCI = Calculated Cetane Index by Four Variable Equa-tion,D = Density at 15C, g/mL determined by Test Meth-ods D 1298 or D 405
13、2,DN = D - 0.85,B =e(-3.5)(DN)-1,1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.E0 on Burner, Diesel, Non-Aviation Gas Turbine, and Marine Fuels.Current edition approved Dec. 1, 2004. Published
14、 December 2004. Originallyapproved in 1987. Last previous edition approved in 2003 as D 4737 03.2Ingham, M. C., et al., “Improved Predictive Equations for Cetane Number,”SAE Paper No 860250, Society of Automotive Engineers (SAE), 400 Common-wealth Dr., Warrendale, PA 15096-0001.3For referenced ASTM
15、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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohock
16、en, PA 19428-2959, United States.T10= 10 % recovery temperature, C, determined byTest Method D86and corrected to standard baro-metric pressure,T10N=T10- 215,T50= 50 % recovery temperature, C, determined byTest Method D86and corrected to standard baro-metric pressure,T50N=T50- 260,T90= 90 % recovery
17、temperature, C, determined byTest Method D86and corrected to standard baro-metric pressure, andT90N=T90- 310.3.2 The empirical equation for Procedure A of the Calcu-lated Cetane Index by Four Variable Equation was derivedusing a generalized least squares fitting technique whichaccounted for measurem
18、ent errors in the independent variables(fuel properties) as well as in the dependent variable (cetanenumber by Test Method D 613). The data base consisted of1229 fuels including; commercial diesel fuels, refinery blend-ing components and fuels derived from oil sands, shale, andcoal. The analysis als
19、o accounted for bias amongst the indi-vidual sets of data comprising the database.3.3 Procedure B has been developed for diesel fuels meetingthe requirements of Specification D 975 Grade 2-D LowSulfur. The relationship is given by the following equation:CCI 52386.26D! 1 0.1740 T10! 1 0.1215 T50! 1 0
20、.01850 T90!1 297.42 (2)where:CCI = Calculated Cetane Index by Four Variable EquationD = Density at 15C, g/mL determined by Test MethodsD 1298 or D 4052T10= 10 % recovery temperature, C, determined by TestMethod D86and corrected to standard barometricpressureT50= 50 % recovery temperature, C, determi
21、ned by TestMethod D86and corrected to standard barometricpressureT90= 90 % recovery temperature, C, determined by TestMethod D86and corrected to standard barometricpressure3.3.1 The equation for Procedure B when T10,T50, and T90are in F is:CCI 52386.26D! 1 0.09668 T10! 1 0.06751 T50! 1 0.01028 T90!1
22、 291.83 (3)where:CCI = Calculated Cetane Index by Four Variable EquationD = Density at 15C, g/mL determined by Test MethodD 1298 or D 4052T10= 10 % recovery temperature, F, determined by TestMethod D86and corrected to standard barometricpressureT50= 50 % recovery temperature, F, determined by TestMe
23、thod D86and corrected to standard barometricpressureT90= 90 % recovery temperature, F, determined by TestMethod D86and corrected to standard barometricpressure3.4 The empirical equation for Procedure B of the Calcu-lated Cetane Index by Four Variable Equation was derivedfrom National Exchange Group
24、data for 87 No. 2 Low Sulfurdiesel fuels with sulfur level between 16 and 500 ppm using aPartial Least Squares technique. A 2-principal componentmodel was chosen. The model was validated with a set of 980diesel fuels with sulfur levels in the same range.4. Significance and Use4.1 The Calculated Ceta
25、ne Index by Four Variable Equationis useful for estimating ASTM cetane number when a testengine is not available for determining this property directlyand when cetane improver is not used. It may be convenientlyemployed for estimating cetane number when the quantity ofsample available is too small f
26、or an engine rating. In caseswhere the ASTM cetane number of a fuel has been previouslyestablished, the Calculated Cetane Index by Four VariableEquation is useful as a cetane number check on subsequentbatches of that fuel, provided the fuels source and mode ofmanufacture remain unchanged.4.2 Within
27、the range from 32.5 to 56.5 cetane number, theexpected error of prediction of Procedure A of the CalculatedCetane Index by Four Variable Equation will be less than 62cetane numbers for 65 % of the distillate fuels evaluated.Errors may be greater for fuels whose properties fall outsidethe recommended
28、 range of application.5. Procedure5.1 Determine the density of the fuel at 15C to the nearest0.0001 g/mL, as described in Test Method D 1298 or TestMethod D 4052.5.2 Determine the 10 %, 50 %, and 90 % recovery tempera-tures of the fuel to the nearest 1C, as described in Test MethodD86.5.3 Test Metho
29、d D 2887 maybe used as an alternative toTest Method D86to determine the 10%, 50%, 90% recoverytemperatures of the fuel.5.3.1 If Test Method D 2887 is used, convert the TestMethod D 2887 data to estimated Test Method D86 datafollowing Appendix X5, Correlation of Jet and Diesel Fuel, ofTest Method D 2
30、887 and use the estimated Test Method D86data in place of actual Test Method D86data in the calcula-tions.5.3.2 Provision for use of test Method of D 2887 data in thisTest Method is intended to facilitate its use in determiningcompliance with Specification D 975 requirements. If this testmethod is u
31、sed for purposes other than Specification D 975compliance, the use of estimated Test Method D86data shouldbe reviewed to ensure it is acceptable.6. Calculation or Interpretation of Results6.1 Compute the Calculated Cetane Index by Four VariableEquation using the equation given in 3.1 (Procedure A) f
32、orGrades 1-D Low Sulfur, 1-D, 2-D, and 4-D. The calculation ofProcedure A is more easily performed using a computer orprogrammable hand calculator. Round the value obtained to thenearest one-tenth. Compute the Calculated Cetane Index byFour Variable Equation using the equation given in 3.3.(Procedur
33、e B) for Grade 2-D Low Sulfur.D47370426.1.1 Calculated Cetane Index by Four Variable Equation(Procedure A) can also be easily determined by means of thenomographs (applicable to Procedure A only) appearing inFigs. 1-3. Fig. 1 is used to estimate the cetane number of a fuelbased on its density at 15C
34、 and its 50 % recovery temperature.Fig. 2 is used to determine a correction for the estimate fromFig. 1 to account for deviations in the density and the 90 %recovery temperature of the fuel from average values. Fig. 3 isused to determine a second correction for the estimate fromFig. 1 to account for
35、 deviations in the 10 % and the 90 %recovery temperatures of the fuel from average values. Thecorrections determined from Fig. 2 and Fig. 3 are summedalgebraically with the cetane number estimate from Fig. 1 tofind the Calculated Cetane Index by Four Variable Equation(Procedure A). The method of usi
36、ng these nomographs isindicated by the illustrative example shown below and on Figs.1-3.Measured Fuel PropertiesTest Method D 613 Cetane Number 37.0Test Method D 1298 Density at 15C, kg/L 0.885Test Method D8610 % Recovery Temperature, C 234Test Method D8650 % Recovery Temperature, C 274Test Method D
37、8690 % Recovery Temperature, C 323Calculated Cetane IndexEstimate from Fig. 1 34.0Correction from Fig. 2 +0.6Correction from Fig. 3 +2.5_CCI = 37.16.2 The Calculated Cetane Index by Four Variable Equationpossesses certain inherent limitations which must be recog-nized in its application. These are a
38、s follows:6.2.1 It is not applicable to fuels containing additives forraising the cetane number.6.2.2 It is not applicable to pure hydrocarbons, nor tonon-petroleum fuels derived from coal.6.2.3 Substantial inaccuracies in correlation may occur ifthe equation is applied to residual fuels or crude oi
39、ls.FIG. 1 Calculated Cetane IndexFIG. 2 Calculated Cetane IndexFIG. 3 Calculated Cetane IndexD47370437. Report7.1 Report the result of Procedure A or Procedure B to onedecimal place (XX.X) as:Cetane Index by D 4737 Procedure A or B!5_(4)8. Precision and Bias8.1 The determination of Calculated Cetane
40、 Index by FourVariable Equation from measured density at 15C and mea-sured 10 %, 50 % and 90 % recovery temperatures is exact.8.2 PrecisionThe precision of the Calculated Cetane In-dex by Four Variable Equation is dependent on the precision ofthe original density and recovery temperature determinati
41、onswhich enter into the calculation. Test Method D 1298 has astated repeatability limit of 0.0006 kg/L and a stated reproduc-ibility limit of 0.0015 kg/L at 15C. Test Method D 4052 has astated repeatability of 0.0001 g/mL and reproducibility of0.0005 g/mL. Test Method D86has stated repeatability and
42、reproducibility limits which vary with the rate of change ofrecovery temperature. See Figs. 2 through 7 and Tables 7through 10 of Test Method D86for details.8.3 BiasNo general statement is made on bias of this testmethod since a comparison with accepted reference values isnot available.9. Keywords9.
43、1 cetane; cetane index; diesel fuelASTM International takes no position 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 risk
44、of infringement of such rights, are entirely their own responsibility.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
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46、our views known to the ASTM Committee on Standards, at the address shown 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).D4737044
