ASTM D976-04a
(Test Method)Standard Test Methods for Calculated Cetane Index of Distillate Fuels
Standard Test Methods for Calculated Cetane Index of Distillate Fuels
SCOPE
1.1 These test methods cover the Calculated Cetane Index formula, which represents a means for directly estimating the ASTM cetane number of distillate fuels from API gravity and mid-boiling point. The index value, as computed from the formula, is termed the Calculated Cetane Index.
1.2 The Calculated Cetane Index is not an optional method for expressing ASTM cetane number. It is a supplementary tool for predicting cetane number when used with due regard for its limitations.
1.3 The Calculated Cetane Index formula is particularly applicable to straight-run fuels, catalytically cracked stocks, and blends of the two.
Note 1—These test methods are temporarily retained because the proposal to the U.S. EPA to control diesel fuel aromatics concentrations via a 40 Calculated Cetane Index minimum is based on the correlation between Test Method D 976 and aromatics concentration. Test Method D 4737 is the preferred method as estimator of cetane number.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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An American National Standard
Designation:D976–04a
Standard Test Method for
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Calculated Cetane Index of Distillate Fuels
This standard is issued under the fixed designation D 976; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript 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* Petroleum Products (Hydrometer Method)
D 613 Test Method for Cetane Number of Diesel Fuel Oil
1.1 This test method covers the Calculated Cetane Index
D 1298 Test Method for Density, Relative Density (Specific
formula, which represents a means for directly estimating the
Gravity), or API Gravity of Crude Petroleum and Liquid
ASTM cetane number of distillate fuels from API gravity and
Petroleum Products by Hydrometer Method
mid-boiling point. The index value, as computed from the
2 D 4052 Test Method for Density and Relative Density of
formula, is termed the Calculated Cetane Index.
Liquids by Digital Density Meter
1.2 The Calculated Cetane Index is not an optional method
D 4737 Test Method for Calculated Cetane Index by Four
forexpressingASTMcetanenumber.Itisasupplementarytool
Variable Equation
for predicting cetane number when used with due regard for its
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2.2 ASTM Adjuncts:
limitations.
ADJ0976 Nomograph for Calculated Cetane Index
1.3 The Calculated Cetane Index formula is particularly
applicable to straight-run fuels, catalytically cracked stocks,
3. Significance and Use
and blends of the two.
3.1 The Calculated Cetane Index is a useful tool for esti-
NOTE 1—This test method is temporarily retained because the proposal
mating ASTM cetane number where a test engine is not
to the U.S. EPA to control diesel fuel aromatics concentrations via a 40
available for determining this property. It may be conveniently
Calculated Cetane Index minimum is based on the correlation between
employed for approximating cetane number where the quantity
Test Method D 976 and aromatics concentration. Test Method D 4737 is
of sample is too small for an engine rating. In cases where the
the preferred method as estimator of cetane number.
cetanenumberofafuelhasbeeninitiallyestablished,theindex
1.4 This standard does not purport to address all of the
is useful as a cetane number check on subsequent samples of
safety concerns, if any, associated with its use. It is the
that fuel, provided its source and mode of manufacture remain
responsibility of the user of this standard to establish appro-
unchanged.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
4. Equation for Calculated Cetane Index
4.1 The Calculated Cetane Index is determined from the
2. Referenced Documents
following equation:
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2.1 ASTM Standards:
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Calculated cetane index52420.34 1 0.016 G 1 0.192 G log M
D 86 Test Method for Distillation of Petroleum Products at
2 2
1 65.01 ~log M! 2 0.0001809 M (1)
Atmospheric Pressure
D 287 TestMethodforAPIGravityofCrudePetroleumand
or
2
Calculated cetane index 5 454.74 2 1641.416 D 1 774.74 D
2
20.554 B 1 97.803 log B (2)
~ !
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This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
where:
D02.E0 on Burner, Diesel, Non-Aviation Gas Turbine, and Marine Fuels.
G = API gravity, determined by Test Method D 287,
Current edition approved Aug. 1, 2004. Published August 2004. Originally
approved in 1966. Last previous edition approved in 2004 as D 976–04. D 1298, or D 4052,
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A method of calculating cetane index was developed by the Diesel Fuels
M = mid-boiling temperature, °F, determined by Test
Division, Coordinating Fuel and Equipment Research Committee of the Coordinat-
Method D 86 and corrected to standard barometric
ing Research Council. SeeYoung, H. D., “Methods for Estimating Cetane Number,”
pressure,
Proceedings, PPIRA, American Petroleum Institute, Vol. 30 M [III], 1950. This
method was revised in 1960 by Research Division I of Committee D02 to conform
to the revised Test Method D 613.
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For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
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Standards volume information, refer to the standard’s Document Summary page on Available from ASTM International Headquarters. Order Adjunct No.
the ASTM website. ADJD0976.
*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.
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D976–04a
5.1.
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