Compendium of Experimental Cetane Numbers J. Yanowitz Ecoengineering M.A. Ratcliff, R.L. McCormick, and J.D. Taylor National Renewable Energy Laboratory M.J. Murphy Battelle Based on the Compendium of Experimental Cetane Numbers, NREL/TP-5400-61693, August 2014 NREL is a national laboratory of the U.S. Department of Energy Office of Energy Efficiency & Renewable Energy Operated by the Alliance for Sustainable Energy, LLC This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications. Technical Report NREL/TP-5400-67585 February 2017 Contract No. DE-AC36-08GO28308 Compendium of Experimental Cetane Numbers J. Yanowitz Ecoengineering M.A. Ratcliff, R.L. McCormick, and J.D. Taylor National Renewable Energy Laboratory M.J. Murphy Battelle Prepared under Task No. VTP2.9600 NREL is a national laboratory of the U.S. Department of Energy Office of Energy Efficiency & Renewable Energy Operated by the Alliance for Sustainable Energy, LLC This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications. National Renewable Energy Laboratory Technical Report 15013 Denver West Parkway NREL/TP-5400-67585 Golden, CO 80401 February 2017 303-275-3000 • www.nrel.gov Contract No. DE-AC36-08GO28308 NOTICE This report was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. 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Acknowledgments The authors would like to acknowledge the assistance of Jon Luecke and Lisa Fouts in using the ignition quality tester at the National Renewable Energy Laboratory and the assistance of Andre Boehman (Department of Mechanical Engineering, University of Michigan), Mac Haas (Department of Mechanical and Aerospace Engineering, Princeton University), Anthony Marchese (Department of Mechanical Engineering, Colorado State University), Jim Anderson, (Ford Motor Company) in locating cetane number data. Joshua D. Taylor is currently with SABIC, Sugarland, Texas. iii This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications. List of Acronyms ASTM ASTM International CAD crank angle degree CFR Cooperative Fuel Research CN cetane number CVCC constant-volume combustion chamber DCN derived cetane number FIT Fuel Ignition Tester HMN 2,2,4,4,6,8,8-heptamethylnonane IQT Ignition Quality Tester NREL National Renewable Energy Laboratory PRF primary reference fuel iv This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications. Executive Summary This report is an updated version of the 2014 Compendium of Experimental Cetane Number Data and presents a compilation of measured cetane numbers for pure chemical compounds. It includes all available single-compound cetane number data found in the scientific literature up until December 2016 as well as a number of previously unpublished values, most measured over the past decade at the National Renewable Energy Laboratory. This version of the compendium contains cetane values for 497 pure compounds, including 204 hydrocarbons and 293 oxygenates. One hundred seventy-five individual measurements are new to this version of the compendium, all of them collected using ASTM Method D6890, which utilizes an Ignition Quality Tester (IQT), a type of constant-volume combustion chamber. For many compounds, numerous measurements are included, often collected by different researchers using different methods. The text of this document is unchanged from the 2014 version, except for the numbers of compounds in Section 3.1; the appendices; Table 1, Primary Cetane Number Data Sources; and Table 2, Number of Measurements Included in Compendium. Cetane number is a relative ranking of a fuel’s autoignition characteristics for use in compression ignition engines. It is based on the amount of time between fuel injection and ignition, also known as ignition delay. The cetane number is typically measured either in a single-cylinder engine or a constant-volume combustion chamber. Values in the 2004 compendium derived from octane numbers have been removed and replaced with a brief analysis of the correlation between cetane numbers and octane numbers. The discussion on the accuracy and precision of the most commonly used methods for measuring cetane number has been expanded, and the data have been annotated extensively to provide additional information that will help the reader judge the relative reliability of individual results. v This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications. Table of Contents List of Acronyms ........................................................................................................................................ iv List of Figures ............................................................................................................................................ vi List of Tables .............................................................................................................................................. vi 1 Introduction ........................................................................................................................................... 1 2 Measuring Cetane Number .................................................................................................................. 3 2.1 Reference Fuels ............................................................................................................................. 3 2.2 Test Engine Configuration ............................................................................................................ 4 2.3 Constant-Volume Combustion Chamber ...................................................................................... 4 2.4 Blending Cetane Numbers ............................................................................................................ 6 3 Cetane Number Data Quality ............................................................................................................... 7 3.1 Origin of Data ................................................................................................................................ 7 3.2 Purity of Compounds .................................................................................................................... 9 3.3 Reference Compounds .................................................................................................................. 9 3.4 Low and High Cetane Number Fuels ............................................................................................ 9 3.5 Accuracy of Cetane Number Determinations ............................................................................. 10 3.6 Estimation Methods for Cetane Number ..................................................................................... 13 4 Summary ............................................................................................................................................. 14 Appendix A. Compendium of Experimental Cetane Number Data ...................................................... 15 Appendix B. Sources for Cetane Number Data...................................................................................... 63 References ................................................................................................................................................. 69 List of Figures Figure 1. Structure of 1-hexadecene (cetene or ketene) ................................................................................ 3 Figure 2. Structure of α-methylnaphthalene ................................................................................................. 3 Figure 3. Structure of n-hexadecane (cetane) ..............................................................................................