Combustion Chemistry of Biodiesel Fuels From a Wide Variety of Plant and Other Oils

Biofuels are attractive alternatives to the petroleum derived fuels typically used for transportation. Biodiesel is of particular interest since it can replace petroleum diesel in compression ignition engines. Chemical kinetic mechanisms are an important tool used by engine designers to better understand the fundamental combustion properties of biodiesel. This presentation covers recent advances and in the chemical kinetic modeling of biodiesel (i.e., fatty acid methyl esters) combustion. A detailed chemical kinetic reaction mechanism developed for the major components of soy and rapeseed oil methyl ester biodiesel fuels is used to simulate combustion of biodiesel fuels derived from other vegetable oils and animal fats. Variations in combustion properties of these different fuels are related to differences in the compositions of the fuels, all within the limits of all of the fuels being constituted from the same five basic methyl ester components. The primary factor determining differences in combustion properties is shown to be the number of C=C double bonds in some of these components.  We also show how mechanism reduction algorithms enable the utilization of biodiesel combustion mechanisms for high fidelity 3D-CFD simulations of practical combustion devices.

The portion of this work supported by LLNL Lawrence Livermore National Laboratory was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.