A detailed chemical kinetic mechanism has been developed for methyl decanoate, a large methyl ester. It can be used as a surrogate for the large methyl esters present in rapeseed and soybean derived biodiesel. This model has been built by following the rules established by Curran et al. for the oxidation of n-heptane, and it includes all the reactions known to be pertinent to both low and high temperatures. Computed results using the mechanism have been compared with methyl decanoate experiments in a CFR motored engine and oxidation of rapeseed oil methyl esters in a jet stirred reactor (JSR). In the CFR engine, the equivalence ratio was 0.25 with compression ratios of 4.4 to 5.6. In the JSR, validations were performed at 10 atm, temperatures from 800-1250 K, and equivalence ratios of 0.5 and 1.0 with a N2 mole fraction of 0.975 and .987, respectively. An important feature of this mechanism is its ability to reproduce the early formation of carbon dioxide that is unique to biofuels and due to the presence of the ester group in the reactant. The model also predicts ignition delay times and OH profiles very close to observed values in shock tube experiments fueled by n-decane. The model indicates that early CO2 production from biodiesel fuels can only be predicted by a detailed kinetic mechanism for a true methyl ester fuel. The present methyl decanoate mechanism provides a realistic kinetic tool for simulation of biodiesel fuels.

Download files (CHEMKIN format):

References

Herbinet, O., W. J. Pitz, and C. K. Westbrook, "Detailed Chemical Kinetic Oxidation Mechanism for a Biodiesel Surrogate," Combust. Flame 154 507-528 (2008). http://dx.doi.org/10.1016/j.combustflame.2008.03.003 UCRL-JRNL-234862.