The chemical reaction of biodiesel in combustion is more complex than traditional hydrocarbon fuels because of the existence of saturated and unsaturated fatty acid methyl or ethyl esters. In this study, a series of molecular dynamics simulation with reactive force field is performed to investigate the combustion and pyrolysis of the extensively tested biodiesel surrogate fuel, i.e., methyl butanoate. By analyzing the time dependence and spatial distribution of intermediates and stable products, the chemical reaction mechanism is elucidated. The formation of nitrogen oxides during methyl butanoate combustion under fuel-air conditions is studied for the first time by reactive force field. In the pyrolysis simulation of pure methyl butanoate, the performance of CHO-2008 and CHO-2016 is tested in terms of the transferability and capability. The reactive molecular dynamics can be employed as an effective method for chemical reaction modelling of biodiesel combustion both qualitatively and quantitatively.
Keywords biodiesel, ReaxFF, molecular dynamics, pyrolysis, combustion