Synthesis, droplet combustion, and sooting characteristics of biodiesel produced from waste vegetable oils

In light of the potential of fatty acid methyl ester (FAME, i.e. biodiesel) as a renewable energy source, an innovative acid catalyzed process was developed for the synthesis of biodiesel from waste vegetable oils. The synthesized biodiesels were analytically characterized for their major components, molar fraction and molecular weight of each component, the average molecular weight, and the heat of combustion. Their droplet combustion characteristics in terms of the burning rate, flame size, and sooting tendency were subsequently determined in a high-temperature, freely-falling droplet apparatus. Results show that the biodiesel droplet has higher burning rate, and that biodiesel in general has a lower propensity to soot because its molecular oxygen content promotes the oxidation of the soot precursors.