Influence of Feedstock and Process Chemistry on Biodiesel Quality

Biodiesel production in the United States is anticipated to double by 2010. Biodiesel's characteristics and performance as a fuel vary depending on its composition, and the fuel composition has to be stringently monitored to avoid adverse impacts on the environment and engines. The final biodiesel composition depends on the initial feedstock, as well as on the reaction conversions and process separation efficiencies. The thermo-physical properties depend upon factors such as chain length, branching, and degree of saturation. Impurities in biodiesel, either due to side-reactions, unreacted feedstock, or non-fatty acid constituents, may increase pollutants. This paper focuses on chemical composition of commonly used feedstocks for biodiesel manufacturing and provides an overview of the process chemistry.