The objective of this work is to study the esterification of FFA present in low grade feedstock with crude glycerol, which is a by-product of biodiesel synthesis. Such reaction generates monoglyceride, which can be used in the manufacturing of biodiesel. This will improve the economics of biodiesel production through utilisation of the glycerol as a low value side product in the manufacturing of biodiesel and the use of low grade feedstock.
Kinetic study of the esterification process was performed using oleic acid (FFA) and USP grade glycerol. The optimum reaction conditions were found to be 220°C, 600rpm agitation speed and 1:6 molar ratio of oleic acid to glycerol, with a highest conversion of oleic acid of 99.7%. The reaction was found to be an irreversible second-order. Esterification of oleic acid with crude glycerol obtained from biodiesel synthesis obtained monoglyceride yield of 49.7% with oleic acid conversion of 62.9%. In addition, glycerolysis of beef tallow containing oleic acid was carried out giving monoglyceride yield of 56.1% and only small amounts of triglycerides.
The outcome of this investigation is very promising indicating that such approach can be adapted to lower biodiesel production cost.
Keywords: Biodiesel, esterification reaction, kinetics, monoglyceride, oleic acid and glycerol.