Experimental Parametric Analysis of Biodiesel Synthesis in Microreactors with Waste Cooking Oil

Abstract

This study investigates biodiesel synthesis with waste cooking oil using a microchannel device thermally driven using rejected heat through a parallel heat exchange process. Rather than use a resource-intensive full factorial experimental analysis, a partial factorial Taguchi analysis was used to explore parametric effects and greatly reduce the amount of experiments needed. The reduction of free fatty acids in vegetable oil was first studied. While free fatty acid content of the oil was reduced to 0.2%, below the recommended level for transesterification (0.5%), large amounts of emulsions were created during purification which makes the process less feasible for large scale production use. The parametric effects of transesterification were then investigated using purified waste cooking oil. A biodiesel conversion of 98% was achieved which is very close to the industrially acceptable level of conversion. In addition to the high level of conversion, the reaction time of the synthesis was only 2 minutes which is much lower than the reaction times using traditional batch reactors. The analysis suggested that the conversion could be increased with an increase in catalyst concentration.