Transesterification of soybean oil in four-way micromixers for biodiesel production using a cosolvent

In this work, transformation of soybean oil into fatty acid methyl ester (FAME) was studied in different four-way micromixers. Hexane was added to the reaction system as a cosolvent for mass transfer intensification. A three-level-five-factorial Central Composite Design using Response Surface Methodology was employed to optimize the reaction conditions. The main factors affecting the FAME content (wt.%) i.e. reaction temperature, residence time, hexane to methanol volumetric ratio, oil to methanol volumetric ratio and mixer configuration were discussed. The optimum combinations for transesterification to achieve a predicted maximum FAME of 97.67% were found. At this optimum condition, the observed FAME content was found to be 98.8%. The closeness of the experimental results and predicted values demonstrated that the regression model is significant. In the present work, residence time was reduced in an order of seconds (3-15 s), which it has not been fulfilled in the previous works. (C) 2016 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.