LAUSR

Abstract Biodiesel synthesis can be performed in microreactors. These microdevices provide advantages for this process, since it can be conducted continuously at high conversion rates due to increased mixing and mass transfer. In this context, numerical simulations play a key role to take this technology to mass production. This study aims to address biodiesel synthesis, via transesterification of sunflower oil with ethanol and alkaline catalyst, in a structured microreactor. We applied a volume-of-fluid based model, implemented in OpenFOAM, in order to simulate mixing and reaction. We tested mixing of fluids for a range of Reynolds numbers, and we applied a Box-Behnken experimental design to investigate temperature, ethanol/oil molar ratio and catalyst concentration effects on oil conversion. Numerical results accurately predicted the highest oil conversion condition in comparison with experimental studies. We noticed a maximum oil conversion of 97.25% at 50 °C, 9:1 ethanol/oil molar ratio and 1.00% catalyst mass concentration, for a residence time of 12 s. Furthermore, the model proved to be more effective than others available in commercial software were. The computational tool developed in this study can be used by researchers and engineers involved in chemical processes, with emphasis on the area of continuous biodiesel production, both for the dimensioning of new reactors, and for understanding the dynamics of the process in existing reactors. Although this tool was developed in the context of microreactors, it could be applied to any reactor in continuous operation.