Numerical analysis of heat and mass transfer in microreactors for biodiesel synthesis

Abstract

The increasing global demand for sustainable energy sources has driven significant advancements in biodiesel production technologies. Microreactors have emerged as a promising alternative to conventional batch and continuous reactors due to their enhanced heat and mass transfer characteristics, as well as their potential for process intensification. This study presents a numerical investigation of the coupled flow, heat, and mass transfer phenomena in microreactors used for biodiesel synthesis, focusing on the impact of different geometrical configurations and the presence of obstacles within the reactor. The primary objective of this research is to evaluate the influence of microreactor design and thermal conditions on flow dynamics, and mixing efficiency, and reaction performance. The governing Navier-Stokes, energy, and species transport equations are discretized using the Galerkin Finite Element Method (FEM) combined with a Semi-Lagrangian advection scheme, ensuring a high-fidelity representation of the transport processes and chemical kinetics. Simulations are performed for various microreactor configurations, including designs with and without obstacles, across a range of Reynolds numbers and operating temperatures. Results indicate that the inclusion of obstacles enhances mixing by inducing chaotic advection and promoting interfacial interactions between reactants. Furthermore, the temperature field significantly influences both the local reaction rates and the overall conversion efficiency. The analysis also highlights the interplay between flow regime, heat transfer, and species conversion, which determines the stability and efficiency of the biodiesel synthesis process.