Biodiesel Production Via Hydrodynamic Cavitation: Numerical Study of New Geometrical Arrangements

Abstract

Hydrodynamic Cavitation is employed as process enhancer for the industrial production of biodiesel with important improvements in energy efficiency, yields and required time. These improvements can play an important role in the new generation of biodiesel facilities, even more under the recent global scenario of low petroleum prices where the biodiesel industry is struggling to be competitive and economically sustainable. In this framework the cost and time reduction can be achieved overcoming the present limitations of low mass transfer coefficients and enabling the utilization of high fatty acid oils. This work explores via an integrated mathematical model (computational fluid dynamics and single bubble dynamics) several geometrical possibilities for cavitational reactors with simple construction and easy scalability as cylinders and Venturi channel arrangements. The paper presents the fundamental equations and the global simulation criteria integrating the multi-scale approaches for the evaluation of cavitation activities and power consumption in transesterification reactors. The preliminary results are presented in this paper, together with an innovative overall comparison including the different features characterizing the cavitation performances. Finally, the methodology applied to 16 configurations of Venturi and cylinder arrangements suggest that the cylinder arrangement named 4510 (array cylinders with throat diameter of 4mm and cylinder diameter of 5mm) has better overall performance at less energy consumption, reaching up to 95% of active cavities and an average performance of 60% compared with other evaluated geometries.