Optimizing Acoustic Energy for Better Transesterification: A Novel Sono-Chemical Reactor Design

Sono-chemical conversion is a process intensification technique increasingly being applied to several reactions due to its characteristic ability to reduce process time and increase production. Its application to the transesterification reaction (vegetable oil to biodiesel) has been widely studied and it is proven to give better results. Although this provides an advantage in processing time, the production volumes are still limited due to the existing inefficient reactor designs which are mostly batch type. In this work, we design a novel continuous flow sonochemical reactor with the aim to have higher biodiesel production. The uniqueness in the design comes from the shape and the addition of a static mixer. The variations in design (i.e. inclusion and exclusion of static mixer) is studied through numerical simulation of the acoustic wave, cavitation bubble temperature, reactive flow and chemical kinetics in a 2D axi-symmetric model of the reactor. Acoustic pressure, cavitation bubble temperature and biodiesel concentration are studied. It is noticed that the static mixer, which is made of a sound reflecting material, provides several physical advantages which positively affect the biodiesel formation. Due to the static mixer the peak acoustic pressure was higher (1.93 MPa) and also more regions of the reactor experienced acoustic pressure exceeding the blake. This enhanced the cavitation bubble temperatures and the biodiesel mole fractions.