Investigation of Liquid-liquid Two Phase Flow in Biodiesel Production

Over the past two years the Australian biodiesel industry has faced difficult times causing large scale producers to drastically curtail production with some even ceasing operation. This turn of events has highlighted the advantages of small scale production, which are investigated in depth in a companion paper (de Boer and Bahri 2009a). For small scale production to be viable the transesterification reactor at the heart of the process must provide high conversion levels in short time periods. Assessing the performance of a particular reactor design is difficult due to the complex liquid-liquid reaction mixture that is affected by mass transfer, reaction kinetics and component solubility. This paper presents the first step in the development of a CFD model in ANSYS CFX that encapsulates the liquid-liquid flow phenomena observed in the reaction medium. The paper includes an analysis of the reaction mixture focusing on necessary simplifying assumptions, experimental flow visualisation results and an investigation of different simulation settings.