Determination On CFD Modeling For Bubble Column Reactor To Improve Biodiesel Fuel Production

Abstract

Superheated methanol vapor bubble method has been developed to produce biodiesel fuel (fatty acids methyl esters; FAME) without using any catalysts at atmospheric pressure. This non: catalytic trans-esterification has an advantage over other trans-esterification methods at cost for production of biodiesel fuel. However, reaction rate is still lower than that of conventional alkaline catalytic method. Contact surface between the methanol bubble and the oil acts as the limiting factor for enhancing the reaction rate. Therefore, this study will be devoted to the analysis of the bubble size distribution during the process in the reactor using the Computational Fluid Dynamics (CFD) method. The aim of this report was to obtain optimum modeling of CFD to describe the bubble distribution in superheated methanol vapor bubble column reactor. Two dimensional (2D) and three dimensional (3D) models were used in this CFD simulation. Two types of wall function model were also accounted to characterize the high velocity and coalescence or breakup of bubble in the liquid. The relationship of intake gas velocity/coalescence and gas holdup/contact surface area was studied not only by computationally, but also by experimentally. As the results, the gas holdup and contact surface area in bubble column reactor became larger significantly when intake gas velocity was increased. 3D-turbulent and non-equilibrium wall function model showed best results in CFD simulation. This CFD modeling will be useful to improve the design the bubble column reactor.