Review of Gas Holdup Characteristics of Bubble Column Reactors

Abstract

Gas-liquid bubble columns are used extensively in the process industries. The gas-liquid two phase flow prevailing in this type of process equipment is extremely complex, inherently unsteady and dominated by phenomena with widely varying time-and length-scales. It is for this reason that many important fluid dynamical aspects of gas-liquid bubble columns are still poorly understood and difficult to predict a priori. This paper aims to contribute to our understanding of the gas holdup characteristics of gas-liquid bubble column reactors by reviewing recently published studies. Three-phase bubble column reactors are widely employed in reaction engineering, i.e. in the presence of a catalyst and in biochemical applications where microorganisms are utilized as solid suspensions in order to manufacture industrially valuable bioproducts. Investigation of design parameters characterizing the operation and transport phenomena of bubble columns have led to better understanding of the hydrodynamic properties, heat and mass transfer mechanisms and flow regime characteristics ongoing during the operation. Moreover, experimental studies are supported with computational fluid dynamics (CFDs) simulations and developed mathematical models to describe better the phenomena taking place in a bubble column reactor. This review focuses on bubble column reactors, their description, design and operation, application areas, fluid dynamics and regime analysis encountered and parameters characterizing the operation are presented together with the findings of published studies. This work is the extension of work done by Kuntlu O Ulgen et al.,(2005).