Influence of operating conditions and design parameters on hydrodynamics and mass transfer in an emulsion loop-venturi reactor

The aim of this paper is first to investigate the influence of operating conditions and design parameters on the hydrodynamics and the mass transfer properties of an emulsion loop-venturi reactor and then to compare its performance to that of the conventional gas-liquid contactors, such as airlift and bubble column reactors or aerated stirred tanks. The results have shown that emulsion venturi reactors should be preferentially operated as gas-inducing devices. In this case, hydrodynamics and mass transfer depend strongly on the clear liquid height. This parameter exhibits an optimum value, as its increase improves mass transfer, but reduces the maximum gas-induced flow rate. Conversely, the respective influences of the tank diameter at constant clear liquid height when D > 0.3 m and of the surface area of the orifices at the venturi throat were not significant in this work. Finally, emulsion loop-venturi contactors appear to be versatile tools able to carry out both fast and slow chemical reactions, which is not the case for the three other kinds of reactors. They are therefore useful when high and quickly adaptable oxygen supply is required, as they avoid also the presence of mechanically moving parts and present lower shear levels than mechanically stirred tanks. (c) 2006 Elsevier B.V. All rights reserved.