Comparison of three different systems used for flux enhancement: application to crossflow filtration of yeast suspensions

The aim of this work is to characterize more accurately, through experimental or theoretical approaches, the hydrodynamics of three particular systems usually used for flux enhancement: shear-enhanced filtration with a vibrating membrane module, gas/liquid two-phase flows and Dean vortices. The correlation between local hydrodynamics and permeate flux obtained during crossflow filtration of a yeast suspension under different operating conditions confirmed the importance of the wall shear stress in these three systems.

Although the three systems were operated in different ranges of shear stress, our results confirmed the importance of the wall shear stress, which, together with yeast concentration, governed the permeate flux whatever the system studied. The permeate flux was directly correlated to a power of the membrane shear stress ranging from 0.43 to 0.87. However, for these systems in which radial distributions and time variations are important parameters, it will be further necessary to quantify their influence on flux improvement.