HOW SLUG FLOW CAN ENHANCE THE ULTRAFILTRATION FLUX IN MINERAL TUBULARMEMBRANES

The study deals with the use of a gas-liquid two-phase flow to reduce tubular mineral membrane fouling by injecting air directly into the fe ed stream. The injected air is supposed to create complex hydrodynamic conditions inside the ultrafiltration module which destabilize the co ncentration layer over the membrane surface. The experimental study wa s carried out by filtering suspensions (bentonite and yeast) through a n ultrafiltration tubular mineral membrane. A range of transmembrane p ressures and various liquid and gas flow-rates were tested. Results re lated to the permeate flux showed an enhancement by a factor of 3, wit h a slug flow-structure for the two kinds of suspension (200% of flux increase). Furthermore, the applicability of such an unsteady techniqu e was examined with a view to reduce energy consumption.