Wine clarification with rotating and vibrating filtration (RVF): investigation of the impact of membrane material, wine composition and operating conditions

For the first time in the literature, a shear enhanced process (or dynamic filtration) called Rotating and Vibrating Filtration (RVF technology) was investigated for wine clarification. The impact of membrane material (hydrophilic PES and hydrophobic PTFE with a cut-off of 0.2 mu m), wine composition (filtered wine, FW and Crude simulated wine, CSW) and operating conditions (transmembrane pressure and rotational frequency) are reported. RVF module is characterized by a complex hydrodynamic generated by a 3 flat blades impeller in a confined cell. An additional driving force is generated by rotational frequency and is taken into account to calculate the apparent and real permeabilities. Filtered wine (FW) generates an irreversible fouling whatever hydrophilic or hydrophobic membrane material. Even if PES membranes performances (Lp(0) (final)=1670 L h(-1) m(-2) bar(-1)) were higher compared to those of PTFE membranes (Lp(0 final)=170 L h(-1) m(-2) bar(-1)), nor rotational frequency (mechanical stress), nor water rinsing did significantly remove or reduce fouling but, on the contrary, favors its compression and membrane plugging. Crude simulated wine (CSW) includes pectins, tannins and mannoproteins. CSW filtration runs demonstrated a mechanical impact onto fouling reduction with PES and PTFE membranes. However mechanical efficiency is moderated by material properties which generated irreversible fouling with different magnitudes. PTFE and PES permeability gains stand for +34% and +300% respectively. Finally, a "critical frequency' is defined above which a permeability increase and hydraulic resistance reduction is induced by rotational frequency (22 and 30 Hz for PES and PTFE membranes respectively)