Gas Transfer Management by Membrane Contactors in an Oenological Context: Influence of Operating Parameters and Membrane Materials

Oxygen management in wine is one of most challenging issue for winemakers. Indeed, an excess of dissolved oxygen (O-2) can prematurely age wine and leads to organoleptic deviation. Membrane contactors composed of hydrophobic hollow fiber are becoming a relevant technology especially for gas-liquid mass transfer operations. Nevertheless, their utilization in an oenological context to manage oxygen in wine has not been comprehensively studied. Fouling phenomena could be problematic and may limit their utilization during winemaking. The aim of this study is to develop (i) a simple and rapid method to characterize membrane contactors and (ii) to investigate the effects of two types of membrane contactor composed either of polypropylene (PP) or of PP with a dense coat layer (Teflon). The specific methodology proposed using volumetric transfer coefficient (K-L center dot A) is used to investigate the performance of the membranes on gas transfer in terms of wetting and fouling, as well as the effect of the membrane material. After liquid flow rate optimization, which was necessary to determine a suitable value (300 mL.min(-1)), the membrane contactors' performances were characterized with water, a wine model solution and two red wines with different fouling index. After several hydrodynamic optimization operations, we consider that the membrane contactors studied could remove oxygen while carbon dioxide is dissolved with KL center dot a(2)(CO) close to 20 x 10(-5) s(-1) for both prototypes. The addition of a dense coat layer in an oenological context may be necessary for a non-prepared wine with a high fouling index.