Experimental study on dealcoholization of wine by osmotic distillation process

Abstract

The types of stripping solutions and influences of operating parameters including feed and stripping velocities, system temperatures on the ethanol removal of ethanol solution and wine by using osmotic distillation (OD) process were investigated along with the mass transfer study. The experiments were performed by the membrane contactor unit using 0.2 μm pore size diameter microporous PVDF hollow fibers. Three different types of stripping solutions (pure water, 50% (w/w) glycerol, 40% (w/w) CaCl 2) were used to compare the dealcoholization performance of the process. Aroma loss study was also carried out by using ethyl acetate and iso-amyl alcohol solutions to represent the major aroma compounds presenting in the real wine. Long-term tests for ethanol solution and wine were also performed in order to evaluate the dealcoholization performance of OD process. Using water as a stripper presented more promising result compared with the others because it provided higher ethanol flux and lower counter transport of water due to the water activity differences. The results of the study showed that the ethanol flux and ethanol removal performance were enhanced by the increase of feed and stripping solution velocities and system temperatures. Aroma components were significantly lost during the process operation. The ethanol concentration in the wine can be reduced to roughly 34% of the initial concentration for 360 min operation.