Between the bio-fuels used for autovehicles, bio-ethanol has an important role, due to the advantages it presents, having a good efficiency and a level of emissions released in the environment much lower than the conventional fuels. As bio-ethanol is obtained through the fermentation process of agricultural feedstock, these must be separated and concentrated. This can be obtained in more ways, we propose in this paper using of semi permeable membranes for separation in so-called process membrane distillation or prevaporation.