2.2.4. Distillation
In order to produce fuel ethanol, wine must be purified to at least 95 1GL; centrifuged wine is purified in the distillation and rectification columns, producing hydrous (around93wt%) ethanol. In Brazil, the most common configuration of the distillation columns is illustrated in Fig. 3. Wine is fed at the top of column A1, located between columns D and A. At the top of column D, volatile compounds are removed, while vinasse which contains mostly water is obtained at the bottom of column A.Ethanol-richstreams (phlegms) containing around 50wt% ethanol are obtained at columns D and A.This first set of columns is called distillation.The second set, comprised by columns Band B1, is named rectification. Phlegms are fed to these columns, and the rest of the water is removed at the bottom of column B1, while hydrated ethanol is produced at the top of column B.