PROCESSO PER DISTILLARE E PURIFICAPRE UNA MISCELA GREZZA CONTENENTE ALCOOL

摘要

A crude alcohol-containing mixture comprising a saturated aliphatic alcohol of not more than three carbon atoms and associated impurities is processed in a three-tower distillation system to permit recovery of the desired alcohol product in highly concentrated and purified form. In the first tower the crude feed is subjected to extractive distillation with water to remove substantially all the impurities overhead. An aqueous bottoms stream from the first tower containing 5 to 10 wt.% alcohol and only minor amount of impurities is fed to the second tower where the alcohol product is concentrated and recovered. Overhead and intermediate purge streams containing low boiling and hgh boiling impurities are removed from the second tower and are fed to the third tower along with the overhead from the first tower. Stripped aqueous effluent is withdrawn from the bottom of the second tower and is recycled in part to the first tower. An aqueous alkali solution is introduced into the second tower and regulated so that the concentration of alkali in the stripped aqueous effluent from the bottom of the tower is from about 0.10 to about 0.24 gram per liter. The impurities are recovered as by-products from the third tower, and an alcohol stream is recycled from the third tower to the first tower.