Process for removing water from alcohol mixtures

摘要

A process for removing water from an alcohol mixture, such as an ethanol mixture in the production of ethanol by hydrogenating acetic acid. The water is removed from a distillate of a first column using an adsorption unit, membrane, extractive column distillation, or a combination thereof.

主权项

1. A process for producing ethanol, comprising:
hydrogenating acetic acid in a reactor in the presence of a catalyst to form a crude ethanol product comprising ethanol, ethyl acetate, water, and acetic acid; separating at least a portion of the crude ethanol product in a first distillation column to yield a first residue comprising acetic acid and a first distillate comprising ethanol, ethyl acetate, and water; splitting the first distillate into a main stream and a bypass stream; removing water from at least a portion of the main stream to yield an ethanol mixture stream comprising less than 10 wt. % water; and feeding the ethanol mixture stream and at least a portion of the bypass stream to a second distillation column, wherein the water concentration of the feed to the second distillation column is from 0.5 wt. % to 15 wt. %.