Process for producing ethanol and reducing acetic acid concentration

摘要

A process for producing ethanol and, in particular, to a process for reducing the concentration of acetic acid in a crude ethanol product by esterifying unreacted acetic acid with an alcohol.

主权项

1. A process for producing ethanol, comprising:
hydrogenating acetic acid and/or an ester thereof in a reactor in the presence of a catalyst to form a crude ethanol product; separating a portion of the crude ethanol product in a first distillation column to yield a first distillate comprising acetaldehyde and ethyl acetate, and a first residue comprising ethanol, acetic acid, and water; separating a portion of the first residue in a second distillation column to yield a second residue comprising acetic acid and water and a second distillate comprising ethanol; reacting the acetic acid from a first portion of the second residue with at least one alcohol in an esterification unit to produce at least one ester product stream, and a water stream that is substantially free of acetic acid; and recovering ethanol from the second distillate.