Patent ID: 8907139

Claim:
A process for purifying a crude ethanol product, the process comprising the steps of: hydrogenating acetic acid in the presence of a catalyst in a reactor to form a crude ethanol product comprising ethanol, water, ethyl acetate and acetal; 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; feeding an acid stream to the first column to hydrolyze the acetal; removing water from at least a portion of the first distillate to yield an ethanol mixture stream comprising less than 10 wt. % water; and separating a portion of the ethanol mixture stream in a second distillation column to yield a second residue comprising ethanol and a second distillate comprising ethyl acetate.