Patent ID: 8506766

Claim:
A method for recovering acetic acid from an aqueous solution thereof, comprising: feeding into a liquid-liquid extraction column a plurality of aqueous liquid input feed streams of different acetic acid concentrations at different locations of the liquid-liquid extraction column based on feed stream acetic acid concentration, including in the liquid-liquid extraction column a guard bed near the top thereof containing a catalyst for esterification of alcohol by reaction with acetic acid to form a corresponding ester, feeding into the liquid-liquid extraction column an extraction solvent into which acetic acid is extracted to reduce the concentration of acetic acid, forming a water-rich acetic acid depleted aqueous stream exiting at the bottom of the liquid-liquid extraction column for further treatment and a water-poor fraction containing extraction solvent and water exiting at the top of the liquid-liquid extraction column, feeding the water-poor fraction from the liquid-liquid extraction column to an azeotropic distillation column in fluid communication and downstream of the extraction column where the water-poor fraction is distilled to separate a majority of the remaining water from acetic add, feeding an entrainer into the azeotropic distillation column to form an azeotropic mixture with water and running the azeotropic distillation column, and recovering from the top of the azeotropic distillation column, the azeotropic mixture including water and the entrainer, and from the bottom of the column an acetic acid-rich and water poor liquid stream.