Patent ID: 8268131
Filing Date: 2012-09-18
Classification: B01D,C07C

Abstract:
1. An apparatus for recovering acetic acid from an aqueous solution thereof, comprising: a liquid-liquid extraction column, an azeotropic distillation column in fluid communication with and located downstream of the extraction column, a guard bed containing a catalyst for esterification of alcohol by reaction with acetic acid to form the corresponding ester situated within and near the top of the liquid-liquid extraction column, means for feeding into the 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, means for 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, means for feeding the water-poor fraction into the azeotropic distillation column where it is distilled to separate a majority of the remaining water from acetic acid, means for feeding an entrainer into the azeotropic distillation column to form an azeotropic mixture with the water, and means for recovering from the top of the azeotropic distillation column the azeotropic mixture, and from the bottom of the column an acetic acid-rich and water-poor liquid stream.