Method for extracting alcohols from an initial mixture comprising alcohols in aqueous phase

A facility for extracting alcohols from an initial mixture (1) comprising isopropanol and butanol, and optionally further comprising ethanol and/or acetone, in aqueous phase, said facility comprising:

• a first section for distillative separation performed by at least one isopropanol-butanol distillation column (III) which is equipped with a top condenser (c3), wherein the first section for distillative separation is capable of separating said initial mixture, or a mixture deriving from said initial mixture, into a water-isopropanol or water-isopropanol-ethanol azeotrope stream (6) at a top of isopropanol-butanol distillation column (III) and into a water-butanol azeotrope stream (7) at a bottom of isopropanol-butanol distillation column (III),
• a second section for distillative separation comprising at least one water column (8) for recovering water and at least one butanol column (9), the second section for distillative separation capable of separating the water-butanol azeotrope stream (7) into water and butanol by a hetero-azeotropic distillation wherein the butanol column (9) is equipped with a reboiler (r5) for heating a bottom stream removed from the butanol column (9), and
• a heat exchanger, which is common to the isopropanol-butanol distillation column (III) and to the butanol column (V), for providing a thermal transfer from the water-isopropanol or water-isopropanol-ethanol azeotrope stream (6) to the bottom stream of the butanol column (V), wherein said heat exchanger incorporates said condenser (c3) and said reboiler (r5), and
• optionally an additional condenser for removing excess heat from the water-isopropanol or water-isopropanol-ethanol azeotrope stream (6).