Process system for separating chemicals, distillation column arrangement, and method of separating chemicals

A distillation column arrangement comprising:

• a first distillation column (100) having a top (104),
• a second distillation column (142) having a top (146) and a bottom (148),
• a first decanter (122) having a top and a bottom, and
• a third distillation column (106) having a top (112) and a bottom (110),
• wherein:
• the first distillation column (100) being configured to operate in a pressure range at or below 1 bar and receive a mixture that comprises water and at least two organic acids including formic acid and acetic acid, and an extractant that comprises at least one of the following:
• hexanol, an ester of hexanol with at least two organic acids and 2-methylpentanol,
• said first distillation column (100) is configured to form a heterogeneous azeotrope of water and extractant at said top (104) on the basis of reactive heteroazeotropic extractive distillation and without controlling chemical reactions of the extractant and said at least two organic acids, wherein said first distillation column (100) is configured to remove said heterogeneous azeotrope of water and extractant through said top (104) into the first decanter (122) for separating water from said at least two organic acids;
• said first decanter (122) is configured to separate the heterogeneous azeotrope of water and extractant into an organic phase comprising the extractant which, as a substance less dense than water, rises to said top of the decanter (122), and an aqueous phase which, with a greater density than the organic phase, remains at said bottom of the decanter (122);
• said first distillation column (100) is configured to feed a portion of said at least two organic acids, extractant and water to the third distillation column (106);
• said third distillation column (106) is configured to form extractant at said bottom (110) for at least one of recovery or recycling, and the third distillation column (106) is configured to form, based on distillation, a mixture of water and said at least two organic acids at said top (112) for at least one of recovery or recycling;
• said second distillation column (142) is configured to receive furfural and a mixture of water and said at least two organic acids;
• and
• said second distillation column (142) is configured to:
• form a heterogeneous azeotrope of water and furfural at said top (146) on the basis of heteroazeotropic distillation, wherein said second distillation column (142) is configured to remove through said top (146) for separating furfural from said at least two organic acids;
• form said at least two organic acids and water at said bottom (148) on the basis of heteroazeotropic distillation;
• and
• feed said at least two organic acids and water from the bottom (148) of said second distillation column (142) to the first distillation column (100) for separating said at least two organic acids and the furfural from one another.

A method for separating chemicals, said method comprising the steps of:

• receiving (700) in a first distillation column (100), which operates in a pressure range at or below 1 bar, a mixture that comprises water and at least two organic acids including formic acid and acetic acid, and an extractant that comprises at least one of the following:
• hexanol, an ester of hexanol with at least two organic acids and 2-methylpentanol;
• forming (702) in said first distillation column (100) a heterogeneous azeotrope of water and extractant at a top (104) of the first distillation column (100) on the basis of reactive heteroazeotropic extractive distillation, wherein said first distillation column (100) removes said heterogeneous azeotrope of water and extractant through said top (104) to a first decanter (122) for separating water from said at least two organic acids;
• separating in the first decanter (122) the heterogeneous azeotrope of water and extractant into an organic phase comprising the extractant which, as a substance less dense than water, rises to a top of the decanter (122), and an aqueous phase which, with a greater density than the organic phase, remains at a bottom of the decanter (122);
• feeding a portion of said at least two organic acids, extractant and water from the first distillation column (100) to a third distillation column (106);
• and
• forming extractant at a bottom (110) of said third distillation column (106) for at least one of recovery or recycling, and forming a mixture of water and said at least two organic acids by distillation at a top (112) of the third distillation column (106) for at least one of recovery or recycling.