Extractive Distillation Column to Separate Isopropyl Alcohol from Water
The binary mixture of water and isopropyl alcohol (isopropanol or propan-2-ol) presents a positive azeotrope at 1 atm. This azeotrope contains mole % isopropanol. It is possible to break this azeotrope using extractive distillation. Possible entrainers include: (1) 1,2-ethanediol or ethylene glycol, (2) DSMO (or dimethyl sulfoxide), (3) -methyl-2-pyrrolidone or NMP, (4) -methyl-2-piperidone, and (5) -methyl-6-caprolactam.[more]
In this Demonstration, DSMO is used as an entrainer in an extractive distillation column. The column has 41 plates, a partial reboiler, and a total condenser. This column has an upper feed entering the column at plate 5 and containing pure DSMO with a flow rate of 1708 mol/min. The column has also a lower feed entering the column at plate 25 and containing mole isopropanol and mole water. This lower feed has a flow rate of 1666 mol/min. You can set the reflux and reboil ratios, and . For and , the distillate obtained is almost pure isopropanol ( mole %) and the bottom is a mixture of water mole %) and DSMO mole %), which can be easily separated in a second distillation column—the entrainer regeneration column.[less]
For more information, see S. Arifin and I–L. Chien, Design and Control of Isopropyl Alcohol Dehydration via Homogeneous Azeotropic Distillation Using Dimethyl Sulfoxide as Extractive Agent.