Isopropanol (IPA) is used as solvent in pharmaceutical and chemical production processes. Used IPA often contains water and impurities, which must be removed before it can be reused. If the spent isopropanol contains heavy boiling impurities, a combination of distillation and vapor permeation is applied to purify this mixture. The main purpose of the distillation column is the separation of the heavy boiling components and the concentration of IPA and water up to close to the azeotropic mixture before the IPA stream can be dehydrated with vapor permeation to the specified quality, typically below 0.5 wt.% of water. The permeate stream from the membrane section can be recycled to the column.
m-PS offers three types of plant concepts which can be applied to isopropanol dehydration:
- continuous vapor permeation
- combination of distillation and vapor permeation
- pervaporation with permeate stripping
