Isopropanol (IPA) is widely used as a drying solvent and cleaning agent in the electronics, pharmaceutical, and fine machine parts industries. With use, the IPA becomes contaminated with water, Typically the solution cannot be used when the water content exceeds about 15 to 20 wt% water. Because of the water-IPA azeotrope at 85 wt% IPA, simple regeneration of the IPA by distillation is not possible and many small users send their IPA to a waste solvent recycler. The availability of the MTR SolvSep membrane process offers an alternative for any operator producing more than a few hundred gallons per day of IPA.
In many cases the feed solution to be treated is a mixture of IPA and water, but more complex mixtures can also be treated. For example, a system installed at IPA production plant to treat a ternary azeotrope is shown below.
The feed to the membrane unit was the overhead vapor produced in an IPA production plant. The feed was IPA containing about 6% acetone and 12% water. The membrane unit produced a dry product containing <0.5 Wt% water. Essentially complete recovery of the IPA and acetone content of the feed was achieved.
A 70m² 3,500 ton/year IPA production plant