Fortunately, the PVCC system using a two-stage condenser worked very well. When the phenol-enriched vapor stream
flowed through the first stage (cooled by a brine solution at 15 1C), solid deposition occurred in the first cold trap to form
phenol crystals. For the separation of conjugate solutions with high melting points, pure crystals may be obtained under
vacuum conditions by desublimation of the vaporous organic compound on the downstream side of pervaporation membranes. Then the remaining permeate vapor (i.e., phenol and water) continued to flow through the second cold trap
(immersed in liquid nitrogen at 196 1C) where the permeate vapor was completely condensed and collected. Because a
significant portion of phenol that has permeated through the membrane was crystallized in the first cold trap, the concentration of phenol in the second trap was only 18,000 ppm, which can be sent back to the feed tank for further recovery.