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Seminars
A New Separation Method - Distillative Freezing
Professor Barry (Lie-Ding) Shiau
Department of Chemical & Materials Engineering
Chang Gung University
When: Thursday, August 31, 2006
Time: 2:30 PM to 3:30 PM
Where: 1070 Duncall Hall
Abstract:
A new separation technology, called distillative freezing (DF), is introduced to separate the mixture of the volatile compounds with close boiling temperatures at a reduced pressure. Basically, the DF process is operated at triple point condition, in which the liquid mixture is simultaneously vaporized and solidified due to the three-phase equilibrium. It results in the formation of pure crystals, and liquid phase and vapor phase of mixtures. The process is continued until the liquid phase is completely eliminated and only the pure solid crystals remain in the feed.
DF is a distillative crystallization technology, which combines distillation and crystallization to result in pure crystal products. Compared to conventional crystallization, filtration or centrifugation is not needed since no mother liquor is present with the pure solid crystals. In addition, crystal washing is not required since only the pure crystals remain in the feed and no impurities are adhered on the crystal surfaces at the end of the operation. In DF, pure crystals are obtained due to the three-phase equilibrium by controlling temperature and pressure. As the heat of vaporization is supplied by the heat of crystallization in DF, it is an energy-conserving separation method. In addition, no chemicals are added in DF. It is also a clean separation technology.
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