DISTILLATION OF BINARY-MIXTURES WITH CAPILLARY-POROUS PLATES

Distillation of liquid mixtures using capillary porous plates is a new process which depends upon the use of the intermolecular interactions between solids and liquids to alter the normal vapor-liquid equilibri um of a given mixture. Distillation of different binary mixtures, name ly ethanol-water, ethanol-benzene, and acetone-ethanol systems, of dif ferent compositions was experimentally studied in a continuous distill ation column equipped with four, five, or six porous sintered stainles s steel fractionating plates of 13.5 mu m pore diameter as well as six normal sieve plates. The results showed that the main factors affecti ng the separation efficiency in a given porous plate are the polarizat ion of the pure liquids and the polarization difference between the mi xture components. For the ethanol-water system, the results showed tha t while no separation was achieved in a distillation column with conve ntional stages, the azeotropic point of this system was broken in the distillation column with porous plates. A distillate of about 94 mol% ethanol was obtained for a feed of the azeotropic composition, i.e., 8 9.7 mol% ethanol. For the ethanol-benzene system, the azeotropic point was shifted from 40 mol% ethanol to about 30 mol% ethanol. For the ac etone-ethanol system, there was no significant difference between the results obtained with normal stages and those with the porous plates. These results are in agreement with the developed theory.