PURPOSE: To separate a liquid mixture in efficiency equal to a distillation method, by a method wherein a mixed liquid consisting of a liquid (A component) with high polarity and a liquid (B component) with low polarity is permeated through a first membrane to reject the B component and the permeate is permeated through a second membrane to reject the A component.
CONSTITUTION: A mixed liquid consisting of water with high polarity and ethanol with low polarity is introduced into a membrane separation apparatus 1 equipped with positive membrane to be fractionated so as to permeate water and reject ethanol. Ther permeate from the apparatus 1 is sent to a membrane separation apparatus 3 equipped with a negative membrane through a line 2 to be fractionated to permeate ethanol mainly and reject water. The membrane rejected liquid from the apparatus 3 is succeedingly sent to negative membrane separation apparatuses 4, 5 to carry out fractionation treatment similarly. By this method, high concn. water is separated and recovered from the final stage 5 as the membrane rejected liquid. The membrane rejected liquid from the apparatus 1 is sent to a positive membrane separation apparatus 7 through a line to separate and recover ethanol.
TANII HIROKUNI
KIKUCHI KOUICHI
YAMASHITA SHIYUUZOU
| JPS52114577A | 1977-09-26 |