The study is concrened with the separation of binary mixtures in the fractional batch distillation under various conditions of still composition, relative volatility, reflux ratio and holdup.
The rate of separation is defined as the rate of change in the still composition with respect to the operating time. Under proper assumptions a theoretical equation relating the still composition with the operating time was derived as;
ln（x_so(1-x_s）/x_s(1-x_so) + k(x_so-x_s/(1-x_s)(1-x_so))=(V/R+1)․θ
The equation was compared with experimental results obtained with two binary mixtures, i.e., benzene-toluene and benzene-carbon tetrachloride, in a Oldershow-type batch distillation apparatus.
The equation predicted reasonably well the experimental results for the benzene-toluene system. For the benzene-carbon tetrachloride system the equation tended to agree with experimental results as the concentration of the more volatile component increased.