In my previous paper. total reflux removal distillation as a kind of batch distillation was discussed. This paper introduces the concept of a standard separation where the average distillate composition at 80 per cent of nominal cut point corresponds to 95 mole per cent in a more volatile component. The calculation is made on the theoretical plates which are required for carrying out such a separation by the total reflux removal distillation.
Fig. 1 shows the calculated results. According to these results, the number of theoretical plates required for the standard separation is shown by the following simple equation having relation with the relative volatility, charge composition and holdup:
(7)
Eq. (7) is also applicable, together with the following Eq. (8), to the calculation of the standard separation by means of the usual batch reflux distillation having finite reflux ratio. R(α-1)=25 (8)
Assumption involved in the derivation of the above equations is as follows:
i) Mixture is binary component.
ii) Usual simplifying assumption of distillation is justified.
iii) Relative volatility is constant.
iv) Holdup on each plate is equal.