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HWAHAK KONGHAK, Vol.11, No.5, 361-370, October, 1973
회분증류공정에 있어서 Holdup Ratio의 효과에 관한 연구-회분증류에 관한 연구(II)-
The Study on the Effect of Holdup Ratio in the Fractional Batch Distillation
초록
본 연구는 제2보로써 비정상상태하에서의 회분증류공정에 있어서 Holdup ratio의 효과를 규명하려 한 것이다. 조작시간에 따른 Still pot내의 농도변화를 증류속도로 정의하여 다음과 같은 이론식을 유도했다.
HRln（xso(1-xs）/xs(1-xso))+μ·Φ․((xso-xs)/(1-xso)) = μ·(V/R+1)․θ
시료는 Benzene-Carbontetrachloride와 Methanol-Ethanol 등의 이성분계를 사용했으며 실험치와 비교검토 결과 상기 이론식과 잘 일치했다. 한편, Reflux ratio가 낮을 때는 Holdup ratio가 증가할수록 분리효과는 증가하였고, Reflux ratio가 높을 경우에는 Holdup ratio가 증가할수록 분리효과는 감소했다. 颡라서 다른 모든 변수를 일정하게 유지시켰을 때 Holdup ratio의 분리효과는 Reflux ratio의 의존함을 알았다. 또 Holdup ratio의 분리효과가 뚜렷이 나타나지 않았을 때의 Reflux ratio를 Critical Reflux ratio라 하였으며 본 연구에서 Benzene-Carbontetrachloride의 Critical Reflux ratio는 9였고 Methanol-Ethanol계에서는 2였다.
HRln（xso(1-xs）/xs(1-xso))+μ·Φ․((xso-xs)/(1-xso)) = μ·(V/R+1)․θ
시료는 Benzene-Carbontetrachloride와 Methanol-Ethanol 등의 이성분계를 사용했으며 실험치와 비교검토 결과 상기 이론식과 잘 일치했다. 한편, Reflux ratio가 낮을 때는 Holdup ratio가 증가할수록 분리효과는 증가하였고, Reflux ratio가 높을 경우에는 Holdup ratio가 증가할수록 분리효과는 감소했다. 颡라서 다른 모든 변수를 일정하게 유지시켰을 때 Holdup ratio의 분리효과는 Reflux ratio의 의존함을 알았다. 또 Holdup ratio의 분리효과가 뚜렷이 나타나지 않았을 때의 Reflux ratio를 Critical Reflux ratio라 하였으며 본 연구에서 Benzene-Carbontetrachloride의 Critical Reflux ratio는 9였고 Methanol-Ethanol계에서는 2였다.
This study is concerned with the separation of binary mixtures in the fractional batch distillation under various conditions of Holdup to charge ratio at constant reflux ratio.
The rate of separation is defined as the rate of change in the still composition with respect to the operating time elapsed. Under proper assumption a theoretical equation relating the still composition with the operating time was derived as;
HRln（xso(1-xs）/xs(1-xso))+μ·Φ․((xso-xs)/(1-xso)) = μ·(V/R+1)․θ
The equation was compared with experimental results obtained with two binary mixtures, I.e., Benzene-CTC （carbontetrachloride） and Methanol-Ethanol, in a Oldershaw-type batch distillation apparatus.
Consequently the equation was found to be substantially agreed with the experimental results, especially for the Methanol-Ethanol system. For the benzene-CTC system the equation tended to agree with experimental results.
Meanwhile, holdup ratio was found experimently to have two counteracting effects on the separation of binary mixtures. Namely, in a series of experimental works, as the reflux ratio was increased above the critical reflux ratio the effect of increased holdup ratio become increasingly unfavorable to sharpness of separation. At reflux ratio below the critical reflux ratio the effect of increasing holdup ratio was favorable. For the Benzene-CTC system （30 plates） the critical reflux ratio was 9, at the Methanol-Ethanol system was 2.
The rate of separation is defined as the rate of change in the still composition with respect to the operating time elapsed. Under proper assumption a theoretical equation relating the still composition with the operating time was derived as;
HRln（xso(1-xs）/xs(1-xso))+μ·Φ․((xso-xs)/(1-xso)) = μ·(V/R+1)․θ
The equation was compared with experimental results obtained with two binary mixtures, I.e., Benzene-CTC （carbontetrachloride） and Methanol-Ethanol, in a Oldershaw-type batch distillation apparatus.
Consequently the equation was found to be substantially agreed with the experimental results, especially for the Methanol-Ethanol system. For the benzene-CTC system the equation tended to agree with experimental results.
Meanwhile, holdup ratio was found experimently to have two counteracting effects on the separation of binary mixtures. Namely, in a series of experimental works, as the reflux ratio was increased above the critical reflux ratio the effect of increased holdup ratio become increasingly unfavorable to sharpness of separation. At reflux ratio below the critical reflux ratio the effect of increasing holdup ratio was favorable. For the Benzene-CTC system （30 plates） the critical reflux ratio was 9, at the Methanol-Ethanol system was 2.