HWAHAK KONGHAK, Vol.34, No.2, 201-207, April, 1996
공비증류에 의한 MEK-물-톨루엔 혼합물로부터 MEK 분리에 관한 이론적 연구
A Theoretical Study on the Separation of MEK from MEK-Water-Toluene Mixture by Azeotropic Distillation
초록
MEK-물-톨루엔 최저 공비혼합물을 첨가제의 다른 선택도에 의한 공비증류방법으로 분리를 시도하였다. 무한희석 활동도계수의 비를 이용하여 최적의 첨가제로 아세톤을 선택하였다. 또한 UNIFAC 모델을 이용하여 첨가한 아세톤 양과 MEK-물-톨루엔 삼성분 혼합물 조성에 따른 2상 존재여부를 확인하였다. 아세톤을 상온에서 2상을 현상하는 MEK-물-톨루엔 혼합물 양의 3.14배 이상 첨가하였을 때 삼성분 혼합물 조성에 관계없이 단일상이 되며 공비증류과정에서 공비점도 제거되어진다. UNIQUAC 모델을 이용한 증류공정모사를 통해 조작조건들의 영향을 고찰함으로써 증류단수를 최소로 하는 최적의 첨가제 양을 구할 수 있었다. 그리고 MEK 조성이 증가할수록 공비증류에 필요한 이상증류단수는 증가하였고, MEK 조성이 일정하면 이상증류단수는 물과 톨루엔의 조성에 무관함을 확인하였다. 또한 첨가제 양 및 환류비 변화에 따른 최적 급단수 계산 가능하였으며 최소환류비가 0.6이 됨을 파악할 수 있었다. MEK, 물, 톨루엔이 각각 40, 30, 30몰%인 MEK-물-톨루엔 혼합물로부터 공비탑하부 생성물로서 비공비혼합물인 MEK와 톨루엔, 공비탑상부 생성물로서 물과 아세톤으로 분리하는 경우, 아세톤이 공비증류에 의한 MEK-물-톨루엔 혼합물로부터 MEK 분리삼성분 혼합물 양의 5배가 사용되고 환류비가 0.9일 때 56몰% MEK와 44몰% 톨루엔의 공비탑하부 생성물을 얻을 수 있었다. 이 때 최적급단은 6째단부터 11째단사이가 되고 이상증류단수는 14단으로 최소화되었다.
MEK(methyl ethyl ketone) can be separated from MEK-Water-Toluene azeotropic mixture by azeotropic distillation using the selectivity of entrainer. Acetone was selected as the best entrainer by comparing the ratio between infinite dilute activity-coefficients. Depending on the added amount of acetone and the concentration of MEK-Wa-ter-Toluene mixture, the presence of two phase was identified by UNIFAC model. When acetone was added more than 3.14 times the amount of MEK-Water-Toluene mixture, the mixture formed a single phase and the azeotropic point was eliminated. The optimum amount of entrainer to minimize the plate number was calculated through the simulation of distillation process by UNIQUAC equilibrium model. The number of ideal plates increased with MEK composition and was independent of water and toluene composition. Also, the optimum feed-plate location was calcula-ted at each reflux ratio for various amounts of entrainer, and the minimum reflux ratio was identified as 0.6. For the case that brought Acetone-Water as bottom product and MEK-Toluene as distillate from MEK-Toluene as distillate from MEK-Water-Toluene mixture where the composition of MEK, water and toluene compositions was 40, 30, 30mole%, respectively, 14 ideal plates were required for the best results when the reflux ratio was 0.9% and the ratio of entrainer to feed was 5. The bottom product was composed of 56 mole% of MEK and 44 mole% of toluene and the optimum feed-plate was located between the sixth and the eleventh in this case.
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