As the pharmaceutical industry adopts continuous processes, batch distillation for solvent exchange will need to be replaced with a continuous distillation process. Cyclic distillation is adapted to solvent exchange, and a simplified calculation method that does not assume constant molar overflow is developed for binary systems. A three-stage cyclic distillation for exchange of methanol with water designed for a bottoms product that is 90% water produces a 99.3% methanol distillate, uses 25.4% less solvent than constant volume batch distillation, and is roughly equivalent to a five-stage continuous distillation. When water is the feed solvent and is exchanged with methanol, a three-stage cyclic distillation uses 54.4% and 40.0% less solvent than constant volume batch distillation and a three-stage continuous distillation, respectively.

中文翻译：

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二元溶剂交换的连续循环蒸馏：批处理堆栈

由于制药行业采用连续过程，因此需要用连续蒸馏过程代替间歇蒸馏进行溶剂交换。循环蒸馏适合于溶剂交换，并且针对二元系统开发了一种简化的计算方法，该方法不假定摩尔恒定溢流。设计用于塔底产物（水含量为90％）的三阶段循环蒸馏法，用于与水交换甲醇，生成99.3％的甲醇馏出液，与恒定体积的分批蒸馏相比，使用的溶剂少25.4％，大致相当于五阶段连续蒸馏蒸馏。当水是进料溶剂并与甲醇交换时，三阶段循环蒸馏所用的溶剂分别比等体积分批蒸馏和三阶段连续蒸馏少54.4％和40.0％。