Study On The Process Of Cascaded Total Reflux Batch Distillation

This paper proposed and studied a new operation—The cascaded total reflux batch distillation. This method was proposed on the basis of batch distillation with dynamic accumulation and continuous rectification in mode of columns in series. This new mode used the total reflux operation to make full use of the separation efficiency, and the mode of periodic liquid material exchange made the operation of columns in series come true. This new method can add columns according to the requirement of separation. As a whole, this new operation is a very promising operation and can be applied widely.In this paper, the experimental study investigated a cascaded total-reflux batch distillation. Two mixtures which have low relative volatilities, ethanol-isopropanol alcohol and ethylbenzene-p- xylene have been used in the systems with two columns and three columns.This paper provided a simplified mode to simulate a process of total reflux batch distillation in mode of periodic liquid material exchange between columns . Material balance equations of reboiler, trays, condenser were studied and the simulation used two-point implicit method andθcorrector method. The trends of top and bottom temperatures of each column and concentration of each top product with time were investigated.The experiments of two columns in series and three columns in series proved the feasibility of this new operation. According to the model we set up, this paper computed the two mixtures on the conditions of two columns and three columns. The comparison of model predictions of two mixtures with different relative volatilities with experimental results showed that the results of simulation and experiment were close agreeable.