Simulation and optimization of heterogeneous azeotropic distillation process with a rate-based model

A rate-based simulation method for sieve tray columns is developed with the correlations of clear liquid height and mass transfer rate that were obtained in our previous experiments of the homogeneous and heterogeneous ternary distillation with a sieve tray column. The simulation method is applied to an ethanol dehydration process that consists of a dehydration column and an entrainer recovery column. In the simulation study, the effects of tray specification, overhead vapor concentration, locations of main feed and recycle flow, reflux ratio and recycle flow rate on separation performance of the columns are investigated. The simulation results show that increase of the reflux ratio and recycle flow rate decreases the necessary number of trays of the dehydration column to achieve a specified separation, but it increases the heat duties of the process. Then, the economical analysis of the process is carried out, and the optimum operation conditions of the process are discussed.