COMPARATIVE STUDY ON OPERATION AND CONTROL OF FOUR BATCH DISTILLATION CONFIGURATIONS WITH VARIOUS OPERATING STRATEGIES

摘要

Over the past twenty years, quite a few batch distillation configurations and operating strategies have been proposed in open literature. However, there is little published paper discussing on the pros and cons of each configuration with some benchmark examples. In this work, operation and control of four batch distillation configurations with various operating strategies to separate mixtures containing no azeotrope are compared. The batch distillation column figurations considered in this paper include: regular batch distillation column (or called batch rectifier), inverted column (or called batch stripper), batch distillation combining the above two operations (or called middle vessel column), and multi-vessel batch distillation. Three different operating strategies are considered in the paper include: fixed reflux/reboil ratio strategy, variable reflux/reboil ratio strategy, and total reflux strategy. Physically realistic two-, three-, and four-component mixtures will be used in the comparative study. Rigorous dynamic simulation of each batch distillation configuration will be established using Aspen DynamicsTM process simulator. In the comparison, no on-line composition analyzer is assumed to be used in the batch operation, thus product quality will be inferred by some temperature measurements. Capacity factor (CAP) introduced by Luyben[1] or the total batch time (Tbatch) will be used for the comparison of various batch distillation configurations.