EVALUATION OF THE DYNAMIC BEHAVIOR OF AN EXTRACTIVE DISTILLATION COLUMN FOR DEHYDRATION OF AQUEOUS-ETHANOL MIXTURES

The dynamic characteristics of an extractive distillation column for d ehydration of aqueous ethanol mixture are investigated. The objective is to analyse the sensibility and stability of the process to perturba tions in its main variables to be possible to recommend the best varia bles to be manipulated. Taking this into account, it was developed a m odel which considers the main phenomena taking place, i. e., it incorp orates the effects of simultaneous mass and heat transfers as well as hydraulic behavior of the plates. Furthermore, it contains a rigorous consideration of the phase equilibria representation, once, in this ca se, the system is highly non-ideal. The mathematical modeling results in a system of differential equations which is solved by Gear's proced ure. The dynamic behavior was analysed from the knowledgment of the ef fect of composition variation of the feed stream, rate of solvent and reflux flow rate. The quality of the final product can be achieved man ipulating the solvent flow rate once the temperature of the upper part of the column, p.e., plate 18 and 22, is very sensitive to the perfor med modifications.