Obtenção de etanol anidro via destilação extrativa com retirada lateral.

Abstract

Distillation is one of the oldest and most used separation processes that exist in chemical and petrochemical industries worldwide. In cases of azeotropic mixtures, simple distillation is unable to perform the separation at a certain composition, so they are separated via azeotropic distillation. This paper deals with azeotropic distillation and the process of obtaining anhydrous ethanol was chosen as a case study. Traditionally, there are two different configurations used to produce ethanol anhydrous by azeotropic distillation. One of them is the heterogeneous azeotropic distillation (azeotropic distillation) and the other one is the homogeneous azeotropic distillation (extractive distillation). In both configurations, it is necessary to add a third component to promote separation. In azeotropic distillation, the third component is called Material Separation Agent and in extractive distillation, the third component is called solvent. For both configurations it is necessary to use two distillation columns. The first column recovers pure component from the original mixture at the top of the column while the second column recovers the Material Separation Agent or the solvent, which returns to the azeotropic column. The overall purpose of this study is to evaluate the performance of a new configuration of extractive distillation process for producing anhydrous ethanol using only one column with a side stream withdrawal. The solvent used to break the azeotrope was ethylene glycol. The specific purposes are to determine the design and process optimized conditions and to evaluate the transient behavior of the column for different operating conditions at the steady state. Sensitivity analyzes for different design and process conditions, process optimization to reduce energy consumption and apreliminary evaluation of the transient behavior of the column were performed using computer simulations. In terms of product composition, as well as for the overhead stream (where anhydrous ethanol is recovered), close attention should also be given to the sidestream withdrawal and bottom stream. The results showed the strong influence of the variables in the compositions of the three product streams. After optimization, it was possible to achieve a reduction of 8.6% in the reboiler heat duty.