Dynamic Behavior of Alternative Separation Processes for Ethanol Dehydration by Extractive Distillation

Abstract

Ethanol is attracting the attention of researchers because of its potential in reducing the dependence on crude oil together with the possible reduction in the pollution associated with the combustion process. The ethanol dehydration process is significant in terms of its production cost. Recently, new distillation sequences have been proposed for the separation of pure ethanol from the fermentation broth. Extending the concept of thermally coupled structures and column sections recombination, already successfully applied to ideal mixtures, it was possible to generate new distillation sequences for azeotropic mixtures. Those configurations are proven to exhibit lower energy consumption together with reduced capital cost compared to the classical sequence proposed in the literature. The aim of this work is the study of the controllability properties under closed-loop operation. Simulation results indicate that the presence of a side stream in extractive distillation sequences does not necessarily provide operational disadvantages; additionally, results also suggest that control properties are ruled by the kind of solvent used.

Effects of intensification on process features and control properties of lignocellulosic bioethanol separation and dehydration systems

“…distillation systems in industrial practice [46][47][48]. First, we controlled sump levels by manipulating exiting liquid streams, controlled operating pressures by manipulating either exiting gas streams or condenser duty for distillation columns, and controlled drum levels in the distillation columns by manipulating overhead flowrates.…”

Control of extractive distillation processes with intermediate impurities removed as a side withdrawal from the extractive distillation column

“…Although the dynamic control of some alternatives has been investigated, [14][15][16][17][18] difficulties may exist when introducing impurities.…”

Effect of ionic liquids as entrainers on the dynamic behavior of ethanol-water extractive columns

“…Mauricio-Iglesias et al [29] evaluated the influence of heat integration in the ethanol-water distillation process, showing that the energy savings are achieved at the expense of a deterioration in the process controllability. Ramírez-Marquez et al [30] analyzed the dynamic behavior of alternative separation processes for ethanol dehydration by extractive distillation, considering different intensified arrangements based on thermally coupled distillation systems. They also analyzed the use of two different solvents, glycerol and ethylene glycol, and their results suggested that solvent selection affects the optimal choice of control structures for such complex columns.…”