Modelagem termodinâmica do sistema aquoso com etanol visando a otimização da destilação

Abstract

Vapor-liquid equilibrium (VLE) data is important for the development of models to be used in the design and optimization distillation columns. This work provides a systematic research and analysis of experimental literature data starting from vapor pressure of water and ethanol to vapor–liquid equilibrium measurements of the binary mixture. Antoine constants for the vapor pressure were accurately estimated. VLE experimental database approved in the consistency test were used for the reparameterization of the binary interactions “aij” of the UNIQUAC model. With the obtained parameters it was possible to carry out simulations of the behavior of the ethanol-water system at 1 atm and 10 atm, obtaining azeotrope points of 87.7% molar (94.8wt%) and 82.2% molar (92.2wt%), respectively. These pressures are usually applied in in the Pressure-Swing Distillation (PSD) process, which is used due to the azeotropic behavior of the ethanol-water system to get anhydrous ethanol. Temperature composition diagrams (Txy) in the pressure of the separation process were generated and flash distillations were also simulated. In flash distillation it was possible to observe the result of a more concentrated ethanol at the exit of the separator, demonstrating that the model applies properly to the PSD process.