Theoretical and Experimental Evaluation of a Distillation–Pervaporation in a Single Unit Column for the Separation of an Azeotropic Mixture

Abstract

A distillation–pervaporation in a single unit (DPSU) column previously was theoretically studied based on mixture thermodynamics. It was observed that the separation inside the DPSU column is not restricted by the thermodynamics of nonideal mixtures as conventional distillation columns, or externally connected distillation–pervaporation (ECDP) columns. In this work, theoretical and experimental evaluations of a DPSU column at infinite reflux ratio was performed for the azeotropic mixture of ethanol–isopropanol–water. Silica membranes were used to recover internally water from the DPSU column. Two DPSU column configurations were proposed: (1) the membrane section located on the top of the column and (1b) an intermediate membrane section. The results showed the distillation boundary was internally overcome by both DPSU column configurations, since the water removal by pervaporation modified the volatility of the components, as compared to a conventional distillation. No thermodynamic restrictions were observed close to the distillation boundaries. In addition, theoretical results from the simplified model derived in previous works were compared to the experimental data. Good agreement between theoretical and experimental results was observed in this work.

Process intensification by integration of distillation and vapor permeation or pervaporation - An academic and industrial perspective

“…They confirmed the feasibility of the PV-inside-distillation column configuration crossing the distillation boundary formed by the azeotropic point through the batch distillation experiments for separating the ethanol-isopropanol-water mixture [123]. Then a series of continuous separation experiments of the ethanol-isopropanol-water mixture in an experimental glass column coupled with the PV membrane was carried out, verifying this technology's theory [124].…”

“…Such a solution is representative of a hybrid separation, as defined by Stankiewicz [122]. In a series of publications, Leon and Fontalvo [123][124][125][126] presented theoretical research and experimental verification of the hybrid separation concept with the membrane inside the distillation column. They confirmed the feasibility of the PV-inside-distillation column configuration crossing the distillation boundary formed by the azeotropic point through the batch distillation experiments for separating the ethanol-isopropanol-water mixture [123].…”