Abstract
Distillation-Pervaporation Hybrid Systems (DPHS) are a relatively novel technology for separating multicomponent azeotropic mixtures, due to pervaporation is not limited by the liquid-vapor (LV) equilibria. However, conventional Distillation-Pervaporation Hybrid Systems, where the pervaporation unit is externally connected to the distillation column, have several drawbacks in the pervaporation unit, for instance high resistance to heat and mass transfer and an inter stage heating system is required between the pervaporation modules. Distillation-Pervaporation in a Single Unit (DPSU) is a novel concept where the pervaporation membrane is located inside the distillation column working as a packing bed in a section of the column. Due to it is a new concept, there is little data about its separation behavior. However, DPSU is able to overcome distillation boundaries. In this work, a simplified model is used to evaluate the separation of ternary homogenous azeotropic mixtures and thermodynamic conditions in a DPSU column. A pervaporation sections located in rectifying and stripping sections were studied. Two topological types, based on Serafimov’s topological classification, were selected as case studies: acetone-isopropanol-water (1.0-2) and ethyl acetate-ethanol-methanol (2.0-2b) mixtures. The effects of the DPSU column on the mixture topology, such a perturbation of stationary points, are studied. It is possible to overcome distillation boundaries using a selective membrane but also new stationary points in middle of the composition space appear.
