Phase equilibrium model for the separation of ethanol-water solution using super- and subcritical propane solvent extraction

Abstract

To dehydrate a fermented or synthetic crude ethanol using super-and subcritical propane solvent extraction, we previously measured phase equilibrium data for the C3H8-C2H5OH-H2O system9). In this work the applicability of phase equilibrium models was examined using existing well-known PT-EOS, GC-EOS and a NRTL-NRTL solution models. The estimations of binary phase equilibria by these models are relatively accurate, except for PT-EOS, using the random mixing rule. It is found that the solution model NRTL-NRTL is the most practicable one for the C3H8-C2H5OH-H2O ternary system at the extraction stage. At the propane azeotropic distillation stage, GC-EOS gives the most accurate estimation. Although it is a little less practicable, it can be used for design concept. At the propane stripping stage, any equation-of-state method is sufficiently practicable. © 1993, The Society of Chemical Engineers, Japan. All rights reserved.