Distillation plant performance implications of high distillate-purity during ethanol-water pre-concentration

Abstract

This paper presents the effect of distillate purity on the performance of ethanol-water distillation column before azeotrope. The factors  affected include the required number of stages, reflux ratio, reboiler and condenser duties, investigated using different feed thermal  conditions. The model was set using Aspen Plus® V10 simulation software and used to establish the impact of operating conditions due  to high distillate purity. The aim was to increase distillate purity while minimizing energy consumption. The research highlights the  importance of modeling and simulation for optimizing distillation processes to reduce energy consumption. The feed flow rate was 1000  kmol/h, with composition ranging from 0.1 to 0.6 mol/mol. The number of stages varied from 8 to 20 while the reflux ratio ranged  between 1 and 8. The required number of stages, reflux ratio, condenser and reboiler duties increased with increasing desired distillate  purity. The reboiler and condenser duties increased with distillate purity according to 3rd order polynomial functions. It was concluded  that the pre-concentration column can concentrate dilute solutions to higher purity closer to the azeotropic point. Further studies were  recommended on the non-linear behavior and large energy consumption.