Entropy Production Analysis in Extractive Distillation Using Non-Equilibrium Thermodynamics and a Rate Based Model

Entropy generation (EG) in an extractive distillation column for ethanol dehydration was determined. The rate based model and non-equilibrium thermodynamics (NET) leads to quantify separately the EG due to interface heat and mass transfer and mixing. Additionally, this model allows estimating the effects of operational conditions such as reflux ratio and feed condition on the EG. The results obtained show that mixing effects at the feeding points (hydrated ethanol and separation agent) and interface mass transfer are the main sources of EG with 55% and 41% of total EG, respectively. The significance of this work is the use of a rate based model and NET theory as a tool for energy use analysis in multicomponent distillation processes. EG analysis is the starting point to define new operational strategies and design characteristics that allow a more efficient energy use.