Investigation of Process Alternatives for the Separation of Ethanol, N-Butanol and Water Ternary Mixture

Biofuel production is an ever current topic, as bioethanol and biobutanol have a great potential to partially or completely replace fossil fuels in the automotive industry due to their attractive characteristics. They are usually produced by fermentation resulting in a highly diluted mixture, which poses a challenge to the downstream processing and the production of pure alcohols. In the course of this work, conventional separation systems of simple, extractive and heteroazeotropic distillation are compared with hybrid distillation-pervaporation systems for the separation of a ternary ethanol-n-butanol-water (EBW) mixture. Pervaporation (PV) is studied as an option for the final dehydration of the alcohol-water mixtures due to its great industrial potential in the separation of azeotropes. Simulations are carried out in ChemCAD® flowsheeting software, and the process alternatives are evaluated in an economic point of view, revealing the potentials and drawbacks of PV in a complex separation task.