fficient Bioethanol Dehydration in Azeotropic and Extractive Dividing-wall Columns

The industrial production of anhydrous bioethanol requires energy demanding distillation steps to overcome the azeotropic behaviour of ethanol-water mixture. This study proposes novel distillation technologies for enhanced bioethanol dehydration, by extending the use of dividing-wall columns (DWC) to energy efficient azeotropic and extractive distillation (AD and ED). The classic sequence of two distillation columns and the alternatives based on DWC are optimized using the state of the art sequential quadratic programming (SQP) method. A mixture of 85%mol ethanol is dehydrated using ethylene glycol or pentane as mass separating agents. The results of the rigorous Aspen Plus simulations show that energy savings of 10-20% are possible for the novel process intensification alternative based on DWC, while using less equipment units as compared to the conventional AD and ED configurations.