Using an internally heat-integrated distillation column for ethanol-water separation for fuel applications

Distillation is widely used as a key process to concentrate ethanol from fermented broth in the Brazilian sugarcane industry. In this study, Aspen Plus® was used to compare the energy demand for a heat-integrated distillation column (HIDiC) both with and without heat panels with the energy demand for a conventional distillation column for a separation process that could be applied to the Brazilian bioethanol market. The overall convective heat transfer coefficient, area, and other parameter values were calculated and combined with the HIDiC simulation. The reboiler duty results showed that by assuming a fixed fraction of the fluids exchanged energy at the panels, energy savings of 77% were possible with the HIDiC column compared to the energy requirements of a conventional column. This approach also allowed a stage-by-stage calculation of the overall heat transfer coefficient instead of assuming a constant value.