Abstract

Isopropanol, butanol, and ethanol (IBE) is an alternative biofuel. However, dehydration of IBE is complicated by the presence of three binary azeotropes. The new distillation system proposed in this work for IBE dehydration was a combination of azeotropic and extractive distillation. Butanol in a complex reflux system, without an additional entrainer, broke the azeotropic behavior of isopropanolwater and ethanol-water. Decantation dismissed butanol-water azeotrope. The distillation system was evaluated using Aspen Plus software. The alternative distillation system achieved an energy requirement between 6.5 and 8.2 MJ-fuelikg-IBE. The fuel requirement using steam compression distillation reduced to 3.4-4.1 MJ-fuelikg-IBE. The energy efficiency of IBE dehydration was between 0.72 and 0.79. IBE recovery was compared with alternative biofuels. Energy requirement of IBE was 0.92-1.4 and 1.4-2.4 times higher than that of isobutanol and ethanol dehydration, respectively. However, IBE fermentation reached an equivalent energy efficiency by hydrogen production. Biofuels recovery from broth of conventional reactors by heat-integrated distillation achieved the highest energy efficiency. (C) 2017 Elsevier B.V. All rights reserved.