The traditional recovery of ethanol from fermentation broth concentrates up to 95.6% (w/w) by simple distillation followed by
an azeotropic distillation step or by molecular sieves to dehydrate ethanol up to 99.9% (w/w) as a fuel-grade ethanol. The total energy input for those two distillation steps is 7.63 MJ l 1 to make fuel- grade ethanol (Dzenis and McNab, 1984; Duff and Murray, 1996). For a fermentation broth containing approximately 9% ethanol, the distillation cost represents 40–60% of the total plant energy consumption to make fuel-grade ethanol