Batch distillation at total reflux

Batch distillation with variable reflux

The objective is to distillate about 2000 kg of a water-ethanol mixture with ethanol mass fraction of 25%, and to obtain a distillate at more than 90% of ethanol, a residue at less than 0.5% of ethanol, and an intermediate fraction (we could also set a spec for it but we don't).

Remark: you can also put constraint on inter-fraction composition, and/ot try to distillate with minimal energy consumption