Abstract This study investigates the distillation of ethanol–water mixture in a laboratory-scale distillation column. The objectives are to determine the number of theoretical stages under total reflux and to compare experimental results with Fenske equation predictions. The effect of the reflux ratio on distillate flow rate and ethanol purity was also examined. Experiments were conducted under steady-state conditions, and compositions were determined by density and refractive index measurements. The theoretical analysis based on the McCabe–Thiele method shows good agreement with the experimental results, with deviations in mass balance remaining within 2–3 %, validating the predictive reliability of the Fenske approach. To enhance process efficiency, heat recovery and solar-assisted integration strategies were evaluated. Two configurations were analyzed: a condenser–feed heat exchanger for feed preheating and a solar thermal stage using flat-plate or evacuated-tube collectors. Results reveal a notable reduction in boiler heating demand, confirming that solar-assisted heat recovery can significantly improve the energy efficiency and sustainability of ethanol–water distillation.
Frikha et al. (2026) studied this question.