Multiple effect concentration of ethanol by ohmic-assisted hydrodistillation

- OAHD performed second and third distillation steps of ethanol and results were compared with conventional HD.
- OAHD increased the ethanol concentration to 84% (v/v) which was higher than HD obtained product.
- The proposed method was superior in terms of process control, time and energy consumption.
- Substitution of HD systems by OAHD can help to protect the environment.

Our previous work on ethanol distillation by ohmic-assisted hydrodistillation (OAHD) successfully concentrated ethanol from 10 to 50% (v/v). In this work, two additional concentration steps were conducted using the 50% (v/v) product obtained from the first concentration stage at a constant wattage of 168 W using the same OAHD device. The second distillation step resulted in a product with ethanol concentration of 76% (v/v) and the third step yielded ethanol concentration of 84% (v/v). Results were compared to conventional hydrodistillation (HD), and were indicative that OAHD reduces one third of energy cost in ethanol distillation process. Not only was OAHD superior to HD in terms of time and energy consumption, but also resulted in higher ethanol concentrations than HD after the third step of distillation: 84.3 ± 0.3% vs. 82.5 ± 0.5%, respectively. OAHD also showed better process control and was able to stop the distillation process faster than HD. In both second and third distillation steps, the time required to stop the process with OAHD (1 min) was shorter than for HD process (10 min). The findings of this study further confirm our previous work, and reveal that this emerging distillation technique has the potential of yielding high concentrations of ethanol from dilute alcoholic solutions in a more economical and environmental friendly way.