Energy-efficient extractive distillation combined with heat-integrated and intermediate reboilers for separating acetonitrile/isopropanol/water mixture

A conventional triple-column extractive distillation is researched for the separation of acetonitrile/isopropanol/water mixture with ethylene glycol (EG) as entrainer. In this article, the pressure-relative volatility curve is investigated to find the suitable pressure of column. To achieve the further energy saving, three heat-integrated schemes and two heat-integrated combined with intermediate reboilers schemes are researched based on the conventional extractive distillation. Both two heat integration with intermediate reboilers schemes shown the better performance than other schemes since the further analysis of the energy, exergy, economic and environment (4E) were investigated. For the most energy saving design, PHI-IHI2, it has 48.50% energy-saving, 70.73% exergy efficiency enhanced, 36.24% reduction in total annual cost (TAC) and 48.55% reduction in gas emissions with the comparison of the conventional extractive distillation (CED) process. The result shows the extractive distillation combined with heat-integrated and intermediate reboilers presented great energy-efficient, economy saving and environment friendly for separating acetonitrile/isopropanol/water mixture.

Automated summary

The research on conventional triple-column extractive distillation using ethylene glycol as entrainer for the separation of acetonitrile/isopropanol/water mixture showed that the heat-integrated schemes with intermediate reboilers had better performance in terms of energy saving, exergy efficiency, economic benefits, and environmental impact compared to the conventional extractive distillation process. This study highlights the potential for energy-efficient, cost-effective, and environmentally friendly separation techniques in chemical processes.