Development and intensification of a four-column hybrid process of heteroazeotropic distillation and pressure-swing distillation

This article develops a four-column hybrid process of hetero-azeotropic distillation and pressure-swing distillation (HAD-PSD) for separating a ternary multi-azeotropic mixture i.e., an organic aqueous solution with a low concentration of isopropanol (IPA) and diisopropylether (DIPE). For improving its economic and energetic performances, an intensified process by heat pump and dividing wall column is proposed, namely HAD-DWC-VRC-PSD. The quantified performance improvement over the HAD-PSD process reveals that the annual energy cost is drastically reduced by 39.7 % from 45.5-27.4 $ per tonne of IPA and DIPE while the total annual cost is cut by 11.7 % from 92.0-81.3 $ per tonne of IPA and DIPE. Besides, the thermodynamic efficiency is increased from 19.80 % to 25.96 %, and the carbon footprint as an indicator of unsustainable energy use is abated by 59 %. Overall, the HAD-DWC-VRC-PSD process is economically viable and eco-sustainable in a way.