Energy-efficient design of extraction-distillation process for 2,2,3,3-tetrafluoro-1-propanol/water separation with thermodynamically verified liquid-liquid and vapor-liquid equilibrium behaviors

Abstract

Design of 2,2,3,3-tetrafluoro-1-propanol (TFP)/water separation process by energy-saving hybrid extraction-distillation system is investigated in this paper. Solvent extraction is one of the most promising energy-efficient separation methods because the major part of this separation is achieved through an extraction column without needing of reboiler duty. Thus, by utilizing a hybrid extraction-distillation separation process, huge economic potential can be realized with an important prerequisite of finding an effective solvent for the liquid-liquid separation. In this work, an efficient solvent of diisopropyl ether (DIPE) is found for this separation process. The thermodynamic model used in the investigation not only satisfies the experimental data of ternary liquid-liquid equilibrium, but also predicts well the behavior of binary vapour-liquid equilibrium, showing the credibility of simulation study. Another important aspect of this paper is to also consider the way to achieve a minimum density difference of liquid-liquid extraction in the analysis. It is found that the proposed extraction-distillation system by utilizing DIPE as solvent not only can achieve over 100 kg/m3 density difference in the extraction column, but also can significantly reduce total annual cost by 51.1%, as compared to that of a heterogeneous dividing-wall column system recently published in open literature.