Generalised closed double-column system for batch heteroazeotropic distillation

We study the separation of the minimum homoazeotropic mixture isopropanol–water by applying cyclohexane and n-hexane as entrainer in a new Generalised Double-Column batch heteroazeotropic distillation System (GDCS). This configuration has three further operation parameters to the original Double-Column System (DCS; Denes et al. (2009) [1]). They give the possibility of a more efficient operation like that of the DCS.First the feasibility of the new configuration is studied by a simplified method then the effect of the new operational parameters is determined by rigorous simulation. After that the minimum operational time is determined for the GDCS and for the original DCS and their performance is compared (operational time, specific energy demand of the products). The above investigations are done for three different charge compositions. The comparison is done in the cases of both entrainers.The GDCS proved to be feasible. The study of the effect of the new operational parameters makes clear the choice of their values. Due to its higher degrees of freedom the GDCS provides a more flexible operation than the DCS. By the GDCS, in every case studied, we obtained shorter duration and lower specific energy demand.Finally the performances of the two entrainers are compared on the basis of VLLE conditions and of the simulation results.