Design and minimum reflux for heterogeneous azeotropic distillation columns

Abstract

A simple design technique for heterogeneous distillation columns has been developed. The underlying geometric conditions which govern minimum reflux are shown to share certain common features with homogeneous distillations, but differ in some important respects. It is shown that heterogeneous columns display some unusual sensitivities to the design parameters. The most notable being the drastic swings in the composition and temperature profiles with very small changes in the level of trace impurities in the product stream.

Shortcut methods for nonideal multicomponent distillation: 3. Extractive distillation columns

“…A good example is the purification of a binary alcohol-water mixture, which can be achieved by heteroazeotropic distillation using a heterogeneous entrainer (Pham et al, 1989;Urdaneta et al, 2002), extractive distillation using a homogeneous entrainer (Black, 1980), or by using a hybrid membrane-distillation configuration (Bausa and Marquardt, 2000). For both the homogeneous and the heterogeneous azeotropic distillation processes the choice of the entrainer, usually from a list of potential candidates, defines the structure of the process and is crucial to the economic performance.…”

Shortcut-based design of multicomponent heteroazeotropic distillation

“…Hence, there are very few publications on shortcut methods for heterogeneous distillation systems. Most of them consider immiscibilities only in the decanter (Pham et al, 1989;Wasylkiewicz, 1999). This practice, however, leads to the disregard of promising designs or miscalculations of the MED in many instances (Urdaneta et al, 2002).…”

“…The overall mass balance around the column and the decanter is therefore able to cross the distillation boundary in a feasible heteroazeotropic separation. Pham et al (1989) have extended the BVM to heteroazeotropic distillation but only consider designs with homogeneous column trays. The example separation in this work 1, however, requires some rectifying trays in the heterogeneous region to produce a feasible design.…”

Conceptual Design of Azeotropic Distillation Processes

“…The BVM can be applied to determine the MED of a heteroazeotropic distillation column if a decanter model is simply added [113]. In contrast to simple distillation columns, the rectifying section profile has to be calculated starting from the liquid composition of the reflux leaving the decanter to the top stage of the column and not from the top product.…”