Determination of Necessary Tray Numbers at Heteroazeotropic and Heteroextractive Distillation

Determination of Necessary Tray Numbers at Heteroazeotropic and Heteroextractive Distillation 

It is necessary to solve the questions of optimal arrangement and of optimal sequence for each particular mixture by means of conduction of calculation investigations. At this stage, there is a necessity for participation of a specialist possessing software for calculation of necessary tray numbers. This software should guarantee the determination of necessary tray numbers in sections, the determination of the best conditions of refluxing (reflux with one or two phases at their optimal correlation) and the determination of the best number of sections. 

Questions of optimal designing of heteroazeotropic distillation units were discussed in the works (Bril et al, 1974 Bril et al., 1975 Bril et al., 1977 Bril et al, 1985 Ryan Doherty, 1989 Pham Doherty, 1990a Pham Doherty, 1990b Pham Doherty, 1990c). 

The preliminary stage of design - collection of experimental data on phase equlibrium liquid-vapour (VLB) and liquid-liquid (LLE) for binary and ternary constituents of the mixture under separation and creation of adequate model on this basis - is of great importance for heteroazeotropic mixtures. 

Works of a number of investigators have shown that usage of data only on binary VLE does not create an adequate model that would satisfactorily describe the conditions at heteroazeotropic or heteroextractive distillation. The same can be said of the usage of data only on ternary LLE. 

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