ABSTRACT
Binary distillation is a multistage process for separating a mixture of two components using the principles of vapor-liquid equilibria. Although binary distillation is not a very common occurrence in practice (impurities are normally present along with the two primary components to be separated), developing methods for solving it is beneficial in two ways. In the first place, binary distillation is helpful in representing the principles of distillation in general by using a simplified model. Second, many real-life distillation problems can be approximated by a binary system. The simplifying assumptions and the graphical techniques described in this chapter were necessary before the advent of computers and the fast and rigorous programs for solving columns. Why, then, bother with learning the simplified outdated methods? The graphical methods have the advantage of providing a qualitative, as well as quantitative, albeit perhaps approximate, representation of the problem. They allow the engineer to visualize the effects of the different variables and their feasible ranges before proceeding to the rigorous numerical solution. The simplified methods should not be used as a substitute but in conjunction with rigorous methods. Computer programs can, in fact, enhance the use of graphical techniques for evaluating column performance trends because the very same data needed to construct the diagrams are usually readily available from the simulation output.
