Industrial & Engineering Chemistry Research, Vol.43, No.14, 3908-3923, 2004
Shortcut design method for columns separating azeotropic mixtures
A shortcut method is proposed for the design of columns separating homogeneous azeotropic mixtures. Azeotropes are treated as pseudocomponents, and a C-component system with A azeotropes is treated as an enlarged (C + A)-component system. This enlarged system is divided into compartments, where each compartment behaves like a nonazeotropic distillation region formed by the singular points that appear in it. The compartment boundary is linearly approximated. A procedure is proposed for transforming vapor-liquid equilibrium behavior in terms of pure components into that in terms of singular points, allowing relative volatilities to be characterized in terms of singular points. The classical Fenske-Underwood-Gilliland method can then be used to design columns separating azeotropic mixtures. This method is extremely computationally efficient and can be applied to homogeneous azeotropic mixtures with any number of components. The results of the shortcut design method are useful for initializing rigorous simulations using commercial software.