Representation of residue curve maps with Pinch Zones

Abstract

Nowadays, the residue curve maps are one of the best tools used to check the feasible alternatives for complicated separation systems such as the non ideal multicomponent distillation systems. However, in order to compare the different possibilities that come up from the analysis of the residue curve map, it would be required to complete the information with an idea of the number of stages required. The main limitation of the residue curve maps is that the pinch zones are not detected. One system that can be feasible from the residue curve map analysis can be actually technically unfeasible because it is running over a pinch zone that would require a large number of stages. This paper addresses this fact by representing the pinch zones on the residue curve map and providing a first evaluation of the number of stages that will be required according to the inverse of the modulus of the vector between the vapor and liquid composition. The modulus can be applied to systems of any number of components. Some examples are used to illustrate the main guidelines regarding the use of the y-x modulus graphics. The Software Simulis Thermodynamics on Matlab is used for the representation of residue curve maps with pinch zones.