Optimisation de procédés chimiques complexes: Etude d'un atelier de monochloration du benzène

Abstract

Several procedures for the computer aided design of complex plants involving chemical reactors, rectification columns and recycle streams are presented. In the first part, these cyclic processes are represented by a sequential, two-hierarchical-level tree. A “branch and bound” method is then used to find the optimal structure for given operating conditions. The synthesis of a benzene chlorination process with one or several reactors is used to illustrate the implementation of the algorithm. The structure and the operating conditions are both optimized in the second part of this work. By using structural parameters to represent physical unit connections within a superstructure, the problem becomes one of large-scale nonlinear programming (NLP). A projected reduced gradient algorithm, extended to nonlinear constrained problems, is used to solve the nonlinear program. The same example as was used in the first part shows the complementary nature of the two approaches, with the first one providing a good initial feasible point for the second.