A GLOBAL MINLP APPROACH FOR PHASE-EQUILIBRIUM CALCULATIONS

The number, nature and composition of phases at physical equilibrium a re determined by minimizing Gibbs free energy. The existence of the ph ases is described by a set of binary variables which lead to the formu lation of a MINLP problem. The resolution of the initial MINLP problem leads to the resolution of Non Linear Programming subproblems which c ontain local extrema. We propose to determine the global optimum of ea ch NLP problem by the;se of a homotopy continuation method. This origi nal resolution is illustrated on a L-L-V equilibrium problem.