The GOP Approach in Phase and Chemical Equilibrium Problems

Abstract

This chapter introduces the reader to the global optimization of phase and chemical reaction equilibrium problems through the GOP algorithm studied by McDonald and Floudas (1994), (1995a), and (1995b). Two main classes of phase and chemical equilibrium problems are addressed: (a) the minimization of the Gibbs free energy and (b) the tangent plane stability criterion. Section 6.1 presents the formulation of minimization of the Gibbs free energy problem. Section 6.2 introduces the theoretical analysis for the application of the GOP approach using the NRTL activity coefficient model. Section 6.3 presents an illustrative example and a difficult phase equilibrium problem. Section 6.4 introduces the reader to the tangent plane stability problem and its mathematical formulation. Section 6.5 discusses the theoretical developments for applying the GOP to the tangent plane stability criterion, and finally section 6.6 presents an illustrative example.