“…Classical thermodynamics indicates that minimization of the Gibbs free energy is a natural approach for calculating the equilibrium state of a mixture. Most of the available methods for Gibbs free energy minimization in reactive mixtures have been proposed during the last two decades, and they include a variety of problem formulations and numerical techniques such as local search methods with and without decoupling strategies (Castillo and Grossmann, 1981;Castier et al, 1989;Xiao et al, 1989;Gupta et al, 1991;Perez-Cisneros et al, 1997;Stateva and Wakeham, 1997), branch-and-bound optimization methods (McDonaldand Floudas, 1996;McKinnon and Mongeau, 1998), algorithms using homotopy continuation (Jalali and Seader, 1999;Jalali et al, 2008), deterministic methods based on interval mathematics (Burgos-Solorzano et al, 2004) and stochastic optimization methods (Reynolds et al, 1997;Lee et al, 1999;Bonilla-Petriciolet et al, 2006;Bonilla-Petriciolet et al, 2008).…”