Calculation of homogeneous azeotropes in reactive and non-reactive mixtures using a stochastic optimization approach

In this paper we introduce an alternative strategy to find homogeneous azeotropes in reactive and non-reactive mixtures which is based upon the Simulated Annealing optimization technique. This stochastic optimization method is used to robustly solve a system of non-linear equations that results from the equalities of the orthogonal derivatives of the Gibbs energy and the Gibbs energy of mixing in the vapor and the liquid phases. For non-reactive systems, this equation system is solved by considering conventional composition variables while for reactive cases we use the transformed composition variables proposed by Ung and Doherty. Numerical performance of our approach is illustrated using several examples previously reported in the literature and results show that it is a suitable and robust strategy for the calculation of homogeneous azeotropes in mixtures with or without chemical reactions. (C) 2009 Elsevier B.V. All rights reserved.