Homotopy continuation method for calculating critical loci of binary mixtures

This work describes an algorithm that uses the Heidemann and Khalil (1980, A.I.Ch.E. J., 26, 769-779) critical point criteria and a homotopy continuat ion technique for calculating critical loci in binary mixtures. This approa ch is able to track smoothly transition from G/L critical points to L/L cri tical points without the need of changing initial estimates. Such transitio ns marked by the existence of a turning point in the critical locus are com monly found in type III and IV mixtures. The tangent plane global stability tests are included to locate UCEPs and LCEPs which are intersections of th e critical locus and the LLG line. The continuation method is as efficient as a gradient-based approach like Heidemann and Khalil's method and as robu st as the Hicks and Young's grid-search approach. It also provides physical insight to the change in phase behavior as the composition and the equatio n of states parameters change. (C) 1999 Elsevier Science Ltd. All rights re served.