Chemical and Biomolecular Engineering Research and Publications


Date of this Version



This paper was published in the Journal of “Fluid Phase Equilibria” Volume 232 and Issue 1- 2 on 25 October 2005, pages 48-45. And all the copy rights © of this paper belong to Elsevier B.V. and any other information about this paper can be found at Journal of Fluid Phase EquiliBria


The Gibbs energy minimization using activity coefficient models and nonlinear equation solution techniques are commonly applied for phase stability problems. However, dependence on the initial estimates and multiple solutions for these highly nonlinear equations are common drawbacks for some of the conventional approaches. We have used interval Newton method with the local composition model of NRTL for the phase stability analysis of 10 binary systems and 2 ternary systems at various feed compositions to locate all the stationary points. Results indicate that the interval Newton method is reliable and efficient.