Premium
Computation of tricritical points in ternary systems
Author(s) -
Kohse Bruce F.,
Heidemann Robert A.
Publication year - 1993
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690390714
Subject(s) - tricritical point , ternary operation , thermodynamics , equation of state , phase diagram , binary number , computation , phase (matter) , series (stratigraphy) , mathematics , statistical physics , physics , computer science , algorithm , quantum mechanics , paleontology , arithmetic , biology , programming language
At tricritical points, four equations in the thermodynamic variables must be satisfied. Methods of evaluating the functions and solving these four equations have recently been developed (Michelsen and Heidemann, 1988). A modified approach to the evaluation of these functions and a new solution procedure for the calculation of tricritical points in equation of state models are presented here. The new solution procedure is evaluated in comparison to previous ones, and its application is made using the Peng‐Robinson and Soave‐Redlich‐Kwong equations of state. The new procedure proved capable of locating tricritical points in a variety of systems with complex multiphase behavior. These included ternary systems with single tricritical points, systems with an ordinary critical point occurring at the same composition as a tricritical point and systems capable of four‐phase equilibria with two tricritical points. Comparisons are made with experimental tricritical data for eight systems. The calculations prove to be highly sensitive to pure component and binary parameters in the equation of state models. Features of phase diagrams for tricritical mixtures are discussed as well as the predictions of tricritical points in several homologous series of ternary systems.