Collect. Czech. Chem. Commun. 1985, 50, 1-22

The DAN method for calculation of vapour-liquid equilibria using an equation of state; Bubble and dew point calculations

Josef P. Nováka, Vlastimil Růžička, Jr.a, Anatol Malijevskýa, Jaroslav Matouša and Jan Linekb

a Department of Physical Chemistry, Prague Institute of Chemical Technology, 166 28 Prague 6
b Institute of Chemical Process Fundamentals, Czechoslovak Academy of Sciences, 165 02 Prague 6-Suchdol


A modification of the computational technique for calculating bubble and dew points using an equation of state has been proposed. The procedure consists in the Double Application of the Newton-Raphson method (DAN) to the set of equilibrium conditions. The algorithm is very effective as it provides both values of equilibrium variables and a very qualified first estimate of the next equilibrium point. This enables to proceed along the phase envelope rather quickly and to achieve convergence within a few iterations except in the close vicinity of the critical point.