Cubic equation of state for calculation of phase equilibria in association systems

Chemical potential of an associating component is derived from cubic equation of state. It is separated in the rigorous way into effective physical part and excess of chemical contribution. The both parts of the chemical potential are given in form of explicit expressions, which does not need any cumbersome integration or differentiation. The simple expression for association equilibrium is derived. It depends only on repulsive term of EOS. The proposed method is applied for correlating VLE equilibria in binary mixtures and for prediction of pressure in ternary mixtures on basis of the constituent binary VLE data.