Effects of mixing rules on phase equilibrium calculations

The density dependence in the mixing rule of the cohesion parameter of the cubic equation of state is found not to be necessary in vapour—liquid equilibrium (VLE) calculations. The effects of the functional form and the number of the adjustable parameters of the mixing rules on VLE calculations are examined. It is found that the functional form is less influential in VLE calculations than the number of adjustable parameters and that two adjustable parameters in the mixing rules are sufficient for practical applications.