As seen from Equation , the vapor-liquid equilibrium is predicted using Raoult's law, and the liquid-phase non-ideality accounted by the activity coefficients (γ i ) calculated using the UNIFAC Dortmund group-contribution method . y i and x i are the mole fractions of the i th component in the gas and liquid phase, respectively. N is the number of components, P Sat i (T ) is the saturation pressure at temperature T.