1. A method for controlling a separator or a refiner, comprising: recording existing binary phase equilibrium data; implementing a computer-based method for predicting binary phase equilibrium data comprising: by using binary phase equilibrium measurement data, calculating an index X of proximity ratio to critical points according to X = p 1 ⁢ s + p 2 ⁢ s P c ⁢ ⁢ 1 + p 2 ⁢ s , and calculating infinite dilution pressure gradients Y 1 and Y 2 according to: Y 1 = γ 1 ∞ ⁢ p 1 ⁢ s - p 2 ⁢ ⁢ s P c ⁢ ⁢ 1 - p 2 ⁢ s ⁢ ⁢ and ⁢ ⁢ Y 2 = p 1 ⁢ s - γ 2 ∞ ⁢ p 2 ⁢ s P c ⁢ ⁢ 1 - p 2 ⁢ s , wherein P c1 represents a critical pressure of a lighter component in a binary system, p 1s and p 2s represent vapor pressures of components 1 and 2, respectively, at a temperature T, and γ i ∞ and γ 2 ∞ represent infinite dilution activity coefficients of components 1 and 2 in a liquid phase, respectively; correlating the obtained index X of proximity ratio to critical points with the infinite dilution pressure gradients Y 1 and Y 2 and calculating infinite dilution activity coefficients γ 1 ∞ and γ 2 ∞ or binary parameters A and B from the X-Y 1 correlation and the X-Y 2 correlation, respectively, the binary parameters A and B being given by A=ln γ 1 ∞ and B=ln γ 2 ∞ ; and evaluating thermodynamic consistency of the X-Y 1 and X-Y 2 correlation data according to H =  β e ⁢ ⁢ x ⁢ ⁢ p - β ca ⁢ ⁢ l β ca ⁢ ⁢ l  using values of β exp and β cal obtained by incorporating values of binary parameters A and B into the following equation β = F  B - A  to determine the correlations by confirming that data that satisfy the thermodynamic consistency within a predetermined error range is highly reliable data, and correlating X with Y 1 and Y 2 using only thermodynamically consistent data, wherein β exp represents a value of β that is calculated according to F/|B−A| using F, A, and B determined from actually measured values; β cal represents a value of β that is calculated from F  B - A  = aP b using values of a and b obtained by correlation of actually measured values: A and B represent binary parameters; F represents deviation from A=B in a one-parameter Margules equation; P represents a pressure or an average vapor pressure; a and b represent constants specific for a binary system; and predicting new binary phase equilibrium data using the calculated values of the infinite dilution activity coefficients γ 1 ∞ and γ 2 ∞ or binary parameters A and B; and controlling the separator or the refiner according to the predicted new binary phase equilibrium data.