AN APPLICATION OF THE ERROR-IN-VARIABLES MODEL PARAMETER-ESTIMATION FROM VAN NESS-TYPE VAPOR-LIQUID-EQUILIBRIUM EXPERIMENTS

The Error-in-Variables Model (EVM) provides a means for estimating parameter values in mathematical models where there is error in every measured variable. This is a distinct improvement over the Method of Least Squares in most situations because the latter requires that there be error in measuring only one of the variables. As an example of the use of EVM, a method is presented for estimating Wilson equation parameters in binary and ternary vapor-liquid equilibrium where the data are obtained using the Van Ness experimental technique. The application presents unusual difficulties in that the compositions of the phases are not measured directly and the total quantity of one component is only measured as the sum of a series of increments.