Polynomial Objective Functions for Flash Calculations: Binary, Ternary, and Quaternary Systems

Polynomial objective functions are developed for the vapor fraction in vapor-liquid equilibrium flash calculations for binary, ternary, and quaternary systems. The form of the polynomial suggests possible expansion to N-component systems. An extensive testing of these objective functions was performed using experimental data for binary systems. Comparative analysis with traditional Rachford-Rice objective function demonstrates better predictive capability and improved computational strategy for the new form. Comparison between predictions and experimental data shows a good match, even for cases where the Rachford-Rice objective function fails to yield realistic results.