Key words: supercritical fluids, chemical and phase equilibria, phase diagrams, critical point, multicomponent mixture, non-ideality, thermophysical behaviors, monoterpenes, a-pinene, heteroazeotrops, mathematical modeling
The mathematical and calculating models were developed to solute the specific research problems on thermodynamics of multicomponent and multiphase mixtures. The features of chemical and phase equilibria were examined both for the ideal-gas approximation and the non-ideality. The conditions of equilibrium phase stability were studied for multi phase systems. The calculation results of specific phase diagrams, binodal and spinodal are demonstrated for the appropriate reaction mixtures. The new interpretation of mathematical model was suggested for the localization of critical point, especially for fixed multicomponent chemical mixtures. The new variation of classical homotopy method was developed for the soluting of complex nonlinear equations systems, which are the princi ples of concerned mathematical models. The some anomalous phase profiles and the critical curves were analyzed to demonstrate the necessity of taking into account the pointed features at the planning of experiments, the reactor parameters calculations. The examples of specific multicomponent non-ideal mixtures indicate the possibility of thermodynamic and thermophysical behaviors calculations (entropy, enthalpy and heat capacity; thermal reaction effect, adiabatic warming up). It was noted that the cubic state equations are quite suitable for the prediction of property deviations from the ideal-gas state and can be used for the prognosis of behavior anomaly at the critical point surrounding.
doi:10.1134/S1990793109070033