Automatic generation of global phase equilibrium diagrams for binary systems from equations of state

Abstract

An automated and reliable procedure for systematic generation of global phase equilibrium diagrams (GPED) for binary systems is proposed. The approach utilizes equation of state, incorporates solid phase and is successful in generation of type VI phase diagram. The procedure enables automatic generation of GPED which incorporates calculations of all important landmarks such as critical endpoints ( CEP), quadruple point ( QP, if any), critical azeotropic points ( CAP), azeotropic endpoints ( AEP), pure azeotropic points ( PAP), critical line, liquid–liquid–vapor line ( L 1 L 2 V, if any), solid–liquid–liquid line ( SL 1 L 2, if any), solid–liquid–vapor line ( SLV) and azeotropic line. The proposed strategy is completely general in that it does not require any knowledge about the type of phase diagram and can be applied to any pressure explicit equation of state model. The overall methodology include predictor-corrector method for line tracing, homotopy continuation for critical point calculations and phase stability test, automatic differentiation to calculate derivatives and trust region dogleg approach to compute thermodynamic landmark such as critical endpoints and quadruple points.