THERMODYNAMIC PROCESS CONTROL BASED ON PSEUDO-DENSITY ROOT FOR EQUATION OF STATE

A thermodynamic modeling system comprising a computer, a thermodynamic process simulation application, and a thermodynamic equation of state application is provided. The thermodynamic equation of state application determines a density root based on a first and second point of departure from an equation of state and based on a first and a second extrapolation equation. The first departure point satisfies the equation the partial derivative of pressure with respect to density equals a first constant times the pressure divided by the density plus a second constant. The density root is determined as a pseudo-density in a phase two when the specified pressure is greater than the second departure point pressure and in a phase one when the specified pressure is less than the first departure point pressure. The thermodynamic process simulation application invokes the thermodynamic equation of state application to determine a result based on the density root.