(181au) Using an Integration Technique to Trace Coexistence Curves: Applications to Multi-Component Phase Equilibrium

Process simulation is an important tool in the design, development, analysis and optimization of technical processes. The simulation work, performed on computers, is mainly applied to chemical plants, chemical and petroleum engineering processes. Thermodynamic computations in process simulation, both in the field of physical properties and of phase equilibria, consumes about 60 to 80% of the computer time of which phase equilibrium calculations take up about 75% of the time. Phase equilibrium calculations mostly make use of conventional root finding algorithms. Hence, the development of faster and more efficient algorithms for thermodynamic computations becomes highly essential. To this end, a technique known as the Integrate method has been developed that involves the differential form of the equilibrium constraints.  These relationships are solved using numerical integration techniques and have been shown to produce results that both take less time (than the root-finding technique) and are of useful accuracy.  In the current study, we evaluate the method for use in VLE and LLE for a variety of equations of state, from van der Waals to SAFT.