Computation and modeling of tricritical phenomena in ternary and quaternary mixtures using the Perturbed Chain—Statistical Associating Fluid Theory equation of state

摘要: Tricritical points (TCPs), contained in two-phase holes three-phase surfaces, are of great importance industrial applications near-critical and supercritical technology because they occur a range temperatures, pressures compositions where the technological processes carried out. Their predictions also important for mapping transitions between different types fluid phase behavior, when using molecular parameters theoretical thermodynamic models, since these take into account interactions transition. In ternary systems, tricritical point (TCP) has zero degrees freedom; other words, it exists only at unique condition pressure, temperature composition. On hand, quaternary state one degree freedom, line may exist. this work, procedure was developed implemented theoretical, non-cubic Perturbed Chain-Statistical Associating Fluid Theory (PC-SAFT) equation (EoS) computing predicting various systems with single points, lines (involving n-alkanes, branched alkenes, alcohols, water, carbon dioxide, nitrogen hydrogen sulfide) without fitting binary interaction parameter. The results were compared experimental data obtained from literature an excellent agreement within temperatures practical interest engineering.