Development of an Equation of State for the Representation of Solid-Liquid, Solid-Vapour, and Liquid-Vapour Equilibria of Substances of Interest for the Air Distillation Process

摘要

A common problem in the industrial cryogenic processes, as cryogenic air distillation, is the solidification ofrnsome impurities. Consequently, a thermodynamic model suitable for being applied in the simulation ofrncryogenic processes should account for the solid-fluid equilibrium. The capability of the Yokozeki equationrnof state in representing phase equilibrium experimental values of pure compounds has been verified. Somernlimits have been found with respect to the solid-liquid equilibrium. In order to overcome these limits thernSolid Liquid Vapour Peng-Robinson equation of state (SLV PR EoS) has been proposed. A comparisonrnbetween the SLV PR EoS and the experimental values has been presented for nitrogen, oxygen, argon,rnkrypton, xenon, neon, carbon dioxide, nitrous oxide, methane, ethane, ethylene, propane and propylene, andrna good agreement has been found. Furthermore, the equation proposed has been used for representing thernphase equilibria of the binary mixtures methane-carbon dioxide and ethane-carbon dioxide.