(378b) A Proposal on Thermodynamic Consistency Test of Vapor-Liquid Equilibria Data at High Pressure

The consistency test of vapor-liquid equilibria is useful for discussing the quality of experimental data. For normal pressures, many research works have been made using point test and area test. The authors have discussed for binary vapor-liquid equilibria of 474 systems and 1,056 data sets [1, 2]. However, the research work for high-pressure vapor-liquid equilibria is quite few [3, 4].

This paper deals with the proposal of consistncy test of high-pressure vapor-liquid equilibria. The point test and area test at high pressure have been discussed from the relationship to consistency test at normal pressure. Firstly, the point test has been discussed using the Peng-Robinson, MHV1, MHV2 and NRTL models for 9 binary systems composed of CO₂ and solvent [5-7]. The judge criterion is fixed by relative deviations for total pressure (less than 5 %) and vapor-composition (less than 0.010 mole fraction). Secondly, the area test has been proposed using activity coefficients by thermodynamic equations [3] for 15 binary systems composed of ethane + solvent and CO₂ + solvent. The judge criterion is fixed by equation from Gibbs-Duhem equation (100x∫ln(γ₁/γ₂)dx < 3).

References

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[7] H. Matsuda, T. Suga, T. Tsuji, K. Tochigi, K. Kurihara, A. K. Nelson and C. McCabe: Fluid Phase Equilibria, 526, 112814 (2020)