Avaliação de modelos termodinâmicos de tensão interfacial em substâncias puras e misturas

Abstract

Interfacial tension is a relevant themophysical property in compound separation processes, especially in liquid-liquid and liquid-gas systems. Its origin comes from an unbalance at intermolecular interactions level, which causes unequal forces in the interfacial region. This property is essential for the processing of petroleum components, which makes this research relevant to the process of phase separation present in the production of oil and natural gas. In this work, some thermodynamic models for the prediction of interfacial tension in liquid-liquid and liquid-gas systems were evaluated, for the pure substances water, ethanol, propan-1-ol, carbon dioxide, n-pentane, n-hexane, toluene, n-heptane, n-octane and n-decane, and for aqueous mixtures of propan-1-ol and methyl acetate. For pure substances, the models of Macleod-Sugden (1923-1924); Brock and Bird (1955); Curl and Pitzer (1958 – 1995); Sastri and Rao (1995) and Zuo and Stenby (1997) were evaluated. For aqueous mixtures with an organic fraction, the model of Meissner and Michaels (1949) was evaluated. Based on the results obtained in this work, it can be concluded that the most suitable correlations for hydrocarbons are those of Zuo and Stenby (1997) and Brock and Bird (1955). However, for alcoholic components, the most adequate models are those of Sastri and Rao (1995) and Macleod-Sugden (1923-1924). The Meissner and Michaels (1949) model presented good results for aqueous solution of methyl acetate with molar concentrations below 10%, with an average error of -2,038 ± 1,459%.