DEQ - Departamento de Engenharia Química

URI Permanente desta comunidadehttps://repositorio.ufrn.br/handle/1/133

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High-pressure density measurements for the binary system cyclohexane + n-Hexadecane in the temperature range of (318.15 to 413.15) K
(ACS Publications, 2007-02-13) Chiavone Filho, Osvaldo; Amorim, Josinira Antunes de; Paredes, Márcio Luís Lyra; Rajagopal, Krishnaswamy
The densities of binary mixtures of n-hexadecane and cyclohexane at high pressures were measured in the range of (6.895 to 62.053) MPa at six different temperatures varying from (318.15 to 413.15) K and for eight compositions. The measurements were made by a high-pressure Anton Paar DMA 512 P densimeter integrated with the Ruska 2370 mercury Free PVT System. The densimeter was calibrated using analytical grade toluene, cyclohexane, and n-heptane as calibration fluids. The experimental error of density measurements is estimated as 0.5 kg‚m-3. The measured densities at 348.15 K agree well with the available literature values at different pressures. The excess volumes, thermal expansion, and isothermal compressibility coefficients were obtained from measured densities. All data were correlated successfully with a modified Peng-Robinson equation of state
Modeling high-pressure densities at wide temperature range with volume scaling: Cyclohexane + n-hexadecane mixtures
(Elsevier, 2007-10-01) Chiavone Filho, Osvaldo; Amorim, Josinira Antunes de; Paredes, Márcio Luís Lyra; Rajagopal, Krishnaswamy
High-pressure density data for cyclohexane + n-hexadecane mixtures at a wide temperature range was modeled with several classical equations of state (EOS) and correlative models. A modification for softening the co-volume and another for a volume scaling of the Peng–Robinson EOS (VS-PR) were proposed. The VS-PR model is able to correlate the pure component experimental data employing only five adjustable parameters, with root-mean-square deviation (RMSD) between calculated and experimental densities essentially within the experimental error. This result is superior to widely used approaches, i.e., a six parameter Tait model and six parameter volume translations (temperature and pressure dependent) for Peng–Robinson and Patel–Teja EOS. The VS-PR model also represents well the isobaric thermal expansion and the isothermal compressibility coefficients of the pure cyclohexane, a small naphthenic substance as well as a long chain n-alkane hydrocarbon, n-hexadecane. When modeling the mixture data, the use of VS-PR model of pure components along with the Redlich–Kister expansion, truncated at the first term, the density was correlated within a RMSD only 60% greater than the experimental error. The proposed model is able to accurately represent all the tested mixture data with a relatively small number of parameters

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