Liquid Densities of Xylene Isomers and 2-Methylnaphthalene at Temperatures to 523 K and Pressures to 265 MPa: Experimental Determination and Equation of State Modeling (original) (raw)
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Fluid Phase Equilibria, 2011
a b s t r a c t Experimental densities are reported for n-hexadecane, n-octadecane, and n-eicosane at pressures to ∼265 MPa and temperatures of 323.15, 423.15, and 523.15 K. The reported densities are in good agreement with the available literature data that cover limited pressure and temperature ranges. The Peng-Robinson equation of state (PR EOS), a new high-temperature high-pressure volume-translated Soave-Redlich-Kwong equation of state (HTHP-VT SRK EOS), and the perturbed-chain statistical associating fluid theory (PC-SAFT) are used to predict the reported densities. Both the HTHP-VT SRK and PC-SAFT equations exhibit mean absolute percent deviation (MAPD) values of 2.4-1.3% for the densities of all three hydrocarbons while the MAPD values for the PR EOS are all near 16%.
Journal of Molecular Liquids, 2011
Experimental densities of three groups of liquid organic substances (acids, esters, alcohols) have been correlated using Goharshadi-Morsali-Abbaspour (GMA) equation of state and then the values calculated from the equation of state have been compared with the experimental data. The paper reports new correlation for the density of 20 organic liquids (7 acids, 7 esters and 6 alcohols) at temperatures between 293.15 K and 393.15 K and pressures between 0.1 MPa and 35 MPa. A comparison with experimental data in the specified range of temperature from low to high pressures has been made. Some generalized correlations are also used for comparison with GMA equation of state and experimental data. The results show that the equation of state reproduces the experimental PρT data of liquid organic compounds with good accuracy. The excellent agreement with experimental data indicates that this equation of state can be used to calculate the density of liquid organic compounds with a high degree of certainty. The comparison with other correlations shows that the GMA equation of state is better to some extent and reliable in the given temperature and pressure range.
The Journal of Chemical Thermodynamics, 2014
New data of high pressure density have been reported for p-xylene pure component and its binary mixtures with dimethyl carbonate, diethyl carbonate, n-octane and n-decane at (288.15, 298.15 and 308.15) K and (0.1, 5, 10, 20, 30 and 40) MPa and they have been compared with those available in the literature. The high pressure density has been correlated and predicted using a modified Tait equation and Nitta Chao group contribution model respectively. The derived thermophysical properties such as isothermal compressibility (j T ), isobaric thermal expansivity (a P ) and internal pressure (p) have been also calculated.
The Journal of Supercritical Fluids, 2013
The high pressure vapor-liquid equilibria of binary mixtures of propylene and isopropyl alcohol were measured experimentally within a temperature range of 315-440 K and pressures up to 6 MPa, using a synthetic method. The experimental data were modeled using the cubic plus association (CPA) equation of state (EoS) by once considering and once not considering solvation between the inert and polar molecules in the mixture. Results indicated that taking solvation into account did not make a huge improvement in the accuracy of CPA for this particular system. In addition, the Soave-Redlich-Kwong (SRK) EoS, representing the widely-used engineering EoS family, was also compared to the CPA. Results showed that both the CPA and SRK perform well for this system in the pressure and temperature range investigated, however, the values of binary interaction coefficients required by SRK to approach the experimental data are much greater than for CPA.
Vapor−Liquid Equilibria Data for Binary Systems of Ethylbenzene + Xylene Isomers at 100.65 kPa
Journal of Chemical and Engineering Data, 2005
Vapor-liquid equilibria data for binary mixture of ethylbenzene + xylene isomers were obtained isobarically with a modified Fischer cell at 100.65 kPa. Temperatures were measured with a resolution of (0.001 K, and vapor-and liquid-phase compositions were analyzed with a gas chromatograph. The data obtained were considered to be thermodynamically consistent according to the Van Ness and Fredenslund test. Pure vapor pressures for the compounds are also reported. Interaction parameters for the most used activity coefficient models and cubic equations were obtained through data fitting performed with Aspen Plus 10.1.
Equation of state modeling of high-pressure, high-temperature hydrocarbon density data
The Journal of Supercritical Fluids, 2010
Experimental densities are reported for n-pentane, n-octane, cyclooctane, 2,2,4-trimethylpentane, ndecane, and toluene to ∼280 MPa and ∼250 • C. These densities are in good agreement with available literature data that typically cover lower pressure and temperature ranges than those reported here. The data are modeled with the Peng-Robinson (PR) and Soave-Redlich-Kwong (SRK) cubic equations, the temperature-dependent, volume-translated SRK equation, the temperature-and density-dependent SRK equation, and the SAFT and PC-SAFT equations. Mean absolute percentage deviation (MAPD) values between densities calculated with the PR equation and literature data are 4.55 for n-pentane, 2.91 for n-octane, 3.68 for cyclooctane, 3.98 for 2,2,4-trimethylpentane, 5.58 for n-decane, and 1.99 for toluene. With the exception of 2,2,4-trimethylpentane, these MAPD values are substantially better than those obtained with the SRK and modified SRK equations. Although both SAFT-based models have MAPD values significantly lower than those with the PR equation, the PC-SAFT equation provides the lowest MAPD values.
Fluid Phase Equilibria, 2007
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.
Journal of the Serbian Chemical Society, 2015
Densities data of n-hexane, toluene and dichloromethane at temperatures 288.15-413.15 K and at pressures 0.1-60 MPa, determined in our previous work, were fitted to the modified Tait equation of state. The fitted temperature-pressure dependent density data were used to calculate the derived properties: the isothermal compressibility, the isobaric thermal expansivity, the difference between specific heat capacity at constant pressure and at constant volume and the internal pressure, over the entire temperature and pressure intervals specified above. In order to assess the proposed modeling procedure, a comparison of the obtained values for the isothermal compressibility and the isobaric thermal expansivity with the corresponding literature data were performed. The average absolute percentage deviations for isothermal compressibility were: for n-hexane 2.01-3.64%, for toluene 0.64-2.48% and for dichloromethane 1.81-3.20%; for the isobaric thermal expansivity: for n-hexane 1.31-4.17%, ...
Journal of Chemical & Engineering Data, 2011
This paper presents experimental liquid densities for n-pentane, n-octane, and n-nonane and their binary mixtures from (273.15 to 363.15) K over the entire composition range (for the mixtures) at atmospheric pressure. The experimental apparatus is a vibrating-tube densimeter. It is possible to compare the results to a generalized correlation for liquid densities of n-alkanes and to molecular dynamics simulations. The average absolute percentage deviation is (0.06 and 0.8) % using the equation and the simulation results.