Examinando por Autor "González, Miguel A."

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Experimental data and modeling of viscosities and densities of pyrene + toluene + heptane mixtures at T = (293.15 to 343.15) K
(Elsevier, 2023) Tenorio, Maria José; Suárez, Inmaculada; Díaz Magdaleno, Julia; González, Miguel A.; Coto, Baudilio
Oil mixtures are a complex system that remains unclear. Its study is particularly challenging due to the many variables involved in their properties. These include, for instance, the compositions of the mixture and the nature of their compounds. To simplify the study of these systems, it is proposed to model them with simpler mixtures, as in the case of using hydrocarbon mixtures to describe the behavior of crude oil. Two mixtures have been prepared; the one hand, a binary mixture of pyrene in toluene, and on the other hand, a ternary mixture of pyrene in toluene/heptane has been prepared. Their densities and dynamic and kinematic viscosities have been measured from (293.15 to 343.15) K at atmospheric pressure. The compositions of binary and ternary systems are 1.0, 2.5, 5.0, 7.5, 10.0, 12.5, and 15.0 % weight fraction of pyrene. In the case of ternary systems, several toluene/heptane mass ratios have been studied, from 0.1 to 10. This article presents new experimental results of density and viscosity for the mixtures studied. Therefore, a theoretical study has been carried out to describe experimental data. Viscosity models, such as Ideal, Refutas, Ratcliff, UNIFAC-Visco, and Krieger, have been checked and, in some cases, have been modified to analyze the dependence of viscosity on temperature, composition, and possible association of pyrene. Standard deviations for each model and system have been calculated. Modified Ratcliff and Krieger models presented an excellent agreement with experiments.
Viscosities and Densities of Binary and Ternary Mixtures of Aliphatic and Polyaromatic Hydrocarbons: Pyrene +1-Methylnaphthalene + Dodecane at T = (293.15 to 343.15) K. Experiment and Modeling
(American Chemical Society, 2024-03-18) Tenorio, María José; González, Miguel A.; Magdaleno, Julia D.; Suárez, Inmaculada; Coto, Baudilio
This work presents new experimental viscosity and density data for aromatic and polyaromatic compounds in binary and ternary pyrene, 1-methylnaphthalene, and dodecane mixtures. The lack of experimental viscosity data for these mixtures requires the development of a new database, which is vital for understanding the behavior of mixtures in more complex systems, such as asphaltenes and fuels. The mixtures proposed in this work have been measured over a temperature range of (293.15 to 343.15) K at atmospheric pressure. Several mixture compositions have been studied at these conditions: 1.0, 2.5, 5.0, 7.5, 10.0, 12.5, and 15.0% pyrene mass fraction. The concentration of pyrene correlates with an increase in the viscosity and density values. At the lowest temperature in binary mixtures, the corresponding values reach 4.4217 mPa·s for viscosity and 1.0447 × 103 kg·m–3 for density, respectively. In ternary mixtures, the introduction of dodecane leads to the lowest maximum values of 3.5555 mPa·s for viscosity and 1.0112 × 103 kg·m–3 for density at the same temperature. The experimental data have been employed for the specific modification of viscosity models. These modifications could facilitate the prediction of the viscosity of mixtures that are more complex than those presented in this work. Various viscosity models have been employed, such as Linear, Ratcliff and Khan, modified UNIFAC-Visco, and Krieger–Dougherty. The settings in the models used reliably reproduce the experiment reliably. However, the Ratcliff model agrees excellently with the experiment, having a low standard deviation (2.0%) compared to other models. Furthermore, a model based on the equation of state of Guo is proposed to predict the viscosity values by modifying the specific parameters and adjusting them to the mixtures proposed in this work. The results from this study are compared to previous work, where pyrene, toluene, and heptane mixtures were analyzed. In this case, we find that the decrease of aggregation grade in the present systems is predicted by the model fixed in this work.