Estimation d’énergies de GIBBS de solvatation pour les modèles cinétiques d’auto-oxydation : développement d’une banque de données étendue et recherche d’équations d’état cubiques et SAFT adaptées à leur prédiction

Abstract : Liquid phase oxidation of hydrocarbons (also called autoxidation) is central to a large number of processes in the petrochemical industry as it plays a key role in the conversion of petroleum feedstock into valuable organic chemicals. This phenomenon is also crucial in oxidation-stability studies of fuels and its derivatives (aging). These liquid-phase oxidation reactions entail radical mechanisms involving more than thousands of compounds and elementary reactions. Kinetic modelling of these kinds of reactions remains a significant challenge because it requires thermodynamic and kinetic parameters, which are not abundant in literature. The EXGAS software, developed at LRGP, is able to generate these kinds of models but only for oxidation reactions taking place in a gaseous phase. It is assumed that the nature of elementary reactions in the liquid and gaseous phases is the same. The unique need to transfer a kinetic mechanism from a gas phase to a liquid phase is to update kinetic rate constant values and equilibrium constant values (called thermokinetic constants) of mechanism reactions. Therefore, in the framework of this PhD thesis, a new method aimed at applying a correction term to thermokinetic constants of gaseous phases is proposed in order to obtain constants usable to describe liquid-phase mechanisms. This correction involves a quantity called partial molar solvation GIBBS energy. An analysis of the precise definition of this property led us to conclude that it can be simply expressed as a function of fugacity coefficients and liquid molar density. As a result, this property could also be expressed with respect to measurable thermodynamic quantities as activity coefficients or HENRY’s law constants. By combining all the experimental data related to these measurable properties that can be found in the literature, it was possible to develop a comprehensive databank of partial molar solvation GIBBS energies (called the CompSol database). This database was used to validate the use of the UMR-PRU equation of state to predict solvation quantities. Moreover, the bases of a new parameterization for SAFT-type equations of state were laid. It consists in estimating pure-component parameters of SAFT-like equation using a very simple, reproducible and transparent path for non-associating pure components. This equation was used to calculate partial molar GIBBS energy of solvation of pure and mixed solutes. Last, equations of state were combined with EXGAS software to model the oxidation of n-butane in the liquid phase.
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Theses
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http://docnum.univ-lorraine.fr/ulprive/DDOC_T_2018_0295_MOINE.pdf
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https://hal.univ-lorraine.fr/tel-02130150
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Submitted on : Wednesday, May 15, 2019 - 3:49:43 PM
Last modification on : Thursday, May 16, 2019 - 1:35:51 AM

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Edouard Moine. Estimation d’énergies de GIBBS de solvatation pour les modèles cinétiques d’auto-oxydation : développement d’une banque de données étendue et recherche d’équations d’état cubiques et SAFT adaptées à leur prédiction. Génie des procédés. Université de Lorraine, 2018. Français. ⟨NNT : 2018LORR0295⟩. ⟨tel-02130150⟩

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