Thermodynamic Characterization of Undefined Petroleum Fractions using Group Contribution Methods

Abstract

Properties of petroleum fractions of unknown composition, the so-called undefined petroleum fractions, are estimated using an approach based on group contribution methods. Using liquid density and molecular weight as experimental data and classical thermodynamics as framework, functional groups were assigned to each undefined fraction by minimizing its free energy. Thus, methods requiring molecular structures were used directly in phase equilibrium simulations of petroleum fluids. The proposed procedure also allows the critical properties of such undefined fractions to be calculated employing no specific correlations. The obtained results show reasonable accuracy concerning phase equilibrium experiments.

Hydrogen Solubility in Heavy Undefined Petroleum Fractions Using Group Contributions Methods

“…These properties are frequently calculated from correlations (Firoozabadi, 1988;Lee and Kesler, 1975;Pedersen et al, 2004), but they do not always lead to the same results, because each one was developed for different sets of fluids at limited conditions. Thus, recently, group contribution methods have been recently extended to pseudocomponents, showing a good performance (Carreón-Calderón et al, 2012;Xu et al, 2015). Carreón-Calderón et al (2012) presented a new characterization procedure based on group contribution methods.…”

“…Thus, recently, group contribution methods have been recently extended to pseudocomponents, showing a good performance (Carreón-Calderón et al, 2012;Xu et al, 2015). Carreón-Calderón et al (2012) presented a new characterization procedure based on group contribution methods. They used selected functional groups to assign a hypothetical chemical structure to an undefined petroleum fraction by a minimization process of its corresponding Gibbs free energy.…”

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Abstract -Hydrogen solubility in heavy undefined petroleum fractions is estimated by taking as starting point a method of characterization based on functional groups [Carreón-Calderón et al (2012) Ind. Eng.

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“…This procedure was tested with seven undefined petroleum fractions from 27 to 6 API over wide ranges of pressure and temperature (323.15 to 623.15 K). The results seem to be in good agreement with experimental data (overall Relative Average Deviation, RAD < 15%).Résumé -Solubilité de l'hydrogène dans des fractions indéfinies du pétrole lourd à l'aide de la méthode de contribution de groupes -La solubilité de l'hydrogène dans des fractions indéfinies du pétrole lourd est estimée en prenant comme point de départ la méthode de contribution de groupes [Carreón-Calderón et al (2012) Ind. Eng.…”

“…Résumé -Solubilité de l'hydrogène dans des fractions indéfinies du pétrole lourd à l'aide de la méthode de contribution de groupes -La solubilité de l'hydrogène dans des fractions indéfinies du pétrole lourd est estimée en prenant comme point de départ la méthode de contribution de groupes [Carreón-Calderón et al (2012) Ind. Eng.…”