Reversibility and Inhibition of Asphaltene Precipitation in Brazilian Crude Oils

Mohamed, Rahoma S.; Loh, Watson; Ramos, A. C. S.; Delgado, Claudio C.; Almeida, Valdeci R.

doi:10.1080/10916469908949754

Cited by 42 publications

(35 citation statements)

References 10 publications

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“…As n -heptane was added, we would expect the solubility of the less polar asphaltene molecules when the system achieved the range of solubility parameters in which these molecules are soluble, followed by the precipitation from the liquid phase of the more polar asphaltene molecules when the system achieved the precipitation solubility parameter of these molecules. Although the asphaltene precipitation phenomenon is reversible, many authors have reported the presence of hysteresis, which disfavors the resolubilization of the asphaltenic particles . This can explain the fact that the solubilization did not occur at the beginning of n -heptane addition.…”

Section: Resultsmentioning

confidence: 99%

Flocculation of Asphaltenes by Polymers: Influence of Polymer Solubility Conditions

et al. 2018

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Sulfonated polystyrene has shown flexible action as an asphaltene dispersant/flocculant as a function of the degree of sulfonation and concentration used. In this work, samples of sulfonated polystyrene with different sulfonation degrees were assessed in precipitation assays in model asphaltene systems, with variation of the asphaltene fractions (asphaltenes extracted by n-pentane and n-heptane, C5I and C7I, respectively), asphaltene concentration, polymer concentration, and medium used to dissolve the polymer and asphaltenes. The precipitation tests were carried out with an ultraviolet–visible spectrometer, and the absorbance values were converted into asphaltene concentration values in solution by using calibration curves. The results showed that the concentration of sulfonic groups at which the polymer performs best as an asphaltene flocculant is 10 mol %. The dependence of the polymer’s effect as a flocculant or stabilizer of asphaltenes in function of its hydrophilicity and concentration was confirmed. Moreover, the results indicate there is a strong relationship between the polymer’s solubility in the medium and its flocculant action, which is significantly more effective when the polymer does not have strong affinity for the medium.

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Section: Resultsmentioning

confidence: 99%

Flocculation of Asphaltenes by Polymers: Influence of Polymer Solubility Conditions

et al. 2018

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“…The effect of additives on the inhibition of asphaltene precipitation has been investigated [10]. The result showed that ethoxylated nonylphenol and hexadecyl trimethyl ammonium bromide exhibit a positive performance.…”

Section: Introductionmentioning

confidence: 94%

Effects of Short-Chain n-Alcohols on the Properties of Asphaltenes at Toluene/Air and Toluene/Water Interfaces

Martins

Santos

2018

Colloids and Interfaces

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Abstract:Crude oil asphaltenes contain a wide series of chemical species, which includes the most polar compounds and interfacially active agents from the petroleum. Asphaltenes have been considered to be implicated in foam and emulsion formation during the petroleum recovery and production process. In this work, the interfacial activity of organic solutions containing asphaltene and n-alcohols was investigated. Asphaltene extraction from a 28 • API crude oil produced 2.5 wt % of n-pentane precipitated asphaltene (C5I). Dynamic surface and interfacial tensions of asphaltene solutions were assessed by the pendant drop method. Asphaltene films were evaluated at the air-water interface using a Langmuir trough. Results were expressed by means of the interfacial tension time-dependence. Interfacial tension measurements showed alcohols reduce the toluene/water interfacial tension of asphaltene solutions. The interfacial tension was reduced from 23 mN/m to 15.5 mN/m for a 2 g/L solution of asphaltene plus n-butanol. Higher asphaltene concentrations did not affect the toluene/air surface tension. The effects of n-alcohols on the asphaltene surface activity was dependent on the asphaltene aggregation state. n-Alcohols modify the asphaltene film elasticity and the film phase behavior.

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“…Apparent irreversibilities have also been associated with inappropriate reversibility criteria [79] and to the existence of an energy barrier to asphaltene dissociation [80]. In spite of the difficulties, the number of studies supporting reversibility is remarkable [74,75,[79][80][81][82][83].…”

Section: Introductionmentioning

confidence: 97%

Thermodynamic modelling of asphaltene precipitation and related phenomena

Forte

Taylor

2015

Advances in Colloid and Interface Science

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Reversibility and Inhibition of Asphaltene Precipitation in Brazilian Crude Oils

Cited by 42 publications

References 10 publications

Flocculation of Asphaltenes by Polymers: Influence of Polymer Solubility Conditions

Flocculation of Asphaltenes by Polymers: Influence of Polymer Solubility Conditions

Effects of Short-Chain n-Alcohols on the Properties of Asphaltenes at Toluene/Air and Toluene/Water Interfaces

Thermodynamic modelling of asphaltene precipitation and related phenomena

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