Hysteresis in Asphaltene Precipitation and Redissolution

Beck, James S.; Svrcek, William Y.; Yarranton, Harvey W.

doi:10.1021/ef049707n

Cited by 31 publications

(41 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In contrast, if the flocculation conditions remain close to the flocculation point, flocculation should be considered as reversible. In a recent study, Beck et al (2005) demonstrated hysteresis between asphaltene precipitation and redissolution. This effect is increased in the presence of air due to oxidation reactions.…”

Section: Flocculation Reversibility?mentioning

confidence: 98%

Characterisation of Asphaltenes and Modelling of Flocculation – State of the Art

Pina¹,

Mougin²,

Béhar³

2006

Oil & Gas Science and Technology - Rev. IFP

View full text Add to dashboard Cite

Résumé -Caractérisation des asphaltènes et modélisation de la floculation -État de l'Art -Ce travail présente un état de l'art concernant la floculation des asphaltènes avec deux grands items : la caractérisation des asphaltènes dans différents milieux et la modélisation de la floculation. Cette revue commence par une caractérisation des asphaltènes proprement dite puis des caractérisations de ces derniers dans des solvants synthétiques ou des bruts. Nous insistons sur les techniques de détermination de masses molaires et de diffraction. L'incidence d'un ajout de bon/mauvais solvant est également discutée. La seconde partie de cette revue concerne la modélisation de la floculation. Elle examine les différents modèles de la littérature avant de présenter celui de Szewczyk et Béhar (1999) et son intégration dans un simulateur de réservoir. Les modèles disponibles requièrent encore des données expérimentales délicates à acquérir et un effort de recherche doit être réalisé pour améliorer cet état de fait. Abstract -Characterisation of Asphaltenes and Modelling of Flocculation -State of the Art -This document describes a state of the art concerning the flocculation of asphaltenes with two major sections: characterisation of asphaltenes in various environments and modelling of flocculation. This review starts with the characterisation of asphaltenes as such, then their characterisation in synthetic solvents or crudes. Emphasis is placed on molar mass determination and diffraction techniques. The impact of adding a good/poor solvent is also discussed. The second part of this review is dedicated to modelling.We first examine the various models in the literature before describing the Szewczyk and Béhar (1999) model and its integration in a reservoir simulator. The models available still require experimental data which is difficult to collect and further research is needed to improve this situation.Petroleum Industry Applications of Thermodynamics Applications de la thermodynamique dans l'industrie pétrolière

show abstract

Section: Flocculation Reversibility?mentioning

confidence: 98%

Characterisation of Asphaltenes and Modelling of Flocculation – State of the Art

Pina¹,

Mougin²,

Béhar³

2006

Oil & Gas Science and Technology - Rev. IFP

View full text Add to dashboard Cite

show abstract

“…The kinetics of asphaltene precipitation was measured for a variety of bitumens and crude oils in an air atmosphere and compared with the data collected in nitrogen previously reported by Duran et al 1 In nitrogen, the onsets and yields became invariant after 50 to 150 h, consistent with reaching an equilibrium condition. In air, the onsets and precipitation yields followed the same trend over time as in nitrogen for approximately 50 h but then deviated; in particular, the onsets decreased and the yields increased gradually over time for the 19 and k−1 and GM2 from Maqbool et al 2,29,57 The asphaltene contents are reported in Tables 1 and 5. duration of the experiments, consistent with the observations of Maqbool et al 2,29 The difference was attributed to oxygen, which likely alters the composition and reduces the solubility of the asphaltenes.…”

Section: Discussionmentioning

confidence: 87%

“…The mechanism was not investigated in this study but, as discussed previously, oxidation of the asphaltenes can occur even under ambient conditions and tends to reduce their solubility. 39 Figure 7 compares the yields from WC-B-B2 bitumen with yields from two other Western Canadian bitumens, all diluted with n-heptane under ambient conditions: (1) WC-B-A0, an Athabasca bitumen; 19 (2) WC-B-A3 (this study). Although the amount of precipitant required to obtain the same yield for each sample is different, the trends are the same for all three oils.…”

Section: Energy and Fuelsmentioning

confidence: 97%

See 1 more Smart Citation

Effect of Air on the Kinetics of Asphaltene Precipitation from Diluted Crude Oils

et al. 2019

Self Cite

View full text Add to dashboard Cite

The kinetics of asphaltene precipitation was investigated for five crude oils diluted with n-heptane at 21 °C in air and nitrogen atmospheres. The onset of precipitation, defined as the precipitant (n-heptane) content at which detectable asphaltene particles first appear, was measured in air at different contact times using optical microscopy and a gravimetric method. Asphaltene yields (mass asphaltene/mass oil) were measured in air over time gravimetrically. The data were compared with yields and "yield onsets" previously measured for the same mixtures in a nitrogen atmosphere. 1 In a nitrogen atmosphere, the yields increased and the onsets decreased over approximately 50 h but then reached plateau values, indicating that an equilibrium condition existed. In an air atmosphere, the yields and onsets were the same as in nitrogen for the first 50 h, but then the yields gradually increased for the duration of the experiments. The onsets shifted to lower values over time, and there was no equilibrium onset condition. Hence, precipitation data collected in air below 50 h can be used for kinetic modeling as is; however, data collected in air over longer times overstates asphaltene yields under anaerobic conditions and requires correction. It is hypothesized that the oxygen in the air catalyzes or participates in reactions that alter the asphaltenes and other crude oil components over time so that they become less soluble. The oxidation rate appears to correlate approximately with the asphaltene content of the oil. The population balance first developed by Maqbool et al., Modeling the Aggregation of Asphaltene Nanoaggregates in Crude Oil-Precipitant Systems. Energy Fuels, 25 (4), 2011, 1585-1596, and later modified by Duran et al., Kinetics of Asphaltene Precipitation/Aggregation from Diluted Crude Oil. Fuel, 255, 2019, 115859, was further adapted to account for the increase in yield over time due to oxygen by introducing a term for the generation of unstable asphaltene primary particles. The proposed model matched the precipitation yield data from this study and from the literature with an average absolute deviation of less than 2 wt %.

show abstract

“…Some authors have regarded asphaltene precipitation only as partially reversible [76], especially when asphaltenes are destabilised well beyond the onset conditions [77,78]. 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: 99%