Aggregation of Asphaltenes Obtained From a Brazilian Crude Oil in Aromatic Solvents

Loh, Watson; Mohamed, Rahoma S.; Ramos, A. C. S.

doi:10.1080/10916469908949712

Cited by 34 publications

(32 citation statements)

References 12 publications

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“…Some authors have observed a critical micelle concentration (cmc) for asphaltene solutions in solvents like toluene or pyridine (4,16). The cmc value depends on the alkane, the asphaltene origin, and the solvent used (17,18). However Yarranton et al did not observe any cmc (19).…”

Section: Introductionmentioning

confidence: 94%

Dynamic Surface Properties of Asphaltenes and Resins at the Oil–Air Interface

Bauget

Langévin

Lenormand

2001

Journal of Colloid and Interface Science

149

110

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Section: Introductionmentioning

confidence: 94%

Dynamic Surface Properties of Asphaltenes and Resins at the Oil–Air Interface

Bauget

Langévin

Lenormand

2001

Journal of Colloid and Interface Science

149

110

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“…Many papers explain the high viscosity of heavy crude oils with the presence of this solid precipitate. Nevertheless, most of these studies were realized with simple organic solvents [1][2][3][4][5][6][7][8][9][10] and just a few with heavy crude oils [11] or similar systems as bitumen [12][13][14][15][16][17], vacuum residues [18][19][20] or coal derived liquids [21]. More experimental work on real systems is necessary.…”

Section: Properties Of Heavy Crude Oils: 2 Domains Of Asphaltenes Conmentioning

confidence: 99%

Rheological and Structural Properties of Heavy Crude Oils in Relation with their Asphaltenes Content

Hénaut

Barré

Argillier

et al. 2001

SPE International Symposium on Oilfield Chemistry

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractHeavy oils represent a strategic source of hydrocarbons as their reserves are of the same order of magnitude as the ones of conventional oils. The production of these crudes remains low, in particular because of their very high viscosities. The asphaltenes which they contain are known to be responsible for this situation. Actually, many studies have shown that these high molecular weight polar components self-associate more or less severely depending on different parameters like temperature, concentration and solvent quality. The experimental work was usually performed using simple organic solvents (toluene, heptane…) which are not representative of complex heavy crude oils. Therefore, we decided to investigate the rheological behavior of asphaltenes in their natural environment and in relation with their structure. Samples coming from the same crude oil were prepared with different asphaltenes contents, from 0 to 20% in weight. The apparent viscosity and the oscillatory modulus (G' and G") were measured with a controlled stress rheometer and SAXS were undertaken. Two domains were identified. The first one concerns the dilute samples for which the relative viscosity increases linearly with the weight fraction of asphaltenes. In this domain, the aggregates of asphaltenes stay independent from one another and have the same radius of gyration. For the more concentrated samples, the viscosity increases dramatically because of the aggregates entanglement as was observed by SAXS. Concerning the oscillatory experiments, the elastic character increases from the first domain to the second one, which confirms that a structural change occurs. Combining the rheological measurements and SAXS reveals an analogy between heavy crude oils and concentrated colloidal systems of polymer solutions. All these results help the understanding of the flow properties of heavy crude oils and aim to contribute to the improvement of their transport.

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“…The solvated asphaltene crystallites are the primary particles of the colloidal dispersed phase. These particles can associate and aggregate, forming various size particles depending on temperature, pressure and concentration [8,15,16,19,21,[26][27][28][29][30][31][32][33][34][35]42,43]. In fact, asphaltenes are natural surfactants stabilising water/crude oil emulsion [21,22,[44][45][46][47][48][49][50][51][52].…”

Section: Introductionmentioning

confidence: 99%

Adsorption of asphaltenes from toluene on mineral surface

Marczewski

Szymula

2002

Colloids and Surfaces A: Physicochemical and Engineering Aspect

173

124

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Undesirable adsorption of asphaltenes on rock minerals was studied. Asphaltenes are an important component of crude oil, being also natural surfactant stabilising water/crude oil emulsions. Owing to their chemical nature, asphaltenes are able to associate, form micelles and create a surface charge at the interface. Asphaltenes may be adsorbed on rock reservoir from the organic solvents in crude oil and as an organic colloid, they can adsorb electrolyte ions from aqueous solution. In order to simulate natural conditions we used asphaltenes from local drills, toluene as solvent and several typical oxides and carbonate rock components or minerals as adsorbents. Our study included natural Brazilian quartz, dolomite, calcite and kaolin, as well as pure oxides: Fe 2 O 3 and TiO 2 . The typical shape of asphaltene adsorption isotherms was obtained for all systems studied with the characteristic 'steps' which indicate changes in the state of asphaltene molecules in the solution and at the mineral surface. Those changes are related to the asphaltene association and further formation of hemimicelles and micelles.

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Aggregation of Asphaltenes Obtained From a Brazilian Crude Oil in Aromatic Solvents

Cited by 34 publications

References 12 publications

Dynamic Surface Properties of Asphaltenes and Resins at the Oil–Air Interface

Dynamic Surface Properties of Asphaltenes and Resins at the Oil–Air Interface

Rheological and Structural Properties of Heavy Crude Oils in Relation with their Asphaltenes Content

Adsorption of asphaltenes from toluene on mineral surface

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