Colloidal Properties of Asphaltenes in Organic Solvents

Sheu, Eric Y.; Storm, David A.

doi:10.1007/978-1-4757-9293-5_1

Cited by 48 publications

(52 citation statements)

References 41 publications

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“…It is based on size exclusion from pores of different diameters and consequently has problems when molecular Yields of SARA fractions. aggregation occurs; this could be an issue for asphaltene molecules which are believed to undergo a form of micellization, even at very low concentrations (Sheu and Storm, 1995). However, there is no indication in the literature that nonasphaltene components (maltenes) form aggregates.…”

Section: Molecular Weight and Elemental Analysismentioning

confidence: 99%

Canadian Crudes: A Comparative Study of SARA Fractions from a Modified HPLC Separation Technique

Woods

Kung

Kingston

et al. 2008

Oil & Gas Science and Technology - Rev. IFP

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Résumé -Pétroles bruts canadiens : étude comparative des fractions SARA à partir d'une technique de séparation HPLC modifiée -Ces dernières années, une réduction mondiale des réserves de pétrole conventionnel pouvant être exploitées a amené à une augmentation des activités d'exploration et de production des pétroles bruts les plus lourds. Au Canada, il a été demandé aux unités de valorisation d'étudier les pétroles lourds et les bitumes provenant des sables bitumineux, plus accessibles mais plus difficiles à exploiter. Afin d'améliorer les conditions de fonctionnement des installations et d'évaluer leur impact sur l'environnement, une connaissance approfondie de la structure moléculaire et du comportement du pétrole source est nécessaire. Les problèmes liés aux hydrotraitements des fractions riches en azote sont particulièrement préoccupants. L'approche utilisée ici implique la séparation d'une série de divers pétroles bruts canadiens (bitumes provenant des sables bitumineux et pétroles lourds et conventionnels) ayant des teneurs en asphaltènes et maltènes variables, suivie d'un fractionnement supplémentaire des maltènes au moyen de la Chromatographie en Phase Liquide à Haute Performance (HPLC). Cette approche diffère de la séparation conventionnelle SARA (saturés, aromatiques, résines et asphaltènes) car les multiples fractions sont facilement séparées sur la base des différences de polarité et fournissent de ce fait des informations plus détaillées sur la répartition des classes de composants. Les fractions séparées peuvent être caractérisées au moyen de différentes méthodes analytiques, y compris : chromatographie par perméation de gel (GPC) pour déterminer le poids moléculaire moyen, le calcul de paramètres moléculaires en utilisant les analyses CHNS en association avec la spectroscopie 1 H et 13 C NMR et l'analyse XPS de groupes chimiques au moyen de la déconvolution de pic. Les bitumes contiennent moins de saturés mais plus de résines et d'asphaltènes que tous les autres pétroles lourds testés. A l'inverse, le pétrole conventionnel est associé à un contenu en saturés plus élevé et à la quantité de résines et d'asphaltènes la moins importante. Les rendements en fractions aromatiques provenant de différentes sources sont tous situés dans une gamme relativement étroite. Il est remarquable que les fractions SARA de chaque pétrole aient des propriétés moyennes en masse relativement voisines. Toutes les fractions résines contenaient plus de 40 % de l'azote total, c'est-à-dire plus que les quantités contenues dans les fractions correspondantes d'asphaltène. On a observé, pour les sous-fractions de résines, des différences relativement moins importantes entre les poids moléculaires, les ratios H/C atomiques et l'aromaticité (C ar ). La différence substantielle dans le comportement de l'élution HPLC pour ces sousfractions semble pouvoir être attribuée à la distribution asymétrique des composants azotés polaires pour

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Section: Molecular Weight and Elemental Analysismentioning

confidence: 99%

Canadian Crudes: A Comparative Study of SARA Fractions from a Modified HPLC Separation Technique

Woods

Kung

Kingston

et al. 2008

Oil & Gas Science and Technology - Rev. IFP

View full text Add to dashboard Cite

show abstract

“…Several studies have been carried out employing various methods to determine the ''critical micelle concentration'' (CMC) of asphaltenes, i.e., the concentration below which asphaltenes remain as monomer species (Taylor 1992). The experimental methods used, including calorimetry (Andersen and Bridi 1991;Andersen and Christensen 2000), surface tension (Sheu 1996;Carbognani et al 1997;Mohamed et al 1999;Rogel et al 2000), viscosity (Storm et al 1991), vapor pressure osmometry (Yarranton et al 2000), NIR spectroscopy (Mullins 1990;Kyeongseok et al 2004), and small-angle scattering measurements (Sheu and Storm 1995) show a variety of the CMC values and indicate that this parameter depends on the asphaltene origin and the solvent used. For instance, Andersen and Bridi (1991) have used microcalorimetric titration for measuring the CMCs of Venezuelan asphaltenes in different organic solvents.…”

Section: Introductionmentioning

confidence: 99%

Investigation of structural parameters and self-aggregation of Algerian asphaltenes in organic solvents

2015

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Elemental analysis, Fourier transform infrared (FTIR), 1 H-NMR, fluorescence spectroscopy, and surface tension methods have been used to characterize the molecular structure and the aggregation behaviors of two asphaltenic fractions derived, respectively, from an Algerian petroleum well and a corresponding storage tank deposit. Elemental analysis, FTIR, 1 H-NMR, and fluorescence spectroscopy were used to investigate the chemical composition and structural parameters of asphaltenes, while the surface tension method was used to measure the critical micelle concentration (CMC) in organic solvents with different solubility parameters and polarities in order to characterize the asphaltenes' aggregation behaviors. Results show that the unstable asphaltenes fraction extracted from the storage tank deposit possesses a higher polarity (higher heteroatoms content) and a lower aromaticity than stable asphaltenes from the petroleum well. The CMC results indicate that asphaltenes with high polarity and low aromaticity have a high solubility in polar solvents such as nitrobenzene, whereas asphaltenes with low polarity and high aromaticity are more soluble in solvents with weak polarity, like toluene. It is concluded that the difference of structure of asphaltene samples and polarity of solvents can lead to difference of aggregation behaviors.

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“…We recall here that according to the current accepted colloidal model for bitumen, asphaltene molecules rich in resins as peptizing agents self-assembly into micellar-like structures dispersed into the continuous phase composed mainly by the saturated and aromatic oil fractions (maltene) [25][26][27]. The SARA content of the pristine bitumen was determined (see Section 2) and the results are shown in Table 1.…”

Section: Resultsmentioning

confidence: 99%

Mechanical Resilience of Modified Bitumen at Different Cooling Rates: A Rheological and Atomic Force Microscopy Investigation

et al. 2017

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Due to the wide variation in geographic and climatic conditions, the search for high-performance bituminous materials is becoming more and more urgent to increase the useful life of pavements and reduce the enormous cost of road maintenance. Extensive research has been done by testing various bitumen modifiers, although most of them are petroleum-derived additives, such as polymers, rubbers and plastic, which in turn do not prevent oxidative aging of the binder. Thus, as an alternative to the most common polymeric rheological modifiers, selected binder additives falling in the categories of organosilane (P2KA), polyphosphoric acid (PPA) and food grade phospholipids (LCS) were homogeneously mixed to a base bitumen. The goal was to analyse the micro-morphology of the bitumens (neat and modified) subjected to different cooling rates and to find the corresponding correlations in the mechanical response domain. Therefore, microstructural investigations carried out by Atomic Force Microscopy (AFM) and fundamental rheological tests based on oscillatory dynamic rheology, were used to evaluate the effect of additives on the bitumen structure and compared with pristine binder as a reference. The tested bitumen additives have been shown to elicit different mechanical behaviours by varying the cooling rate. By comparing rheological data, analysed in the framework of the "weak gel" model, and AFM images, it was found that both P2KA and PPA altered the material structure in a different manner whereas LCS revealed superior performances, acting as "mechanical buffer" in the whole explored range of cooling rates.

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Colloidal Properties of Asphaltenes in Organic Solvents

Cited by 48 publications

References 41 publications

Canadian Crudes: A Comparative Study of SARA Fractions from a Modified HPLC Separation Technique

Canadian Crudes: A Comparative Study of SARA Fractions from a Modified HPLC Separation Technique

Investigation of structural parameters and self-aggregation of Algerian asphaltenes in organic solvents

Mechanical Resilience of Modified Bitumen at Different Cooling Rates: A Rheological and Atomic Force Microscopy Investigation

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