Studies on Large Crude Oil Alkanes. Ii. Isolation and Characterization of Aromatic Waxes and Waxy Asphaltenes.

Carbognani, Lante; DeLima, Lola; Orea, Miguel; Ehrmann, Ursula

doi:10.1080/10916460008949863

Cited by 49 publications

(25 citation statements)

References 17 publications

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“…The reason is that most of the asphaltenes will not precipitate from the other components at the testing temperature (about 5°C), however, the microcrystalline waxes (>C 40 ), which coprecipitate with asphaltenes and contribute to asphaltenes during the deasphaltening process (Thanh et al , 1999), may crystallize at the testing temperature. Moreover, in asphaltenes, these waxy molecules may also crystallize during cooling and result in highly insoluble organic composites in bitumen (Carbognani et al , 2000; Lu et al , 2005). As a result, a phase‐separated microstructure is formed, which contributes to the formation of ‘bee‐like’ structures.…”

Section: Resultsmentioning

confidence: 99%

Effect of aging on morphology of organo-montmorillonite modified bitumen by atomic force microscopy

Zhang

Wang

2010

Journal of Microscopy

127

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SummaryThe morphology of unmodified and organo-montmorillonite modified bitumens was investigated by atomic force microscopy. The influence of thin film oven test and ultraviolet aging on the morphology of the binders was also analysed. The atomic force microscopy results showed that bitumen displayed a 'bee-like' structure and the dimension of the 'bee-like' structures was decreased to some extent with the introduction of organo-montmorillonite. Organo-montmorillonite showed a better interaction with the dispersed domains in comparison with the matrix in bitumen, which led to an obvious increase in the contrast between the dispersed domains and the matrix in bitumen. Compared with the unmodified bitumen, the single-phase trend in the organo-montmorillonite modified bitumen could be effectively prevented during thin film oven test and ultraviolet aging, indicating its good aging resistance which was in accordance with changes in physical properties of the organo-montmorillonite modified bitumen before and after aging.

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Section: Resultsmentioning

confidence: 99%

Effect of aging on morphology of organo-montmorillonite modified bitumen by atomic force microscopy

Zhang

Wang

2010

Journal of Microscopy

127

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“…Liquid chromatography equipment was used Density at 25 C (Pycnometry) (Carbognani, 2001); 2 C 13 NMR aromaticity (Carbognani et al, 2000b). Liquid chromatography equipment was used Density at 25 C (Pycnometry) (Carbognani, 2001); 2 C 13 NMR aromaticity (Carbognani et al, 2000b).…”

Section: Dissolution Kinetics For Asphaltenes and Asphaltene-wax Compmentioning

confidence: 99%

“…Within fundamental aspects concerning solid deposition during crude oil production, the interaction of asphaltene-waxes has recently received closed attention in our laboratories (Carbognani and Orea, 1999;Carbognani et al, 2000b;Garcia, 2000;Garcia and Carbognani, 2001). Dissolution kinetics for pure asphaltene and complexes formed by these materials with diverse waxes were determined in order to shed light on the interaction among these hydrocarbon fractions (Garcia and Carbognani, 2001).…”

Section: Dissolution Kinetics For Asphaltene-wax Complexesmentioning

confidence: 99%

Solid Petroleum Asphaltenes Seem Surrounded by Alkyl Layers

Carbognani

Rogel

2003

Petroleum Science and Technology

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In this review, a comprehensive analysis of recent results obtained in our laboratory and published in the literature is presented, which points toward the existence of alkyl layers surrounding precipitated asphaltene solids. A micellar model for asphaltenes has been proposed, which explains many of the experimental determinations carried out to date with these compounds. The model considers the existence of alkyl moieties surrounding the inner aromatic cores. Faster dissolution kinetics of asphaltenes modified by coprecipitated waxes has been explained by the enhanced incorporation of alkanesurrounded particles into the eluent employed in the dissolution experiments. Finally, asphaltene volumetric changes brought by organic solvents have recently been studied, and can be explained by the existence of an alkyl layer prone to the incorporation of solvent molecules. This paper will discuss these aspects that seem to support the model long time ago postulated by Yen and coworkers.

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“…Carbognani et al also found that asphaltenes affect the precipitation of paraffins. In their work they took asphaltic cuts from two Venezuelan crude oils, one paraffinic and one naphthenoaromatic, also tested a 28.9°API Venezuelan crude oil that had been stored for 4 years at ambient conditions (25 °C, 0.9 atm), and slowly precipitated a solid sediment.…”

Section: Introductionmentioning

confidence: 96%

Understanding the Effect of Chemical Structure of Asphaltenes on Wax Crystallization of Crude Oils from Colorado Oil Field

2017

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the structural differences of asphaltenes in Colombian light crude oils from the same field, i.e., the Colorado oilfield, were presented. Colorado crude oil is a light crude with very low content of asphaltenes (<0.3%, w/w) and presents paraffin crystallization problems during its production. In the parafinic deposits, asphaltenes have also been found. In this work, a new methodology is proposed to determine the effects of chemical structure and concentration of asphaltenes on the wax crystallization of the crude oils from the Colorado oilfield. Six crude oils (from different sands) were fractionated in their respective asphaltenes and maltenes. The crystallization properties of crude oils and maltenes were obtained: wax appearance temperature (WAT), pour point, and crystallization enthalpy. Asphaltenes were characterized by nuclear magnetic resonance analysis, mass spectrometry, X-ray diffraction, and Raman spectroscopy, and their main average molecular parameters (AMPs) were calculated. Partial least-squares regression (PLS) analysis was used to understand the influence of asphaltenes chemical structure on the crystallization processes. The proposed characterization−statistical analysis methodology allowed for the understanding of the effect of the average molecular structure of asphaltenes on the crystallization properties of paraffins from the crude oils of the Colorado field. The effect of asphaltenes was analyzed through correlation between the differences in WAT, the differences in pour poin,t and the relative crystallization (C r ) with the AMPs of asphaltenes. The AMPs of the asphaltenes causing the greatest impact on the increase of the crystallization temperature are the pericondensed carbons (C aaa ), ratio of peripheral carbons/aromatic carbons (C p /C ar ), and aromaticity factor ( f a ), and decreases in these properties are attributed to the length of the aliphatic chains (n) and the naphthenic rings (C n ); the concentration of asphaltenes (C oasf ) has little effect. The degree of crystallization is increased by f a and decreased with C aaa , C p /C ar , paraffinic carbons (C s ), and C oasf . The pour point is only increased by f a and decreased withC aaa and C n , and C oasf is negligible.

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Studies on Large Crude Oil Alkanes. Ii. Isolation and Characterization of Aromatic Waxes and Waxy Asphaltenes.

Cited by 49 publications

References 17 publications

Effect of aging on morphology of organo-montmorillonite modified bitumen by atomic force microscopy

Effect of aging on morphology of organo-montmorillonite modified bitumen by atomic force microscopy

Solid Petroleum Asphaltenes Seem Surrounded by Alkyl Layers

Understanding the Effect of Chemical Structure of Asphaltenes on Wax Crystallization of Crude Oils from Colorado Oil Field

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