Fullerenic structures derived from oil asphaltenes

Camacho-Bragado, G.A.; Santiago, Patrícia; Marín-Almazo, M.; Espinosa, M.; Romero, E.T; Murgich, Juan; Rodríguez-Lugo, Ventura; Lozada‐Cassou, Marcelo; José–Yacamán, Miguel

doi:10.1016/s0008-6223(02)00199-9

Cited by 43 publications

(33 citation statements)

References 17 publications

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“…The porous structure of precipitates may be the result of the archipelago‐type molecular structure of asphaltene, as concluded by Spiecker et al . Different HRTEM images revealed that asphaltene is organized by nanometric aggregates …”

Section: The Size and Structure Of Asphaltene Aggregatesmentioning

confidence: 74%

“…The SEM, tunneling electron microscopy, HRTEM analysis methods are used to characterize the asphaltene aggregates on surfaces. The effects of different parameters such as oil solvent type and temperature on the precipitated asphaltenes from oil have been studied using these techniques by different researchers . In the SEM studies, two different morphologies including compact structure and porous structure have been observed .…”

Section: The Size and Structure Of Asphaltene Aggregatesmentioning

confidence: 99%

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A comprehensive study on mechanism of formation and techniques to diagnose asphaltene structure; molecular and aggregates: a review

Hosseini-Dastgerdi

Tabatabaei-Nejad

Khodapanah

et al. 2014

Asia-Pacific J Chem Eng

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As the formation of asphaltene aggregates causes its deposition in various processes, exact determination of the molecular and aggregate structure and mechanism of aggregate formation is very important in order to prevent asphaltene deposit formation. The aim of this paper is to review the molecular and aggregate structure of asphaltene using various techniques. The other purpose is to specify and compare different mechanisms of aggregate formation, suggested by researchers. These mechanisms are proposed by researchers according to the molecular characteristics of asphaltene and the structure of aggregates. Researchers have considered four general models for the formation mechanism of asphaltene aggregates: the micellar/colloidal, polymeric, solubility, and modified Yen models. In comparison with other models, the modified Yen model shows more consistency with new studies, which determine the island molecular structure and small nano-aggregates for asphaltene. Experimental studies show that the dominant mechanism of aggregate formation depends on asphaltene architecture, intermolecular forces, and the solubility definition of asphaltene. Depending on the asphaltene source, solvent, thermodynamic conditions, and various techniques such as near-infrared spectroscopy, nuclear magnetic resonance, small-angle neutron scattering, and small-angle X-ray scattering, different structural information on the shape (spheres, discoid, oblate, membrane-like, prolate cylinders, and mass fractal aggregates) and size of aggregates has been reported.

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Section: The Size and Structure Of Asphaltene Aggregatesmentioning

confidence: 74%

Section: The Size and Structure Of Asphaltene Aggregatesmentioning

confidence: 99%

A comprehensive study on mechanism of formation and techniques to diagnose asphaltene structure; molecular and aggregates: a review

Hosseini-Dastgerdi

Tabatabaei-Nejad

Khodapanah

et al. 2014

Asia-Pacific J Chem Eng

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“…Scanning electron microscopy does not give us complete information about the processes of aggregation of asphaltenes [8,15,16], and therefore in the paper studied by transmission electron microscopy. Results of the TEM analyses of the asphaltene surface precipitated from natural bitumen were shown at Fig.…”

Section: Resultsmentioning

confidence: 99%

Changing the Structure of Resin-Asphaltenes Molecules in Cracking

Imanbayev

Ongarbayev

Mansurov

et al. 2017

Eurasian Chem. Tech. J.

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In the paper, structural changing of resin-asphaltene molecules in cracking process of oil sand bitumen are investigated. Cracking process to natural bitumen carried out in an open-to-air reactor, which extracted from oil sand by organic solvent. Reaction temperature was 450 °С and process duration was 60 min. The reactor was heated at a rate of 10 °C/min up to the desired temperature. Di-tert-butyl peroxide was used as radical formation additive. When limiting oxygen, it can be used catalyst molecule supplies as the oxidizer. The thermal destruction processes of heavy hydrocarbons with the catalyst make it possible to increase the yield of low boiling liquid products with the formation of coke and gas as by-products. High temperature leads to increase the oil content, and decrease the total resinasphaltene components in bitumen. Monte Carlo method used for construction the molecular structure of resin-asphaltene components. The calculations data determined the most stable conformation of resins and asphaltenes molecules, that the stability of the molecules affect structural characteristics such as the number of structural blocks, their size and spatial arrangement of atoms with respect to each other. Microscopic images showed that the asphaltenes have around 40‒50 nm of particle size, which large monolithic switching, weakly focused on a major surface, provided with amorphous carbon.

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“…Sparingly soluble asphaltenes are believed to be lost in oil migration processes. A high resolution microscopy study of asphaltene aggre gates [18] revealed the occurrence of dealkylated con densed structures, such as fullerene molecules, com posed mainly of carbon and hydrogen and containing sulfur and vanadium atoms. A nonuniform composi tion of asphaltenes and isolation of different fractions from them were also reported in [19].…”

Section: Resultsmentioning

confidence: 99%

Hydrothermal transformations of asphaltenes

2012

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A characteristic feature of heavy oils and natural bitumens is a high concentration of resin-asphaltene compounds [1][2][3][4]. Asphaltenes are very complex polycyclic entities whose carbon skeleton includes naphthenic, aromatic, and heteroaromatic cycles with aliphatic side chains. A high molecular mass and high aromaticity of asphaltenes determine their tendency toward the formation of molecular associates as colloi dal particles with a considerable size in petroleum dis perse systems; as a result, their chemical and physical behavior create problems in the production and pro cessing of heavy hydrocarbon stock [5][6][7][8].At present, thermal steam and gas-steam treat ments are widely used for enhanced oil recovery from productive formations with highly viscous oil and bitu minous rocks impregnated with heavy, viscous bitu men [9][10][11]. However, more detailed information on the composition of heavy hydrocarbon feedstock, the character of its transformation during various thermal treatments, and the quality of the products is necessary for their successful application. Thus, studying changes in the structure and properties of asphaltenes induced by hydrothermal factors is currently an important task aimed at searching for optimum tech nologies of enhanced development of fields of heavy, highly viscous oils and natural bitumens and adjusting conventional technologies to the geologicalgeochemical conditions of pool formation in particu lar fields.The objective of this work was to obtain new data on changes in the structure and properties of asphalt enes, isolated from crude oils and natural bitumens of various component compositions and chemical types in hydrothermal processes, under conditions that sim ulate the effect of thermal steam treatment on a pro ducing formation. EXPERIMENTALThe objects of study were asphaltenes precipitated from crude oils and natural bitumens of various chem ical types according to the standard procedure in a 40 fold excess of petroleum ether with the boiling tem perature of 40-70°С [12]:⎯type B 1 bitumens isolated from outcropping Per mian bituminous sandstones of the Shugurovskoe and Spiridonovskoe fields by extraction in a Soxhlet appa ratus with a mixture of the organic solvents chloro form-benzene-isopropyl alcohol taken in a 1 : 1 : 1 ratio;⎯type A 2 heavy oil produced by borehole mining from Permian deposits at a depth of 75-97.6 m of the Ashal'chinskoe field (well 82); and ⎯type A 1 light paraffinic oil produced from Middle Devonian Givetian deposits at a depth of 1880 m in the Bavly field (well 475);The experiments were run in a vertical flow reactor at 360°С by 5 h treatment of asphaltenes (in an amount of 2-3 g) in the contact zone of the reactor with a steam-gas mixture produced using continuous supply of water and hydrogen onto disc evaporators at the top of the reactor. The flow rate of hydrogen was ≈2% of the steam flow rate. The steam-gas mixture with liquid products of hydrothermal conversion of asphaltenes effluent from the reactor was condensed in a condenser and ...

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Fullerenic structures derived from oil asphaltenes

Cited by 43 publications

References 17 publications

A comprehensive study on mechanism of formation and techniques to diagnose asphaltene structure; molecular and aggregates: a review

A comprehensive study on mechanism of formation and techniques to diagnose asphaltene structure; molecular and aggregates: a review

Changing the Structure of Resin-Asphaltenes Molecules in Cracking

Hydrothermal transformations of asphaltenes

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