The effect of temperature on the molecular structure of Raman asphaltenes during pyrolysis

Akmaz, Solmaz; Gürkaynak, M. Ali; Yaşar, Muzaffer

doi:10.1016/j.jaap.2012.03.015

Cited by 24 publications

(19 citation statements)

References 18 publications

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“…The union of two alkyl radicals could produce alkanes and alkenes with longer chains. They remained reactive and continued to crack and made more products to generate larger alkyl structures, as verified by Alshareef [32]. On the contrary, homolytic dissociation occurred to generate lighter fractions.…”

Section: Hypothetical Structures and Transformation Of Asphaltenes Dumentioning

confidence: 82%

“…Gray et al [31] proposed that aromatic rings of asphaltenes do not crack at temperatures between 330-550 • C, so the polycyclic part of the layer unit is considered thermally stable and is conserved during pyrolysis. Additionally, the mechanism of free radical reaction abstracts hydrogens from the naphthenic and paraffinic fractions leading to generate more double bonds and aromatic rings in the core of the asphaltenes [32,33].…”

Section: Hypothetical Structures and Transformation Of Asphaltenes Dumentioning

confidence: 99%

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Mechanistic Approach to Thermal Production of New Materials from Asphaltenes of Castilla Crude Oil

2020

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Asphaltenes are compounds present in crude oils that influence their rheology, raising problems related to the extraction, transport, and refining. This work centered on the chemical and structural changes of the asphaltenes from the heavy Colombian Castilla crude oil during pyrolysis between 330 and 450 °C. Also, the development of new strategies to apply these macromolecules, and the possible use of the cracking products as a source of new materials were analyzed. The obtained products (coke, liquid, and gas) were collected and evaluated through the techniques of proton and carbon-13 nuclear magnetic resonance (1H and 13C NMR), elemental composition, Fourier-transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), saturates, aromatics, resins, and asphaltenes (SARA) analysis, and gas chromatography–mass spectrometry (GC-MS). A comparison of the applied methods showed that the asphaltene molecules increased the average size of their aromatic sheets, lost their aliphatic chains, condensed their aromatic groups, and increased their degree of unsaturation during pyrolysis. In the liquid products were identified alkylbenzenes, n-alkanes C9–C30, and n-alkenes. Moreover, the gaseous products included methane, ethane, propane, and pentane. An approach of the structural chain reaction was used to define the possible asphaltenes chemical structures before and after pyrolysis. In conclusion, this type of thermal process can be used as an easy route to attain new materials associated with specific structural units from the asphaltenes.

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Section: Hypothetical Structures and Transformation Of Asphaltenes Dumentioning

confidence: 82%

Section: Hypothetical Structures and Transformation Of Asphaltenes Dumentioning

confidence: 99%

Mechanistic Approach to Thermal Production of New Materials from Asphaltenes of Castilla Crude Oil

2020

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“…The thermal cracking commercially produces high-value liquids and pitch, because of practical application in processing vacuum asphaltene residues, as well as in refinery industry such as delayed coking, visbreaking and flexicoking, etc. The research of asphaltene pyrolysis reaction involves in temperature and reaction time in the inert atmosphere [174,[200][201][202] , and a series of kinetic models are developed [196,203] . The pyrolysis may undergo a multi-step process, so do asphaltenic core and maltene [171,201] .…”

Section: Hydroprocessing Pyrolysis and Gasificationmentioning

confidence: 99%

Asphaltenes: Separations, structural analysis and applications

Zuo

Shen

2019

Journal of Energy Chemistry

132

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“…It usually consists of highly condensed polyaromatic macromolecules bearing long aliphatic chains and alicyclic substituents (Mandal et al, 2012a, b). In the refining processes, asphaltene is prone to form coke and deactivate catalyst (Akmaz et al, 2012;Ayala et al, 2012;. Moreover, high concentrations of heteroatoms (N, S) and metal elements (Ni, V) in asphaltene will seriously interfere with the refining processes .…”

Section: Introductionmentioning

confidence: 99%