Structure characteristics and association behavior of coal and petroleum C7-asphaltenes

Du, Juntao; Zhang, Da-kui; Zhang, Min-xin; Jia, Huina; Nie, Yi; Sun, Yikai; Deng, Wei; Li, Chuan

doi:10.1016/s1872-5813(20)30051-7

Cited by 7 publications

(4 citation statements)

References 25 publications

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“…[34] The resin interacts with the polar functional groups of asphaltene through hydrogen bonding, thus adsorbing the asphaltene micelles. [35] In the range of C-H expansion vibration region of the aliphatic group, SARA have absorption peaks, and the strength and content of SARA are gradually reduced from saturate to asphaltene, which indicates that saturate contains more aliphatic hydrocarbon structure, which is consistent with the higher H/C atomic ratio in element analysis. The absorption peak strength of asphaltene in this range is lower than that of the other three fractions, which indicates that asphaltene has the structure of a low branched chain and high aromaticity.…”

Section: Ft-ir Analysissupporting

confidence: 58%

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Study on molecular structure and association behaviour of heavy subfractions of vacuum residue by an improved separation method

Tian

Han²,

et al. 2022

Can J Chem Eng

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Vacuum residue (VR) is the most complex component of crude oil. Due to the special structure of heavy subfractions, physical aggregation and chemical coking reactions easily occur through molecular force, which affects the normal processing. Therefore, in‐depth study and analysis of their composition, structure and association behaviours are particularly important. In view of the shortcomings of the traditional separation method in terms of separation accuracy, mainly including the purification of asphaltenes and the poor separation of resins. In this paper, a reasonably improved separation method is adopted, and the multi‐stage asphaltene extraction and the multi‐stage silica gel coupling separation are carried out innovatively, which achieves a high yield of 99% while ensuring the separation accuracy. The samples were characterized by elemental analysis (EA), gel permeation chromatography (GPC), Fourier‐transform infrared spectroscopy (FT‐IR), hydrogen nuclear magnetic resonance spectroscopy (1H‐NMR), X‐ray photoelectron spectroscopy (XPS), X‐ray diffraction (XRD), and scanning electron microscope (SEM) to study their structural characteristics and association behaviours. The results show that the main forms of heteroatoms in asphaltene and resin surface are C‐O‐C, C‐OH, pyridine, pyrrole, and thiophene, and the content of these substances is higher in asphaltene. Compared with resins, asphaltenes contain a more peri‐condensed aromatic structure and shorter alkyl substituent side chains. By studying the hydrogen bond and acid–base interaction, it is found that asphaltene and resin mainly contain OH‐OH, OH‐π, and OH‐ether O, of which the content of OH‐OH is the highest. Asphaltene and resin have more neutral and basic substances. These hydrogen bonds and acid–base interactions caused by heteroatoms are the main forces for the association of the heavy subfractions of the VR.

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Section: Ft-ir Analysissupporting

confidence: 58%

“…[ 34 ] The resin interacts with the polar functional groups of asphaltene through hydrogen bonding, thus adsorbing the asphaltene micelles. [ 35 ]…”

Section: Molecular Structure Characterization Of Saramentioning

confidence: 99%

Study on molecular structure and association behaviour of heavy subfractions of vacuum residue by an improved separation method

Tian

Han²,

et al. 2022

Can J Chem Eng

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“…Hydrogen bonding has been confirmed as one of the major functions in the correlation between asphaltene molecular micelles and plays a leading role in the correlation of asphaltene molecular micelles. 41 According to the research, 42 the hydrogen bond regions in the FT-IR spectra of asphaltene and resin can fit by peaks. In accordance with the order of wave number from large to small, the hydrogen bond can be divided into six types.…”

Section: Results and Discussionmentioning

confidence: 98%

Study on the Hydroconversion Law of Coal-Based Heavy Fractions with Different Catalyst Contents Based on an Improved Separation Method

et al. 2023

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Heavy fractions (e.g., asphaltene and resin) can easily be subjected to physical aggregation and chemical coking reaction through molecular force in the process of lightweight processing and use of coal tar (CT), such that the normal processing and use can be affected. In this study, hydrogenation experiments were performed by regulating the catalyst to oil ratio (COR), while the heavy fractions of the hydrogenated products were extracted based on a novel separation method (e.g., the resin with a poor separation effect and rare existing research). The samples were analyzed through Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, nuclear magnetic resonance spectroscopy, and thermogravimetric analysis. On that basis, the composition and structure characteristics of heavy fractions and the law of hydrogenation conversion were investigated. As indicated by the results, with the rise of the COR, the saturates, aromatics, resins, and asphaltenes (SARA) contents indicated the law of increasing the content of saturate, decreasing the content of other fractions, as well as sharply decreasing the content of asphaltene. Moreover, with the increase of the reaction condition, the relative molecular weight, the content of the hydrogen bonded functional groups and C–O groups, the carbon skeleton properties, the number of aromatic rings, and the stacking structure parameters were progressively reduced. In comparison with resin, asphaltene was characterized by large aromaticity and more aromatic rings, short and less alkyl side chains, as well as more complex heteroatoms on the surface of the heavy fractions. The results achieved in this study are expected to lay a solid basis for the relevant theoretical research and facilitate the industrial use process of CT processing.

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“…4 Because of the complexity of the coal structure and diversity of its properties and utilization, there is still a lack of specific research on coal types with different metamorphisms and coal compositions. 5 The classical physical structural models of coal include the Hirsch model, 6 cross-linking model, 7 host−guest model, 8 association model, 9 and Riley model. 10 Advanced characterization methods such as X-ray diffraction, 11 infrared spectroscopy, 12 nuclear magnetic resonance (NMR) spectroscopy, 13 statistics, and structural analysis 14 have been used in the structural studies of coal.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Pyrolysis Performance and Molecular Structure of Five Kinds of Low-Rank Coals in Xinjiang Based on the TG-DTG Method

Shan

Zhao

et al. 2022

ACS Omega

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Taking five coal samples (FCSs) in Xinjiang as the research object, characterizations such as proximate analysis, ultimate analysis, Fourier transform infrared (FTIR), and thermogravimetry-differential thermal analysis (TG-DTG) were carried out. The Coats–Redfern model was used to simulate pyrolysis kinetics of FCSs under different reaction orders (ROs). The results showed that except for HSBC, the R 2 of the other four coal samples are all higher than 0.9, which showed a good correlation effect. FCSs present similar reaction activation energy in the same RO and temperature range. Results of FTIR showed that the hydroxyl groups of FCSs, in the range of 3100–3600 cm–1, were mainly self-associated hydroxyl hydrogen bonds and hydroxyl π bonds, and they occupied over 63%. Among them, the pyrolysis characteristic index (D) of XBC was 4.139 × 10–6, higher than those of other samples, and it showed good pyrolysis performance. Moreover, by reducing the temperature range appropriately, the fitting results showed a better correlation effect.

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Structure characteristics and association behavior of coal and petroleum C7-asphaltenes

Cited by 7 publications

References 25 publications

Study on molecular structure and association behaviour of heavy subfractions of vacuum residue by an improved separation method

Study on molecular structure and association behaviour of heavy subfractions of vacuum residue by an improved separation method

Study on the Hydroconversion Law of Coal-Based Heavy Fractions with Different Catalyst Contents Based on an Improved Separation Method

Analysis of Pyrolysis Performance and Molecular Structure of Five Kinds of Low-Rank Coals in Xinjiang Based on the TG-DTG Method

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