Molecular structure and size of asphaltene and preasphaltene from direct coal liquefaction

Wang, Zhicai; Yan, Gao; Shui, Hengfu; Ren, Shibiao; Pan, Chunxiu; Kang, Shigang; Lei, Zhiping; Zhao, Zhijun; Hu, Jingchen

doi:10.1016/j.fuproc.2015.03.015

Cited by 24 publications

(15 citation statements)

References 33 publications

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“…Moreover, the position and shape of these absorption peaks received the influence of hydrogen bonds originating from the O−H or N−H functional groups. 2,39 Nevertheless, it was suggested that the peaks located at around 3443 cm −1 in oil sand bitumen, its resins, and asphaltenes were mainly related to the O−H functional groups, in view of the relatively high content of oxygen compared to that of nitrogen (Table 3) in these samples. It was noticed that the peaks near 3443 cm −1 were significantly observed in the IR spectra of oil sand bitumen, resins, and asphaltenes but absent in those of aromatics, implying that the number of species and the amount of polar functional groups in these three samples were both larger than those in saturates and aromatics.…”

Section: Resultsmentioning

confidence: 98%

Thermal Cracking Characteristics and Kinetics of Oil Sand Bitumen and Its SARA Fractions by TG–FTIR

et al. 2017

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The thermal cracking process of oil sand bitumen was investigated via studying the thermal cracking behaviors and online-gas-releasing characteristics of its SARA fractions (saturates, aromatics, resins, asphaltenes) by using TG−FTIR. The results showed that the asphaltenes contributed the most to coke formation of oil sad bitumen according to its largest weighted coke yield compared with that of others. The online FTIR analysis for the gases evolved from the thermal cracking process of oil sand bitumen and its SARA fractions indicated that the gaseous products in the main reaction stage showed more complex composition than those in the volatilization stage, and predominantly consisted of CO 2 , CO, methane, ethylene, other light alkanes and olefins, light aromatics, and hydrogen sulfide. Moreover, the release behaviors of typical gaseous products (CO 2 , CO, methane, ethylene, and light aromatics) for oil sand bitumen and its SARA fractions were different due to the different composition and structure. The thermal-cracking kinetic parameters of oil sand bitumen and its SARA fractions were determined using the iso-conversional Friedman procedure at heating rates of 10 to 800 K/min. The activation energy of oil sand bitumen ranging from 93.74 to 215.99 kJ/mol in the whole thermal cracking process fell in between that of aromatics and resins. The variation of activation energy with the conversion rate for oil sand bitumen during the thermal cracking process was influenced by the interaction between SARA fractions.

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Section: Resultsmentioning

confidence: 98%

Thermal Cracking Characteristics and Kinetics of Oil Sand Bitumen and Its SARA Fractions by TG–FTIR

et al. 2017

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“…In addition, it has been confirmed that it is not easy to stabilize in air if the softening point (SP) of the precursor is lower than 200 °C . As an important thermoplastic component derived from CLR, asphaltene (CLRA) also faces such issue. , Taking into consideration the SP of the CLRA (108 °C, much lower than 200 °C), how to solve the stabilization of the CLRA properly is thought to be a key role for the preparation CLRA-based carbon nanofibers (CLRACF) film. However, there are yet few reports about this aspect.…”

Section: Introductionmentioning

confidence: 99%

Coal Liquefaction Residues Based Carbon Nanofibers Film Prepared by Electrospinning: An Effective Approach to Coal Waste Management

Xiao

Tian

Yang

et al. 2019

ACS Sustainable Chem. Eng.

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As a major byproduct of direct coal liquefaction, coal liquefaction residue (CLR) waste is environmentally harmful but also valuable. Considering environmental and economic efficiency, exploiting these wastes as electrodes for new generation energy storage devices will increase the economic value and decrease environmental pollution synchronously. In this regard, CLRs are used to prepare carbon nanofibers film for supercapacitors via electrospinning followed by HNO 3 preoxidization, air stabilization, and carbonization processes for the first time. The influences of HNO 3 preoxidization over the formation of fiber morphology, textural structure, surface chemistry, and electrochemical performance are investigated. Our work demonstrates that HNO 3 preoxidization can enhance the content of the heteroatom of the as-spun nanofibers and promote the polymerization of the asphaltene (CLRA) molecular during air stabilization, leading to the changes of the thermal behaviors and thus avoiding the fibers melting successfully. The results show that the obtained sample exhibits a 3D nonwoven network with an average diameter of 200 nm, good flexibility, high content of nitrogen, and large specific surface area. Owing to these merits, the as-obtained sample shows high specific capacitance, excellent rate capability (143 F g −1 at 100 A g −1 ), and long lifespan (98% of its initial capacitance after 10 000 cycles) as supercapacitor electrode.

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“…The presence of asphaltenes in crude oil can affect the production, transport, and refining of oil. Indeed, the absence of a protocol for handling the asphaltenes constitutes a major challenge of the petroleum industry. − ,− Although mass spectrometry − has played an important role in defining the properties of these complex materials, the molecular structures were poorly understood until recently when atomic force microscopy (AFM) combined with scanning tunneling microscopy was used to obtain atomic-scale resolution of asphaltenes . These results confirmed the considerable body of evidence that most asphaltenes can be described as island structures in which a common core of condensed aromatic rings is the dominant architecture. , Attractive interactions between the aromatic cores lead to a disordered stacking (flocculation) of 10 or fewer molecules.…”

Section: Introductionmentioning

confidence: 94%

“…Heteroatoms include nitrogen, sulfur, and oxygen. Low levels of nickel and vanadium are also frequently associated with the asphaltenes. − They are defined by their insolubility in n -pentane or n -heptane and their solubility in toluene . The presence of asphaltenes in crude oil can affect the production, transport, and refining of oil.…”

Section: Introductionmentioning

confidence: 99%

Birch Reduction of Asphaltenes. Synthesis of Hydroasphaltenes

Billups¹,

Verma²,

Brinson³

et al. 2019

Energy Fuels

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Reduction of Ecuadorian asphaltenes by lithium in liquid ammonia (Birch conditions) yields asphaltene salts that can be protonated by tert-butyl alcohol to yield deflocculated hydroasphaltene. Studies were carried out using asphaltenes from both low-and high-viscosity oils. The dimensions of the hydroasphaltenes were determined by atomic force microscopy. Relative to the starting asphaltene, the nominal asphaltene aggregate height of the low-viscosity asphaltene 1 was reduced from 1.3 to 0.7 nm, indicating that the asphaltene was fully exfoliated. The height of the high-viscosity asphaltene 2 was reduced from 4 to 2 nm. 13 C nuclear magnetic resonance of the Birch-reduced asphaltenes shows a reduction in aromaticity from 49 to 46%, indicating that a low level of hydrogen was added to the aromatic core during the Birch reduction.

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Molecular structure and size of asphaltene and preasphaltene from direct coal liquefaction

Cited by 24 publications

References 33 publications

Thermal Cracking Characteristics and Kinetics of Oil Sand Bitumen and Its SARA Fractions by TG–FTIR

Thermal Cracking Characteristics and Kinetics of Oil Sand Bitumen and Its SARA Fractions by TG–FTIR

Coal Liquefaction Residues Based Carbon Nanofibers Film Prepared by Electrospinning: An Effective Approach to Coal Waste Management

Birch Reduction of Asphaltenes. Synthesis of Hydroasphaltenes

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