High-Efficiency Extraction and Modification on the Coal Liquefaction Residue Using Supercritical Fluid with Different Types of Solvents

Lin, Xiongchao; Li, Shouyi; Guo, Fenghua; Jiang, Guangce; Chen, Xujun; Wang, Yangang

doi:10.1021/acs.energyfuels.6b00326

Cited by 13 publications

(4 citation statements)

References 36 publications

(57 reference statements)

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“…Asphaltene should be separated from coal liquefaction residue to effectively utilize. Various solvents and methods were used to extract and separate asphaltene from direct coal liquefaction residue, such as cyclohexane, methanol, acetone, carbon disulfide, n -hexane, toluene, benzene, tetrahydrofuran, acetone, subcritical water, and supercritical fluid extraction . The extraction temperature, solvent physicochemical property, and solvent/solid ratio are the important factors on the separated asphaltene molecular weight distribution and chemical composition.…”

Section: Introductionmentioning

confidence: 99%

“…Various solvents and methods were used to extract and separate asphaltene from direct coal liquefaction residue, such as cyclohexane, methanol, acetone, carbon disulfide, n-hexane, toluene, benzene, tetrahydrofuran, acetone, 10 subcritical water, 11 and supercritical fluid extraction. 12 The extraction temperature, solvent physicochemical property, and solvent/ solid ratio are the important factors on the separated asphaltene molecular weight distribution and chemical composition. The asphaltene-based carbon materials, such as porous carbon, 13−15 carbon foam, 16,17 carbon nanosheets, 18,19 carbon fibers, 20,21 doped carbon materials, and versatile composite, 22,23 have been successfully utilized in water purification, gas adsorption, electrodes, etc.…”

Section: ■ Introductionmentioning

confidence: 99%

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From Coal-Heavy Oil Co-refining Residue to Asphaltene-Based Functional Carbon Materials

Qin

Jiang

et al. 2019

ACS Sustainable Chem. Eng.

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Asphaltene-based carbon fiber, needle coke, and porous carbon nanosheets were synthesized using the extracted asphaltene from coal-heavy oil co-refining residue. Asphaltene with high average molecular weight and aromaticity is considered proper to be polymerized or crosslinked, and is a high-performing precursor to synthesize carbon materials. It can be transferred into pitch after pyrocondensation polymerization; the resultant asphaltenebased carbon fiber with a tensile strength of 0.92 GPa was obtained via spinning, preoxidization, and carbonization. While high graphitized needle coke was formed when asphaltene underwent thermal polycondensation, delayed coking, and carbonization, it provided a facile route to produce needle coke from asphaltene. A porous carbon nanosheet with a high surface area of 1717 m 2 /g and pore volume of 0.94 cm 3 /g was synthesized using asphaltene as carbon precursor, melamine as nitrogen resource, and molten salt as template; the porous carbon nanosheet showed high CO 2 adsorption amount and outstanding adsorption selectivity for CO 2 -N 2 and CO 2 -CH 4 . It indicated that asphaltene was an excellent precursor to prepare functional carbon materials for its adjustable molecular weight distribution, high aromaticity, controllable thermal condensation, and easy graphitization. It provided an effective strategy to tailor solid residue from coal and heavy oil co-refining and developed directional conversion or utilization of asphaltene.

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Section: Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

From Coal-Heavy Oil Co-refining Residue to Asphaltene-Based Functional Carbon Materials

Qin

Jiang

et al. 2019

ACS Sustainable Chem. Eng.

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“…Xu et al 16 used direct thermal polycondensation of different components in coal tar pitch to prepare mesophase between 400 and 460 °C and found that the n-heptane-soluble component tended to form mesophase with wide-range anisotropic phase, while the n-heptane-insoluble-toluenesoluble component and toluene-insoluble-pyridine-soluble component tended to produce mosaic and streamlined textured mesophase with anisotropic phase contents above 90%. Lin et al 17 found that the extraction of coal liquefaction residues using supercritical fluids facilitated the formation of 100% mesophase, and the streamline texture was significantly improved compared to the mesophase prepared from raw coal liquefaction residues.…”

Section: Introductionmentioning

confidence: 99%

Correlation of Mesophase Properties with Molecular Structures of Pitches from Different Sources

Qi,

Huang,

Baker

et al. 2024

Energy Fuels

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In this paper, the molecular structures of vacuum residue (VR), coal liquefaction pitch (CLP), and coal tar pitch (CTP) are presented in detail, in order to explore their connection with mesophase properties. It is found that the H/C atom ratio of VR is as high as 1.32 because of abundant aliphatic structures. Its average aromatic ring number (R A ) is only 3.88, and some of its internal aromatic rings are connected by bridged bonds. The mesophase pitch from VR (MP-VR) has a low mesophase content of 28.28−40.7% and is mostly of fiber texture. CTP has a degree of aromaticity (f a ) of 0.90 and an R A of 10.65. The polycyclic aromatic molecule has only a few alkyl substituents at the periphery, resulting in a low H/C atom ratio of 0.56. The mesophase pitch from CTP (MP-CTP) has a mesophase content of 31.5−53.9% and has a distinct mosaic texture. CLP has the largest average molecular structure unit size, with an R A of 12.33 and a large degree of condensation. It contained certain cycloalkane structure and methyl substituents. The mesophase pitch from CLP (MP-CLP) has a mesophase content of 43.3−54.4% and contains abundant fiber and flaky textures. The regular and compact lamellar arrangement of planar aromatic macromolecules gives MP-CLP better graphitization properties, thermal stability, and rheological properties than MP-VR and MP-CTP.

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“…At present, the pretreatment methods for asphalt, including extraction–sedimentation, centrifugation, flash-condensation, extraction–hydrogenation, solvent flocculation, supercritical extraction, etc., have their own advantages and disadvantages. − For example, the process of extraction hydrogenation enhanced the coking property of asphalt and easily caused the catalyst deactivation . Similarly, the use of flocculants in asphalt pretreatment would introduce new impurities into the product and increase operating costs .…”

Section: Introductionmentioning

confidence: 99%

Optimizing the Preparation Process of Refined Asphalt Based on the Response Surface and Preparation of Needle Coke

Wei,

Jiang

2024

ACS Omega

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Refined asphalt was prepared by solvent extraction sedimentation based on the response surface design, using washing oil and kerosene as solvents and the coal tar pitch as raw materials. The mathematical models of the refined asphalt yield, quinoline insoluble (QI) content, ash content, solvent-to-oil ratio, aromaticto-aliphatic hydrocarbon ratio, extraction temperature, and sedimentation time were proposed, analyzing the influence of each factor and their interactions on the response values. Therefore, the optimal combination of preparation process parameters and better operation window was obtained by optimizing the experiment. Meanwhile, refined asphalt with high QI content and low QI content was selected as raw material, and the needle coke was prepared through the process of carbonization and calcination. The influence of QI content on the composition and the structure of green coke and needle coke was investigated by X-ray diffraction (XRD), Raman spectra, and polarizing microscopy characterizations. The results showed that the solvent-to-oil ratio is 1.2, aromatic-to-aliphatic hydrocarbon ratio is 1.1, sedimentation time is 2 h, and extraction temperature is 110 °C, resulting in the yield of refined asphalt being 76%, QI content being less than 0.1%, and ash content being less than 0.05%, which meets the requirement of the high-quality needle coke. Otherwise, refined asphalt with lower QI content easily generates a mesophase with more fibers and a large structure in the thermal conversion process, and the corresponding green coke and needle coke have a relatively regular carbon microcrystalline structure.

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High-Efficiency Extraction and Modification on the Coal Liquefaction Residue Using Supercritical Fluid with Different Types of Solvents

Cited by 13 publications

References 36 publications

From Coal-Heavy Oil Co-refining Residue to Asphaltene-Based Functional Carbon Materials

From Coal-Heavy Oil Co-refining Residue to Asphaltene-Based Functional Carbon Materials

Correlation of Mesophase Properties with Molecular Structures of Pitches from Different Sources

Optimizing the Preparation Process of Refined Asphalt Based on the Response Surface and Preparation of Needle Coke

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