Further discussion on the mechanism of hydrogen transfer in direct coal liquefaction

Wang, Xing-Bao; Fan, Huan-Huan; Xie, Zi-Zheng; Li, Wenying

doi:10.1016/j.cattod.2020.10.009

Cited by 16 publications

(3 citation statements)

References 29 publications

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“…Simultaneously, k 3 is higher than k 4 , indicating that the conversion rate of M 2 into PAA is faster than that of PAA into O + G. This further suggests that the conversion of PAA is the controlling step during the isothermal stage of the SL liquefaction reaction. Therefore, to improve the oil yield in the isothermal stage, it is necessary to increase the conversion rate of PAA into O + G. This can be achieved, for example, by providing a high-activity catalyst and a better hydrogen supply environment [24][25][26]. Furthermore, the residue yield (on a dry ash-free basis) of SL was 2.81% after 180 min of isothermal time, which was significantly longer than the time required for the kinetic analysis.…”

Section: Kinetic Model During the Isothermal Stagementioning

confidence: 99%

A Study on the Hydro-Liquefaction Kinetics of Shengli Lignite during the Heating-Up and Isothermal Stages under Mild Conditions

Li,

Zhang,

Huang

et al. 2024

Energies

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Studying the hydro-liquefaction kinetics of lignite contributes to optimizing the mild liquefaction process for lignite. In this paper, the direct liquefaction performance of Shengli lignite (SL) was investigated using a H2/THN system with 4 MPa of initial pressure, and reaction kinetic models were established for the heating-up stage and the isothermal stage. The result showed that the liquefaction performance of the SL was excellent, with a conversion of 62.18% and an oil and gas (O + G) yield of 29.88% at 698.15 K. After one hour of reaction, the conversion and O + G yield were 94.61% and 76.78%, respectively. During the heating-up stage, the easily reactive part of the SL was 50.07%, and it was converted directly into oil, gas, asphaltene (AS), and preasphaltene (PA) simultaneously. There was no significant secondary hydrogenation conversion of the AS and PA products. During the isothermal stage, the hard-to-react part was predominantly converted into AS and PA, while the remaining easily reactive part continue to react completely. The conversion of AS and PA into oil and gas was a rate-controlling step during this stage. The amount of unreacted coal estimated using the model calculated in the isothermal stage was 2.98%, which was significantly consistent with the experimental value of 2.81%.

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Section: Kinetic Model During the Isothermal Stagementioning

confidence: 99%

A Study on the Hydro-Liquefaction Kinetics of Shengli Lignite during the Heating-Up and Isothermal Stages under Mild Conditions

Li,

Zhang,

Huang

et al. 2024

Energies

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“…Bond dissociation enthalpies (BDE) quantify the energy required for the cleavage of covalent bonds. Wang et al showed that the bond distances and strengths have negligible correlation, and most workers prefer to use BDE in comparing bond strengths. , It was profoundly known as the BDE calculation equation BDE ( A − B ) = [ Δ f H 298 false( normalA − false) + Δ f H 298 false( normalB − false) ] − normalΔ f H 298 ( A − B ) …”

Section: Introductionmentioning

confidence: 99%

“…Wang et al showed that the bond distances and strengths have negligible correlation, 47 and most workers prefer to use BDE in comparing bond strengths. 48,49 It was profoundly known as the BDE calculation equation 50…”

Section: Introductionmentioning

confidence: 99%

Relationship between Organic Sulfur Occurrence and Coalification Stage: Insights from Thermodynamic Simulation and X-ray Photoelectron Spectroscopy

Zhu

Liu

et al. 2023

Energy Fuels

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Organic sulfur in coal can pollute the atmosphere due to the emission of SO x gas during coal combustion and utilization. Although the relative distributions of the different organosulfur functional groups change with progressive coalification (maturity), how these groups are incorporated in the macromolecule structures of coals and the role they play in the coalification process remain ambiguous. The purpose of this study, then, is to elucidate these relationships by using thermodynamic simulation with a reactive force field program, calculation of the C–S bond dissociation energies of four types of organosulfur functional groups, X-ray photoelectron spectroscopy (XPS) analysis of seven coal samples, and published data to determine the changes in the types and proportions of organosulfur functional groups in three coalification stages (0–1, 1–2, and >2% Ro). The results show that the bond stabilities follow the order Cal–S < S–S < Car–S. Disulfides and thioethers occur in lower contributions in the coalification stage of 0–2% Ro, while mercaptans present in a relatively higher proportion. The contribution of sulfone increases and exceeds a half in organosulfur at 1–2% Ro; the major role of sulfur turns from edge bond (0–1% Ro) to bridge bond (1–2% Ro) gradually. Thiophene decreases in the 0–1% Ro coalification stage and increases in relatively high proportions in the 1–2% Ro coalification stage. When the coalification stage is above 2% Ro, the contributions of sulfides, sulfone, and mercaptan decrease, while that of thiophene increases, and sulfur gradually acts as a thiophenic ring bond. These results demonstrate that the role of organosulfur in the macromolecular skeleton of coal changes with progressive coalification.

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Regulation of radicals by hydrogen-donor solvent in direct coal liquefaction

Wang

et al. 2022

Front. Chem. Sci. Eng.

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Further discussion on the mechanism of hydrogen transfer in direct coal liquefaction

Cited by 16 publications

References 29 publications

A Study on the Hydro-Liquefaction Kinetics of Shengli Lignite during the Heating-Up and Isothermal Stages under Mild Conditions

A Study on the Hydro-Liquefaction Kinetics of Shengli Lignite during the Heating-Up and Isothermal Stages under Mild Conditions

Relationship between Organic Sulfur Occurrence and Coalification Stage: Insights from Thermodynamic Simulation and X-ray Photoelectron Spectroscopy

Regulation of radicals by hydrogen-donor solvent in direct coal liquefaction

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