Effects of the ratio of O2/C and H2O/C on sulfur release behaviors during fluidized bed gasification

Xian, Shengxian; Zhang, Haixia; Fan, Yanqi; Chai, Zhan; Zhu, Zhengwang

doi:10.1016/j.fuel.2021.120751

Cited by 5 publications

(2 citation statements)

References 22 publications

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“…Therefore, during CO 2 gasification, COS will be converted into H 2 S, while CS 2 will be converted into H 2 S and COS, with the combination with CO 2 /H 2 O. Moreover, the energy barriers for the conversion of CS 2 are low, indicating generated CS 2 will be quickly converted to COS, and thus the sequencing of gaseous sulfur is as follows: H 2 S yield > COS yield > CS 2 yield 30 .…”

Section: Resultsmentioning

confidence: 99%

Mechanism insight into the conversion between COS and thiophene during CO2 gasification of carbon-based fuels

Xian,

Xie,

et al. 2024

Sci Rep

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Thiophene is the organic sulfur with good thermal stability in carbon-based fuel, clarifying the conversion mechanism between thiophene and COS is beneficial for achieving in-situ sulfur fixation during CO2 gasification of carbon-based fuels, but the mechanism has rarely been reported. Therefore, calculations based on density functional theory were performed and 16 reaction paths were proposed in this research, clarifying the decomposition mechanism of thiophene and re-fixation mechanism of COS. The attachment of CO2 will lead to the destruction of the thiophene ring and the generation of COS, and CO2 adsorption is the rate-determined step, while the carbon atom that adjacent sulfur atom is the reaction active site. However, the energy barriers of CO2 addition reactions are lower than those of CO2 adsorption reactions, and the energy barrier of reactions occurring on the aliphatics are lower than that occurring on the aromatics. The combination of CO2 and thiophene will thermodynamically lead to the generation of COS and CO. Moreover, gaseous sulfur generated from thiophene decomposition will be converted mutually, while H2S will not be converted into COS. Furthermore, COS will be captured by char, forming solid organic sulfur. The re-fixation of COS will occur on aliphatic chains from the decomposition of aromatics.

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Section: Resultsmentioning

confidence: 99%

Mechanism insight into the conversion between COS and thiophene during CO2 gasification of carbon-based fuels

Xian,

Xie,

et al. 2024

Sci Rep

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“…Moreover, during pyrolysis, published research studies mainly focus on the decomposition mechanism of thiophene rather than the generation of thiophene. However, previous research showed that only part of sulfur decomposed had been released to the gas phase, while others would be recombined with the nascent char to form thiophene. , Zhang et al also claimed that the interaction between gaseous sulfur and char with high temperature would promote the conversion to solid sulfur. Therefore, the decomposition of thiophene during coal pyrolysis needs to be further investigated to clarify the dominant decomposition path of thiophene; meanwhile, the generation mechanism of thiophene also needs to be claimed to provide guidance for the source control of sulfur.…”

Section: Introductionmentioning

confidence: 99%

Mechanism Insight into the Conversion between H₂S and Thiophene during Coal Pyrolysis: A Theoretical Study

Xian,

Xu,

2023

ACS Omega

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Clean coal technology is the important thrust to the achievement of "carbon neutralization"; clearing the transformation mechanism of thiophene, the dominant organic sulfur species in coal, is conducive to promoting the development of sulfur removal technology. DFT calculations were performed, and 28 reaction paths were proposed in this research, clarifying the decomposition mechanism of thiophene and the fixation mechanism of H 2 S. Thiophene is pyrolyzed mainly through the hydrogentransfer reaction, which occurs at above 2000 K rather than 800 K. The hydrogen transfer between the C−C bond rather than the C−S bond causes the ring opening. Hydrogen promotes the decomposition of thiophene, which happens at 800 K, with a molar ratio of hydrogen to thiophene of 5. Therefore, thiophene is decomposed at 800 K mainly through the hydrogenation reaction that occurs at para carbons and the C−S bond, the H 2 S elimination reaction, and the generation of ethane. Furthermore, H 2 S can be converted into thiophene through the addition reaction with unsaturated hydrocarbon, or the dehydration reaction with hydroxyl or carboxyl groups. The combination between H 2 S and the aliphatic compound occurs at 800 K, which is mainly influenced by the species of the functional group rather than the composition and morphology of the carbon chain. Meanwhile, the conversion of aromatic compounds tends to the generation of aryl mercaptan rather than thiophene at around 800 K.

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Sulfur release behavior and sulfur fixation mechanism during biomass microwave co-pyrolysis of Ascophyllum and rice straw

Xu,

Chen,

Xian

et al. 2024

Bioresource Technology

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Effects of the ratio of O2/C and H2O/C on sulfur release behaviors during fluidized bed gasification

Cited by 5 publications

References 22 publications

Mechanism insight into the conversion between COS and thiophene during CO2 gasification of carbon-based fuels

Mechanism insight into the conversion between COS and thiophene during CO2 gasification of carbon-based fuels

Mechanism Insight into the Conversion between H₂S and Thiophene during Coal Pyrolysis: A Theoretical Study

Sulfur release behavior and sulfur fixation mechanism during biomass microwave co-pyrolysis of Ascophyllum and rice straw

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Effects of the ratio of O2/C and H2O/C on sulfur release behaviors during fluidized bed gasification

Cited by 5 publications

References 22 publications

Mechanism insight into the conversion between COS and thiophene during CO2 gasification of carbon-based fuels

Mechanism insight into the conversion between COS and thiophene during CO2 gasification of carbon-based fuels

Mechanism Insight into the Conversion between H2S and Thiophene during Coal Pyrolysis: A Theoretical Study

Sulfur release behavior and sulfur fixation mechanism during biomass microwave co-pyrolysis of Ascophyllum and rice straw

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Mechanism Insight into the Conversion between H₂S and Thiophene during Coal Pyrolysis: A Theoretical Study