Desulfurization mechanism of thiophene compounds in supercritical water

Lu, Libo; Wei, Wenwen; Liu, Fan; Cao, Wen; Jin, Hui; Chen, Yunan; Guo, Liejin

doi:10.1016/j.fuel.2023.129251

Cited by 4 publications

(1 citation statement)

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“…Yang 6 investigated the conversion mechanism of thiophene into H 2 S, and claimed that the decomposition of thiophene tended to be triggered by hydrogen transfer between adjacent carbon atoms, and further hydrogen transfer and breakage of C–S bond led to the generation of H 2 S. Liu 7 discussed the effect of steam on the thiophene pyrolysis, and reported the conversion to H 2 S was promoted by steam, because the addition of steam catalyzed hydrogen transfer and saturated the thiophene ring. Similarly, Lu 8 studied the desulfurization mechanism of thiophene compounds in supercritical water, and found out that the introduction of H 2 O promoted the breakage of C-S bond, and thus promoting the generation of H 2 S. Zhang 9 compared the decomposition pathways of 2-methylthiophene during inert and oxidizing atmospheres, and reported that the desulfurization of 2-methylthiophene is thermodynamically more favorable in oxidizing atmosphere. Valuable conclusions have been obtained in published researches, H 2 evolution and its relationship with the released sulfur have also been studied 10 – 13 , while the re-fixation of H 2 S has also been investigated in previous research 14 ,the conversion mechanism of thiophene into H 2 S in different atmospheres have been elucidated.…”

Section: Introductionmentioning

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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