The characteristics and mechanism for the formation of tars from low temperature pyrolysis of lignite

Xu, Ying; Wang, Jiming; Zhang, Xiaodi; Zhang, Yongfa

doi:10.1016/j.joei.2021.09.014

Cited by 11 publications

(4 citation statements)

References 24 publications

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“…In the last stage, the loss time is 16.80 min, and the loss mass values are only 1.06 and 0.50%, in which the polycondensation of some thick-ring compounds occur. The final residual carbon yield of SA is only 0.24%, whereas those of AR and RE are 8.67 and 15.94%, respectively, indicating that during pyrolysis, SA does not condensate easily and changes into volatile products almost completely while RE condensates easily to undergo coking at high temperatures …”

Section: Resultsmentioning

confidence: 98%

“…The final residual carbon yield of SA is only 0.24%, whereas those of AR and RE are 8.67 and 15.94%, respectively, indicating that during pyrolysis, SA does not condensate easily and changes into volatile products almost completely while RE condensates easily to undergo coking at high temperatures. 26 2.2.4. FT-IR Analysis of Group Components.…”

Section: Elemental Analysis Of Group Componentsmentioning

confidence: 99%

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Molecular Characteristics of Jimusaer Shale Oil from Xinjiang, China

Chen

Liu

et al. 2022

ACS Omega

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Increasing attention is currently obtained by the exploitation and utilization of unconventional energy sources globally. Jimusaer shale oil (JSO) was prepared by dry distillation from oil shale in Jimusaer, Xinjiang, China. Using n-heptane and toluene as solvents, saturate (SA), aromatic (AR), resin (RE), and asphaltene (AS) samples were produced from JSO. Samples were subsequently analyzed by elemental analysis (EA), thermogravimetric analysis (TG-DTG), infrared analysis (FT-IR), high-performance gel chromatography (GPC), and nuclear magnetic resonance (1H-NMR and 13C-NMR). In terms of basic properties, element content, classification of combustible minerals, and refining performance, JSO, which has a high H/C value, low carbon residue yield, low metal content, and excellent refining-processing performance, is considered a high-quality shale oil compared with the shale oil produced in other areas. The refining performance of JSO is even comparable with petroleum. According to column chromatography, the contents of SA, AR, RE, and AS in JSO are 54.32, 18.86, 25.81, and 1.01%, respectively. The results of FT-IR and NMR (1H-NMR and 13C-NMR) demonstrated that the chain alkane or aromatic cycloalkyl substituents of SA, AR, and RE decrease sequentially, while the number of aromatic rings and cycloalkane rings and the degree of condensation increase sequentially. These results indicate that the chain alkanes with a small number of cycloalkanes are the main component of SA. The AR and RE contain more thick-ring aromatic hydrocarbons. According to GPC, the molecular weight (M n) of JSO is 845 g·mol–1, and those of SA, AR, and RE are 702, 1107, and 2218 g·mol–1, respectively. The estimated molecular formulas (M af) of JSO, SA, AR, and RE, which were calculated based on the combined results of GPC and EA, are C57.91H115.60O1.38N0.79S0.04, C48.02H101.79O0.69N0.85S0.03, C76.96H137.16O1.08N1.87S0.09, and C156.24H247.75O1.46N4.42S0.32.

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Section: Resultsmentioning

confidence: 98%

Section: Elemental Analysis Of Group Componentsmentioning

confidence: 99%

Molecular Characteristics of Jimusaer Shale Oil from Xinjiang, China

Chen

Liu

et al. 2022

ACS Omega

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“…Studies have shown that concentrations of phenols, BTEX, and PAHs decrease with increasing pressure. Other results showed that the yield and viscosity of tar increased with the increase in heating rate and pyrolysis temperature [48]. In addition, the tar yield under a hydrogen atmosphere was observed to be higher than that under a nitrogen, carbon dioxide, methane, and carbon monoxide atmosphere.…”

Section: Effect Of Gasification Agent On Tar Concentrationmentioning

confidence: 94%

“…Wiatowski et al [46,47] carried out a series of measurements on the yields, composition, heating value, density, and viscosity of tar samples in the UCG trial at Mine "Wieczorek" and "Barbara" (Poland). Xu et al [48] investigated the relationship between tar behaviors, including its yields, viscosity, and composition at low pyrolysis temperature, and tar formation in a fixed bed reactor. Xu et al [49] found the tar yield decreased with the increase in pyrolysis temperature on a high-temperature tube furnace in UCG conditions.…”

Section: Effect Of Gasification Agent On Tar Concentrationmentioning

confidence: 99%

Investigation of Underground Coal Gasification in Laboratory Conditions: A Review of Recent Research

Kačur,

Laciak,

Durdán

et al. 2023

Energies

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The underground coal gasification (UCG) technology converts coal into product gas and provides the option of environmentally and economically attractive coal mining. Obtained syngas can be used for heating, electricity, or chemical production. Numerous laboratory coal gasification trials have been performed in the academic and industrial fields. Lab-scale tests can provide insight into the processes involved with UCG. Many tests with UCG have been performed on ex situ reactors, where different UCG techniques, the effect of gasification agents, their flow rates, pressures, and various control mechanisms to improve gasification efficiency and syngas production have been investigated. This paper provides an overview of recent research on UCG performed on a lab scale. The study focuses on UCG control variables and their optimization, the effect of gasification agents and operating pressure, and it discusses results from the gasification of various lignites and hard coals, the possibilities of steam gasification, hydrogen, and methane-oriented coal gasification, approaches in temperature modeling, changes in coal properties during gasification, and environmental risks of UCG. The review focuses on laboratory tests of UCG on ex situ reactors, results, and the possibility of knowledge transfer to in situ operation.

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