The behavior of free radicals during the carbonization of anthracite briquette

Zhao, Yuqiong; Wei, Yongyong; Wang, Qi; He, Shouqi; Wang, Ying; Zhang, Yongfa

doi:10.1016/j.fuel.2020.118856

Cited by 10 publications

(1 citation statement)

References 35 publications

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“…Thus, what is the fundamental difference in elemental contents and carbon nanostructural characteristics between them? Currently, many attempts have been made to implement lower-rank coal (brown coal and sub-bituminous coal) and higher rank coal (anthracite) conversion to replace the coke derived from bituminous coals in various applications. − This indicates that investigating the mechanism of the thermal behavior differences between noncaking and caking coal is of great significance for achieving optimized utilization of coal for enhanced efficiency and enlarging the coking coal resources …”

Section: Introductionmentioning

confidence: 99%

Inspired by the Optical Properties of Char and Coke: A Study on Differences between Them from Perspectives of Organic Elemental Contents and the Carbon Nanostructure

Guo,

Tang,

Schobert

et al. 2024

Energy Fuels

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Caking coal and noncaking coal show significantly different behaviors during thermal conversion processes. Inspired by the optical properties of chars and cokes derived from noncaking and caking coals, respectively, under four different pyrolysis conditions, elemental analysis (EA), Fourier transform infrared (FTIR), CP/MAS solid-state 13 C nuclear magnetic resonance (CP/MAS 13 C NMR), Raman spectroscopy, X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HRTEM) were jointly employed to investigate and compare their organic element contents and carbon nanostructures. The FTIR and 13 C NMR spectra demonstrate that the 500 °C/30 min pyrolysis condition has transformed the aromatic, aliphatic, and carbonyl/carboxyl structures of various rank coals to varying degrees. Higher pyrolysis temperatures and longer residence times make it difficult to relate which raw coal the pyrolysis products are to the parent coals. Raman parameters, such as AD/AG vs A(G R + V L + V R )/AD, describe a dynamic process of coal structure evolution, indicating aromatics with 3−5 rings tend to decrease, resulting in the formation of aromatics with not less than 6 rings; moreover, higher pyrolysis temperature and longer residence time enhance the Raman parameters consistency of the chars and cokes. EA shows that during the same pyrolysis process (at least higher than 750 °C), the caking coal has a higher potential to be graphited, and the graphitization potential of semianthracite and anthracite is still higher than that of other noncaking coal. Furthermore, XRD indicates the d 002 of pyrolysis products derived from caking coal is about 0.34−0.35 nm, which is generally smaller than that from noncaking coal, larger than 0.35 nm. HRTEM images reveal a direct observation of the carbon nanostructure in chars and cokes, illustrating that the carbon nanostructure derived from caking coal has a flatter arrangement while that from noncaking coal has a curlier arrangement. Oxygen is considered one of the factors that inhibits the alignment of carbon nanostructure evolution.

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