The structural alignment of coal and the analogous case of Argonne Upper Freeport coal

Mathews, Jonathan P.; Sharma, Atul

doi:10.1016/j.fuel.2011.12.046

Cited by 106 publications

(101 citation statements)

References 53 publications

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“…Hence, when used in combination, these can be more 118 informative and can also be used as a means of checking consistency 119 to some degree. Results from these techniques have shown that the 120 molecular skeleton of bituminous, and higher rank coals consist 121 mainly of aromatic sheets or layers [9][10][11][12][13][14][17][18][19]24,27,30,31]. 122 The improved understanding of the chemical structure of coal 123 at the molecular level that has resulted from these new investiga-124 tions has led to the development of refined coal molecular struc- 125 tures, so that they could be more effectively used in the 126 prediction of coal behaviour (reactivity and reaction mechanisms) 127 in its various utilisation processes [27,[32][33][34][35][36][37][38][39][40].…”

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confidence: 99%

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Chemical–structural properties of South African bituminous coals: Insights from wide angle XRD–carbon fraction analysis, ATR–FTIR, solid state 13 C NMR, and HRTEM techniques

Okolo

Neomagus

Everson

et al. 2015

Fuel

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confidence: 99%

“…HRTEM. The molecular structural features of coals have 440 been studied by the HRTEM image analysis technique, using the 441 acquired high resolution fringe images[3,[9][10][11][12]17,24,27,30]. The442 HRTEM images of the coal samples were acquired from a 200 kV 443 Tecnai F20 FEGTEM and captured using a Gatan Inc. ORIUS™ CCD 444 camera (Model 895).…”

mentioning

confidence: 99%

Chemical–structural properties of South African bituminous coals: Insights from wide angle XRD–carbon fraction analysis, ATR–FTIR, solid state 13 C NMR, and HRTEM techniques

Okolo

Neomagus

Everson

et al. 2015

Fuel

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301

130

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“…However, the orientation and ordering degree of the aromatic layers, regarded as important spatial position information on the kerogen structure, has been ignored in most of the existing 3D kerogen models (Vandenbroucke and Largeau, 2007;Bousige et al, 2016;Huang et al, 2017). Some studies have been performed on the structural alignment of coal (Mathews and Sharma, 2012;Romero-Sarmiento et al, 2014). Due to the complexity and heterogeneity of kerogen, it is still a big challenge to build a realistic 3D kerogen model considering the orientation of the aromatic layers.…”

Section: Molecular Structure Of Kerogen In the Longmaxi Shale: Insighmentioning

confidence: 99%

“…The white fringes in these micrographs represent the aromatic rings (Niekerk and Mathews, 2010). All the fringes have been assigned to different ring size groups that were false colored according to the assignments established by Mathews and his coworkers (Niekerk and Mathews, 2010;Mathews and Sharma, 2012).…”

Section: High-resolution Transmission Electron Microscopy (Hrtem) Expmentioning

confidence: 99%

Molecular Structure of Kerogen in the Longmaxi Shale: Insights from Solid State NMR, FT‐IR, XRD and HRTEM

Wang

Zhu

Liu

et al. 2019

Acta Geologica Sinica (Eng)

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Kerogen plays an important role in shale gas adsorption, desorption and diffusion. Therefore, it is necessary to characterize the molecular structure of kerogen. In this study, four kerogen samples were isolated from the organic-rich shale of the Longmaxi Formation. Raman spectroscopy was used to determine the maturity of these kerogen samples. Highresolution transmission electron microscopy (HRTEM), 13 C nuclear magnetic resonance ( 13 C NMR) , X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy were conducted to characterize the molecular structure of the shale samples. The results demonstrate that VR eqv of these kerogen samples vary from 2.3% to 2.8%, suggesting that all the kerogen samples are in the dry gas window. The macromolecular carbon skeleton of the Longmaxi Formation kerogen is mainly aromatic (f a '=0.56). In addition, the aromatic structural units are mainly composed of naphthalene (23%), anthracene (23%) and phenanthrene (29%). However, the aliphatic structure of the kerogen macromolecules is relatively low (f al * +f al H =0.08), which is presumed to be distributed in the form of methyl and short aliphatic chains at the edge of the aromatic units. The oxygen-containing functional groups in the macromolecules are mainly present in the form of carbonyl groups (f a c =0.23) and hydroxyl groups or ether groups (f al O =0.13). The crystallite structural parameters of kerogen, including the stacking height (L c =22.84 Å), average lateral size (L a =29.29 Å) and interlayer spacing (d 002 =3.43 Å), are close to the aromatic structural parameters of anthracite or overmature kerogen. High-resolution transmission electron microscopy reveals that the aromatic structure is well oriented, and more than 65% of the diffractive aromatic layers are concentrated in the main direction. Due to the continuous deep burial, the longer aliphatic chains and oxygen-containing functional groups in the kerogen are substantially depleted. However, the ductility and stacking degree of the aromatic structure increases during thermal evolution. This study provides quantitative information on the molecular structure of kerogen samples based on multiple research methods, which may contribute to an improved understanding of the organic pores in black shale.

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“…6), 15 although many other analytical approaches have also found anisotropy. 16 Optical anisotropy is more readily apparent in transparent rather than reflectance microscopy for the younger bituminous coals. 17 For Illinois No.…”

Section: Coal As a Strained System And It Preferential Alignmentmentioning

confidence: 99%

Interactions of Illinois No. 6 Bituminous Coal with Solvents: A Review of Solvent Swelling and Extraction Literature

2015

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There has been copious research exploring the interactions between coal and various solvents either for coal structural investigations using coal swelling or industrial consideration exploring extraction yields. Here the literature is reviewed for Illinois no. 6 coal. This is the most well studied coal in existence and so offers an opportunity to reveal a wealth of information with a wide variety of solvents and extractions. This coal swells extensively (raw) in a good solvent such as pyridine (Q-factors of 2.2) and lesser degrees in benzene (Q-factor of 1.1). However if first extracted the extent of swelling can be greater. The swelling process is typically slow, sometimes taking days with anisotropic swelling being evident on the first exposure but absent from subsequent exposures. Overshoot phenomena, similar to polymer swelling, is also observed for some particles. These behaviors are related to the complex interactions of solvent diffusion and coal "relaxation" that is related to the nature of the solvent and its interactions with coal. Extraction yields are similarly varied with values ~30 wt.% (daf basis) with pyridine although greater values are obtained with two-stage, higher temperature, and exhaustive extractions. With CS 2 /NMP/H 2 O a yield as high as 70% wt.% (daf basis) have been reported at 600 K. Using light cycle oil has yields between 20 and 70 wt.% depending on consitions at 633 K. The swelling evidence supports a cross-linked structure and solvent extraction supports a considerable amount of extractable material. These statements are not necessarily in conflict.

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The structural alignment of coal and the analogous case of Argonne Upper Freeport coal

Cited by 106 publications

References 53 publications

Chemical–structural properties of South African bituminous coals: Insights from wide angle XRD–carbon fraction analysis, ATR–FTIR, solid state 13 C NMR, and HRTEM techniques

Chemical–structural properties of South African bituminous coals: Insights from wide angle XRD–carbon fraction analysis, ATR–FTIR, solid state 13 C NMR, and HRTEM techniques

Molecular Structure of Kerogen in the Longmaxi Shale: Insights from Solid State NMR, FT‐IR, XRD and HRTEM

Interactions of Illinois No. 6 Bituminous Coal with Solvents: A Review of Solvent Swelling and Extraction Literature

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