A large-scale molecular model of Fenghuangshan anthracite coal
A large-scale (C 115925 H 42127 O N S) atomistic representation of Fenghuangshan anthracite was constructed using an image-guided approach informed by high-resolution transmission electron (HRTEM) micrographs. Additional structural information was obtained from solid state C NMR, XRD, laser desorption ionization mass spectra (LDIMS), XPS, …
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Coal
Coal is one of the world's most abundant sources of energy. percent fixed-carbon content and a heating value of 8,300–13,000 Btu/lb (8.8–13.7 million joules/lb). The fourth class, lignite, a soft brownish-black coal, also has a 46–60 percent fixed-carbon content, but the lowest heating value, 5,500–8,300 Btu/lb (5.8–8.8 million joules ...
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Occurrence mode and molecular structure model of
The molecular structure of coal greatly determines the chemical reactivity of coal. ... Analysis of the lattice fringe images. After the FSC sample was thoroughly crushed, it was observed under high resolution transmission electron microscope (HRTEM). The digitized HRTEM image was filtered by Fourier transform (FT) function in Digital ...
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Effect of hydroxyl position in reagent molecule on coal dust …
The graphical representation of the wetting behavior measurement system for coal dust is presented in Fig. 4.There has three parts for the system: (1) a glass jar for octanol solution, (2) a glass tube, transparent in nature and equipped with wool at the base to hold sample powder, and (3) a camera is employed to record the variation in height of …
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Understanding the molecular structure of Datong coal by …
The final 2D molecular model of Datong coal is shown in Fig. 5, with the molecular formula of C 149 H 112 O 24 N 2 and molecular weight of 2314.53. The comparison between the calculated and experimental 13 C-NMR spectra of molecular model is shown in Fig. 6 (a).
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Dynamic Simulation Based on a Simplified Model of 1/3 Coking Coal
The raw coal samples and coal samples immersed in water after drying, 2–3 mm coal particles are directly screened out, and the microstructure and morphology characteristics of raw coal and soaked coal are observed at 800 and 1600 times to understand the change in the internal structure of the two coal samples. Through image processing, the ...
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Theoretical understanding of coal char oxidation and …
Since the 1970 s, there are over 140 proposed molecular level representations or models of coal and coal char which are used to investigate the atomistic mechanism of the processes of oxidation, gasification and etc. [28]. At present, the molecular structure model of coal char is mainly constructed by the following ways as …
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THE MOLECULAR STRUCTURE OF COAL
the molecular nature of coal has been studied intensively for more than a quarter of a century, the picture which can be drawn of its molecular structure is still sketchy and …
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15.6: Coal
Figure 15.6.3 illustrates the global carbon cycle, the distribution and flow of carbon on Earth. Normally, the fate of atmospheric CO 2 is to either (1) dissolve in the …
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Molecular model and ReaxFF molecular dynamics simulation of coal
Vitrinite in coal, the mainly generating methane maceral, plays an important role in hydrocarbon generation of coal. This study aims at obtaining products formation mechanism of vitrinite pyrolysis, and hence determining the chemical bond, molecular liquefaction activity, and reactions mechanism of methane and C2–4 during pyrolysis. …
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Structures of Coal, Kerogen, and Asphaltenes | SpringerLink
Hypothetical molecular structures of humic coal, sapropelic kerogens, and asphaltenes are described, including how they change with maturity and how they have been refined over the past 75 years with advances in characterization methods. ... used atomic force and scanning tunneling microscopies to image 100 individual asphaltene …
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Pore Structure Characterization Based on the Panxi Coal Molecular …
Reconstructing the pores of coal from a molecular perspective was realized, providing a methodological basis for the study of the microscopic properties of Panxi coal. The molecular model of the Panxi coal was established by ultimate analysis, solid-state CP/MAS 13 C nuclear magnetic resonance, and X-ray photoelectron …
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The Molecular Model of Organic Matter in Coal-Measure …
The results show that whether the OM pores varied from 20 to 350 nm as obtained from FIB-SEM images or less than 10 nm as observed in the TEM images, both were of poor connectivity. ... Zeng F., Wang X. Construction and Evaluation of a Medium-Rank Coal Molecular Model Using a Hybrid Experi-mental–Simulation–Theoretical …
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Effect of surfactant on the attachment between coal particles …
The molecular structure of Daliuta coal shown in Fig. 4 (a) was built by our research team [30], [31]. The molecular weight and elemental composition of Daliuta coal are shown in the Table 2. The density of subsequent coal molecule aggregation model is 1.3 g/cm 3. Download : Download high-res image (518KB) Download : Download full …
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Structural characterization analysis and …
the coal molecular structure, and the former two chemicals play a dominating role. According to the analysis results, the molecular formula of the QGP coal is ¤nally …
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Filling–adsorption mechanism and diffusive transport
Download : Download high-res image (627KB) Download : Download full-size image; Fig. 1. Adsorption isotherms curves and characteristics of PSD of coal samples (pore size ≤100 nm). ... Fig. 3 (b) is the stable coal molecule periodic mode, with the parameters of the model lattice length, width, and height are 2.88 nm, 2.68 nm, ...
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Understanding the chemistry and physics of coal …
Abstract. This article outlines our current understanding of the structure of coal in terms of both the chemical and physical bonding processes responsible for its structural integrity …
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Structural characterization analysis and …
The coal molecular is mainly of aromatic carbon structure, where the ratio of bridge aromatic carbon to peripheral carbon is 0.198. ... The images or other third party …
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Stress degradation mechanism of coal macromolecular …
In this study, the Wender [30], [31] coal macromolecular structure model, which represents low-rank coal as C 42 H 44 O 10, was selected as the research object.This model can be conveniently studied owing to its simple molecular structure, which contains benzene rings, an ordinary six-carbon ring, oxygen-containing functional …
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The utility of coal molecular models
Introduction. Molecular models of coal have progressively populated the literature over the last 70 years. While they number in excess of 125 models, the initial purpose of many of these models was to aid the comprehension of coal. Models have developed over the years to capture variations in rank and maceral composition, but …
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Molecular structure characterization analysis and molecular …
Coal is the largest non-renewable energy as well as an important basic energy and industrial raw material. Thus, correctly understanding the molecular structure characteristics of coal has important theoretical value for realizing carbon neutralization. In this work, we clarified the molecular structure characteristics of anthracite, where the …
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Mechanism of the pore and molecular structure evolution of coal …
Fig. 2 depicts the 3-D CT models of coals under the different AMD environments. According to W. Liu et al. (2023), the 3D digital core reconstruction is linked to the spatial distribution of pores, minerals, and matrix.However, P. Liu et al. (2023) indicated that the small model size change is more sensitive to heterogeneity, while the …
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The molecular representations of coal – A review
The first liptinite-rich (Barzas) coal molecular representation was generated by Patrakov et al. [68], this structure was large (10,260 amu) consisting of copious quantities of condensed-linked (but not cross-linked) hydroaromatic rings (Fig. 1 h). Vu et al. [69] developed a 3D model of a low-rank coalified wood (Australian). This model also ...
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Molecular Structure of Coal
Download : Download full-size image; Fig. 1. Molecular weight distribution of ethylated Pocahontas coal (Sternberg et al., 1971). Sun and Burk ... It was found that the molecular weight of a coal "molecule" increases with rank, but that of the "unit structures" remains constant up to 82% C and then increases.
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Molecular Simulation of Methane Adsorption Properties of Coal …
Obvious differences exist in the structures of different coal rank coals, resulting in many differences and similarities in the amount of methane (CH4) gas adsorbed by coal and the control mechanism. In this study, we conducted adsorption simulations of three different coal rank coals in the superposition state using the Materials Studio …
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Study on the evolution characteristics of molecular surface …
For the entire coal molecule, the distributions of the positive and negative electrostatic potentials were non-uniform. Fig. 11 (c) shows the average values of the positive and negative electrostatic potentials on the coal molecule surface, providing a partial characterisation of the average adsorption capacity of the coal molecule. As depicted ...
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The molecular representations of coal – A review
The first liptinite-rich (Barzas) coal molecular representation was generated by Patrakov et al. [68], this structure was large (10,260 amu) consisting of copious …
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The interactions between fine particles of coal and …
The Mulliken atomic partial charges of bituminous coal molecule (the molecular model of bituminous coal [40], [41] as shown in Fig. 4) were distributed after the geometry optimization at the PW91/DNP level in the Dmol 3 module. Download : Download high-res image (621KB) Download : Download full-size image; Fig. 4.
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Experimental and theoretical study on molecular structure …
The molecular formula (C 130 H 73 O 21 NS) and two-dimensional molecular structure model of the HLL coal sample are determined, as shown in Fig. 5. Download : Download high-res image (172KB) Download : Download full-size image; Fig. 5. Two-dimensional molecular structure model of HLL coal.
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Model construction and optimization of coal molecular …
The molecular structure of coal is composed of macromolecules and low molecules, of which low molecules account for 20%. Low molecules have a great influence on the coal spontaneous combustion ...
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