Separately, several coal power plants have been refurbished to have the capability of burning biomass. However, there are many abandoned coal power plants still scattered across the United States that could be revived and refurbished to burn plant waste. These abandoned buildings could be put to use again, the jobs could be …Web
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Coal supplies 27% and 70% of total energy consumptions in world and China[1,2], respectively. The development of molecular configurations of coal and char can contribute to a better understanding of structure and reactivity during conversion processes. Coal undergoes the rapid loss of moisture and volatiles at high temperatures.Web
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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, …Web
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In terms of lithotype, the two bench samples selected are semibrigh coal. The photos of samples are shown in figure 1 and the descriptions of these samples are listed in table 1. Coal samples collected are from two coal seams: ... strong oxidants entered into the molecular layers of coals under the action of strong acids, and to avoid …Web
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Great pressure results in the creation of bituminous, or "soft" coal. This is the type. most commonly used for electric power generation in the U.S. It has a higher heating value than either lignite or sub-bituminous, but less than that of anthracite. Bituminous coal is mined chiefly in the Midwest & Appalachia.Web
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HRTEM micrographs and false-colored fringes of five coal samples: (a 1) XJ-1 HRTEM image; (b 1) GZ-2 HRTEM image; (c 1) SX-3 HRTEM image; (d 1) SX-4 …Web
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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 material in this article are ...Web
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Coal is a naturally occurring sedimentary carbonaceous rock composed of at least 50% organic matter by weight, and 70% carbonaceous material by volume, mostly from the diagenesis (chemical and physical alteration) of plant material in buried peat (Schopf 1956, 1966; Alpern and DeSousa 2002 ). Coal is a solid hydrocarbon .Web
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High-ash coal, also known as low-grade coal, has becomes a viable alternative in recent years to high-quality coal because available resources have become increasingly scarce due to extensive mining activity. This work aims to provide a comprehensive understanding of the structural characteristics of high-ash coal and …Web
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Therefore, the final density of the PS coking coal molecular model is 1.3 g/cm 3. According to related literature, the measured density range of coking coal is 1.15–1.50 g/cm 3. Therefore, the coal molecular densities simulated by LX and PS coking coals are reasonable. The crystal structure model is shown in Figure 6.Web
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3D structure of the coal sample (CHON) was developed by combing these smaller molecular presentations of the coal. Low energy 3-diemensional conformers of five different monomers of coal structure with the molecular formula of C 34 NO 3 H x (where x = 25, 27, 29, 31 and 33) were prepared using Ligprep tool within the framework of MS …Web
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Figure 1. An example of the structure of coal. of dead vegetation began to accumulate, becoming tightly packed and compressed, and gave rise to different kinds of coal, each with a different carbon concentration: …Web
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Rapid pyrolysis (∼10 4 K/s) experiments investigating lignite, bituminous coal and anthracite were conducted to study the effect of the thermal process on the coal structure. The interest was focused on the chemical structure variation occurring at the early stage of pyrolysis (0–500 ms) and high temperature (1173–1773 K), which includes the …Web
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From the architectural structure point of view, coal is not a crystal, but it has a crystal-like structure [20].It is mainly a two-phase structure composed of a skeleton of BSU with aromatic layers, branch chains of the hydrocarbon, and various functional groups, and low molecular weight compounds (LMWC) embedded in it as illustrated in Fig. 1.As the …Web
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Structural model of C100H79O7NS coal organic mass was obtained within density functional theory in the localized orbital basis set using the B3LYP hybrid functional. The model was compared with the known experimental data for coal of different grades and its sorption properties were studied with respect to CH4, CO2 and H2O. It has been …Web
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Reduction in diffusion coefficient with increased adsorption may be attributed to two reasons: (1) the effect of coal matrix swelling on pore size because adsorption swelling may narrow some micropore entrances and increase the resistance to diffuse the gas molecule through (Cui et al., 2004); and (2) strong repulsive force between adsorbed ...Web
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Decoupling the molecular structure from the pore structure is challenging under experimental conditions; this hinders the independent investigation of the effect of the changes in molecular structure on methane (CH 4) transport.In this study, the molecular model of coal was reconstructed based on the test results of X-ray photoelectron …Web
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The molecular model was geometrically optimized and annealed in the Forcite module of Materials Studio software, and the temperature was set at 293.15 K. Based on the optimized coal molecules, a ...Web
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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 …Web
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The molecular sieve model of coal structure considers coal as consisting of relatively light, hydrogen-rich molecules trapped in a hydrogen-poor carbon matrix (Aczel …Web
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Identification of coal and gangue is one of the important problems in the coal industry. To improve the accuracy of coal gangue identification in the coal mining process, a coal gangue identification method based on histogram of oriented gradient (HOG) combined with local binary pattern (LBP) features and improved support vector machine …Web
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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 ...Web
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Download : Download full-size image; Fig. 5. Evolution of molecular number for various gases and intermediates with different stoichiometric ratio. (a) O 2, (b) CO 2, (c) CO, (d) ... This single molecular structure with small sizes has a composition unit of coal molecule, which are important to understand the chemical bonding of HSW coal at ...Web
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Coal is highly heterogeneous in nature, and for this reason, several analytical techniques are needed for its characterization so as to accurately predict its behavior during conversion processes such as combustion, gasification, or liquefaction. Conventional analyses such as proximate analysis, ash analysis, and ash fusion temperatures assume …Web
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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.Web
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To study the generation rules of organic molecules or fragments and the generation paths of some hydrocarbon gases (C2H2/C2H4) and inorganic gases (CO2/H2O/H2/H2S) in the pyrolysis process of bituminous coal at 1000–5000 K, the ReaxFF molecular dynamics module in AMS software was used to simulate the …Web
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Coal gangue image recognition is a critical technology for achieving automatic separation in coal processing, characterized by its rapid, environmentally friendly, and energy-saving nature. However, the response characteristics of coal and gangue vary greatly under different illuminance conditions, which poses challenges to the stability of …Web
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Understanding the pore heterogeneity of tectonic coal and primary-structure coal is of great significance for predicting and preventing tectonic coal. This study adopts the low-temperature nitrogen adsorption method, mercury injection experiment, and other methods, combined with fractal theory, to quantitatively analyze the pore distribution of …Web
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Water gas formed by the reaction of coal with oxygen and steam is a mixture of CO, CO 2, and H 2. The ratio of H 2 to CO can be increased by adding water to this mixture, to take advantage of a reaction known as the water-gas shift reaction. CO ( g) + H 2 O ( g) CO 2 ( g) + H 2 ( g) Ho = -41.2 kJ/mol rxn.Web
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Carbon is an essential element in the bodies of living organisms. It is also economically important to modern humans, in the form of fossil fuels. Carbon dioxide— CO 2. . —from the atmosphere is taken up by photosynthetic organisms and used to make organic molecules, which travel through food chains. In the end, the carbon atoms are ...Web
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