| Coal is an important driving force of China’s economic development. With the continuous improvement of our industry and the rapid rise of living standards, no matter utilization of resources or the deep processing requirements of primary energy, we set a higher goal of coal mining and utilization, especially. To solve the above problems, we have to study deeper for coal molecular structure. Only do we fundamentally recognize and understand the features of coal molecular structure, and maximize the value of coal. We chose Malan no.8coal of XiShan Taiyuan ShanXi which is on the turning point in coalification, and provide theoretical guidance for studying the metamorphic mechanism of coal.We chose MaLan No.8coal as sample, and in turn use FTIR、XRD、 HRTEM、XPS and13CNMR etc equipments for analyzing the coal. By analyzing the FTIR spectrum, we characterize the mode of occurrence of carbon and oxygen elements. Through analyzing the XRD spectrum, we get dates which are the parallel aromatic layers lamellar spacing (d002), the effective height of a pile of aromatic nuclei in the vertical direction (Lc), the average diameter of the pile cluster aromatic ring plies (La) and the average number of layers piled aromatic clusters (Nave)-We can directly observe the aromatic layers using HRTEM. Then using relative Matlab software, we extract the aromatic layers from the pictures of HRTEM and statistics the dates and get crystal lattice parameters. Compare the result with the same sense of XRD, and then correct analytical results. We analyze the XPS spectrum and characterize the mode of occurrence of nitrogen、sulfur and oxygen elements, and then quantitatively analyze the proportion of each form. Also, after analyzing the13CNMR spectrum, we qualitatively and quantitatively characterize the mode of occurrence of carbon and oxygen elements. The conclusion is that, in the macromolecular structure model, there are mainly methyl, methylene, methane and the ratio is about5:2:3. In the structure model, the aromatic carbons are main types of pyrrole, pyridine, thiophene, benzene, naphthalene, anthracene, phenanthrene, four-membered aromatic ring. Based on various elements analytical information obtained from the above, we use the ACD/CNMR software of carbon prediction to construct the coal macromolecular structure model, then increasing the line width in the gNMR software, comparing spectrum with13CNMR, if the spectrum matched better, we get the coal macromolecular structure model. Coal macromolecular structure models are optimized for molecular mechanics and dynamics annealing which is took out by Forcite module of MS software, and then we get the minimum energy structure model which is the most stable. In addition, using VAMP module calculates the bond length bond order and electrons charge in structure model. It is that the effect of aromatic functions to aliphatic chain results in chemical bonds becoming relatively stable. Nevertheless, the more leaving aromatic functions, the bond length longer and the bond order smaller. In the paper, we explore the relative of density and energy of Malan No.8coal, and obtain the density value when the energy is the minimum which it is about1.3g/cm3. We have constructed unit cells which respectively consist of one, two, three and four structure model. Exploring the new method for understanding aromatic structure in coal and the conclusion is simulation calculation and experimental test value are deviation.Through analyzing the experiment and simulation calculation, not only we deeply cognize the coal, but develop new method and ideas to studies different coal samples, also providing a theoretical guide for deep processing and efficient use of coal. |
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