Li Qi, Qin Yujin, Ren Shaokui
College of Environment and Civil Engineering, Chengdu University of Technology, Chengdu, 610059, China.
Wenzhou University of Technology, Wenzhou, 325006, Zhejiang, China.
Sci Rep. 2023 Sep 1;13(1):14365. doi: 10.1038/s41598-023-40753-x.
Understanding the molecular structure characteristics of coal at the molecular level is of great significance to realize the rational utilization and efficient conversion of coal. This paper gives insights into the acquisition of characterization parameters of coal molecular microstructure by testing and analyzing the long flame coal from Qinggangping (QGP) Coal Mine through proximate analysis, ultimate analysis, vitrinite reflectance determination, fourier transform infrared Spectroscopy test (FTIR), X-ray photoelectron epectroscopy test (XPS), carbon nuclear magnetic resonance (C-NMR) and X-ray diffraction (XRD). The results show that benzene rings in the QGP coal are mainly connected in a disubstituted way, accounting for 36.48%. Oxygen atoms mainly exist in the oxygen-containing functional groups such as the ether C-O, C=O and -COO. Aliphatic hydrocarbons in the aliphatic group are mainly of symmetrical -CH stretching vibration. Hydroxyl groups are mainly composed of OH-OH and OH-O hydrogen bonds, accounting for 29.21% and 21.53%, respectively. Nitrogen atoms exist in the form of CHN. The coal molecular is mainly of aromatic carbon structure, where the ratio of bridge aromatic carbon to peripheral carbon is 0.198. There are benzene, naphthalene and anthracene in 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 finally determined as CHONS. On this basis, the two-dimensional and three-dimensional macromolecular models are constructed with the assistance of simulation software. In addition, the C-NMR spectra and densities of the constructed molecular models are calculated, which verifies the rationality of the models. The macromolecular structure model of bituminous coal constructed in this study provides a theoretical model basis for the optimal surfactant.
在分子水平上理解煤的分子结构特征对于实现煤的合理利用和高效转化具有重要意义。本文通过对青岗坪（QGP）煤矿的长焰煤进行工业分析、元素分析、镜质体反射率测定、傅里叶变换红外光谱测试（FTIR）、X射线光电子能谱测试（XPS）、碳核磁共振（C-NMR）和X射线衍射（XRD）等测试分析，深入了解了煤分子微观结构表征参数的获取。结果表明，QGP煤中的苯环主要以二取代方式连接，占36.48%。氧原子主要存在于醚C-O、C=O和-COO等含氧官能团中。脂肪族中的脂肪烃主要为对称的-CH伸缩振动。羟基主要由OH-OH和OH-O氢键组成，分别占29.21%和21.53%。氮原子以CHN的形式存在。煤分子主要为芳香碳结构，其中桥连芳香碳与周边碳的比例为0.198。煤分子结构中有苯、萘和蒽，前两者起主导作用。根据分析结果，最终确定QGP煤的分子式为CHONS。在此基础上，借助模拟软件构建了二维和三维大分子模型。此外，计算了构建的分子模型的C-NMR光谱和密度，验证了模型的合理性。本研究构建的烟煤大分子结构模型为优化表面活性剂提供了理论模型依据。
