构建和解析煤炭分子模型，有助于深入了解其微观结构与反应规律。首先，运用元素分析、傅里叶红外光谱（FTIR）、固体核磁共振碳谱（¹³C-NMR）、X射线光电子能谱（XPS）等技术，结合分子模拟，全面且系统地对准格尔地区的褐煤分子结构进行了研究。然后，构建了准格尔褐煤的二维结构模型；利用Material Studio 2020软件对平面模型实施了几何优化处理，在加氢饱和、结构优化和退火动力学模拟后，化学键扭曲，能量显著降低，生成三维结构模型。最后，进一步进行密度模拟，通过势能与密度的关系，确定最优密度并构建聚集态模型。研究结果表明：准格尔褐煤的桥碳和周碳比值（$ Xmathrm{_{BP}} $）为0.12，芳香结构以苯环为主，氧原子主要以酚羟基形式存在，而氮元素则主要分布在吡咯结构中，由于硫含量较低，模型中忽略了硫的影响；煤结构的稳定性主要由扭转能和范德华能主导；确定模型最优密度为1.1 g/cm³，与实测值吻合，将40个大分子模型组装为聚集态结构，并通过分子力学和动力学优化，显示分子间与分子内作用力导致芳香层片扭曲变形，形成较为杂乱的结构。该研究通过密度模拟提升了模型的可靠性，为从分子尺度深入探讨褐煤特性奠定了坚实的理论基础。

Molecular structure modeling and analysis can help gain a deeper insight into microscopic structure and reaction mechanism of coal. A systematic and comprehensive study is made of the molecular structure of the lignite of Jungar Mining Area by using the technologies like elemental analysis, Fourier-transform infrared spectroscopy (FTIR), solid-state nuclear magnetic resonance carbon spectroscopy (¹³C-NMR), and X-ray photoelectron spectroscopy (XPS) as well as molecular simulations, and building of the two-dimensional structure model of the coal. Through geometric optimization of the plane model using the software Material Studio 2020 as well as hydrosaturation treatment, structural optimization and annealing dynamics simulation, a 3D model is generated as a result of twisting of chemical bonds and significantly reduced energy. The density simulation is further carried out to determine the optimum density and construct an aggregate model based on relation of potential energy with density. As indicated by study result, the optimum density of the lignite $ X_{{mathrm{B}} {mathrm{P}}} $ is 0.12, and benzene ring dominates its aromatic structure; the oxygen atoms exist mainly in form of phenolic hydroxyl group while nitrogen elements are mainly distributed in the pyrrole structure; as the lignite has a comparatively low sulfur content, the influence of sulfur is ignored in the model; the tortional energy and Van der Waals enegy play a dominate role in the stability of structure of lignite; the model-determined optimum density is 1.1 g/cm³ which is in good agreement with the actually measured value; as revealed by the aggregate structure model fitted up with altogether 40 micromolecular models, and by the results of optimization of molecular mechanics and dynamics, the distortion and deformation of the aromatic lamellae are attributed to the interaction of intermolecular and intramolecular forces — a factor causing the lignite to become disordered in molecular structure. Through density simulation made in the paper, the reliability of the model is improved, and the research findings provide a solid theoretical basis for in-depth study of characteristics of lignite from the molecular perspective.