分子力学和分子动力学方法研究不同变质程度烟煤的分子结构

采用分子力学和分子动力学模拟方法 ,研究了不同变质程度烟煤的三维分子构型和能量参数。结果表明 :随变质程度的增加 ,煤分子内平行的芳香片层结构增大。不同变质程度烟煤分子在团聚前后的成键相互作用能仅略有变化 ,其中扭转能Et 的变化相对较为显著 ,并且扭转能随煤阶的增加呈逐渐减小的趋势。非成键作用能 ,特别是超过三个原子的范德华作用能 ,是煤中的重要相互作用能 ,是模型分子团聚的重要驱动力 ,对于烟煤分子聚集状态的形成起着决定性的作用。同时随煤阶的升高 ,超过三个原子的范德华作用能逐渐增加。模型分子的总势能随煤阶的变化呈两头高、中间低的趋势 ,与煤的一些宏观物理性质有一定的相一致性。

MODELING OF MOLECULAR STRUCTURE OF VARIOUS BITUMINOUS COALS BY MOLECULAR MECHANICS AND MOLECULAR DYNAMICS

Molecular modeling has been used to study the three-dimensional structure and the energies of various bituminous coals by molecular mechanics and molecular dynamics.These studies demonstrate that the aromatic rings in stabilized molecular structures are tended to parallel with the increase of coal rank.In particular, non-bonding energies especially van der Waals interactions appear to be powerful driving forces for the formation of three-dimensional structure.However, there are only slightly changes of bonding energies after folding of coal structure models.Additionally, the tendency in the changes of total energy in the models with various coal rank is in good agreement with the changes of coal physical properties observed experimentally, which may require further study.