重质油超临界流体萃取分离窄馏分的分子模型

根据大庆减压渣油超临界流体萃取分离窄馏分的分子结构参数,在保证侧链数和平均侧链长度不变的前提下,分别构建了一系列具有相同侧链长度但侧链分布不同的分子和具有相同侧链分布但侧链长度各异的分子。利用分子力学法和分子动力学法对这些可能的分子结构进行了模拟计算,得到了全局能量最低的分子结构三维构象。对这些三维分子结构及其与全局最低能量的关系进行了分析,分别提出了定量描述不同侧链分布结构和不同侧链长度结构与分子能量关系的侧链分布因数和侧链长度因数。这两个因数与相应的分子最低总能量呈良好的线性关系。根据分子能量越低结构越稳定及分子结构存在的可能性越大的原理,确定了存在的可能性最大的重质油平均分子侧链结构。

Molecular model for super critical fluid extraction of narrow fraction in vacuum residua

According to the structural parameters of molecular in the narrow cut of Daqing vacuum residue separated by the super critical fluid extraction,a series of molecular structures with various side chain distribution and side chain length were constructed on the premise of keeping the same average molecular structure parameters. Three-dimensional conformations of these molecules with minimum potential energies were obtained by using molecular mechanics and molecular dynamics. The side chain distribution factor and side chain length factor for quantitatively characterizing the molecular structures were obtained by correlating the molecular structures with their minimum potential energies. The two factors are linearly correlated with the minimum potential energies. Because the lower potential energy level results in the more stable structure and the most possible existence of molecular structure, the average molecular structures of side chain existing most possiblly in heavy oil are obtained.