渣油的分子组成模拟研究

针对渣油中分子的结构组成，提出了一种基于结构导向集总的构建渣油分子的方法，选定65种单核分子和12种多核分子作为种子分子，以不同碳数的侧链进行具体地划分，构建了共计3 749个虚拟分子来代表渣油。采用15种基本的结构向量组成的分子矩阵来描述每个分子的组成，可用于表示分子反应过程以及各分子物性的计算。以渣油中各分子特征分布为基础确定各分子摩尔含量的计算式，构建各物性计算值相对误差的目标函数，利用模拟退火算法计算渣油中各分子的相对含量。选取三种渣油试样进行分子建模研究，模拟计算结果表明，渣油各物性的计算值和实验测定值基本吻合，每种渣油芳香分的相对分子质量也呈现明显的γ分布。这3 749种分子可以基本反映渣油的整体性质，用分子特征分布的方法来计算渣油分子的相对含量是可行的。

SIMULATION STUDY OF MOLECULAR COMPOSITION OF RESIDUE

Based on the molecular type homologous series matrix, a structure oriented lumping (SOL) method was established to simulate molecular composition of residue, where 65 single cores and 12 multi-cores assumed structure were chosen as the seed molecules which were divided by carbon number of the side chain, resulting in 3 749 kinds of virtual molecules to represent the residue molecular compositions. Each molecule was composed of 15 kinds of basic structure vectors to represent the reaction process of molecules and to calculate the individual properties. With the structural attribute distributions of the residue, the mole fractions of each molecule can be confirmed, and the bulk properties were derived from the calculated mole fractions and the individual properties. Therefore, the mole fractions were determined based on the parameters of the attribute distributions by simulation annealing algorithm. As the results of 3 kinds of residual samples show that the calculated values of bulk properties of residue are in accordance with the measured ones, the distribution of the molecular weight reveals obvious gamma distribution for relative molecular mass of each residue aromatics. It is feasible to represent the residue with the 3 749 kinds virtual molecules, and the method based on the structural attribute distributions can well be used to calculate the mole fractions.