重油特征分子尺寸的精确计算方法

THE ACCURATE CALCULATING METHOD FOR MOLECULAR DIMENSIONS OF HEAVY OIL CHARACTER MOLECULES

采用量子化学方法计算得到重油特征分子的几何结构,提出了用量子化学方法计算重油特征分子的最小横截面直径和描述分子尺寸的方法。预测了代表性的重油特征分子的最小横截面直径。结果表明,理论计算与实验测定的分子尺寸一致。大庆渣油窄第一馏分、第二馏分和残渣馏分的特征分子的最小横截面直径分别为1.8703、3.0080和3.4929nm,因此这3种渣油分子均不能直接进入孔径较小的沸石分子筛,而只能在其表面发生一级催化反应。研究结果可为筛选和设计合成分子筛提供有用的理论依据。

Quantum chemistry method was used to calculate the geometry structure of heavy oil character molecule. The method to calculate the minimum cross-sectional diameter of heavy oil character molecule and to show the molecular dimension was brought forward, which was used to predict the minimum cross-sectional diameter of some typical heavy oil character molecules. It is shown that the theory calculated result was consistent with experimental date. The minimum crosssectional diameters of Daqing first cut （DQ-fcut） , middle cut （DQ-mcut） and end cut （DQ-endcut） were 1. 8703, 3. 0080 and 3. 4929 nm, respectively, meaning that these kinds of heavy oil molecules are too big to enter the sieve pore of zeolites, so they could be only cracked on the surface of zeolite. These research results can offer some useful theory basis to the selection and synthesis of zeolites.