超声波处理对渣油加氢反应前后沥青质结构组成的影响

利用超声波处理渣油，考察超声波对渣油加氢反应前、后沥青质缔合状况和结构的影响。结果表明：超声波处理改变了沥青质的结构状态，但没有改变沥青质的元素组成；超声波处理可降低沥青质的单元薄片缔合数，使部分环烷烃发生开环反应而增大其支化度，沥青质的平均相对分子质量和结构参数中的RT，RA，RN，CA，σ，Dy均减小，同时沥青质中不同类型氢原子的含量也发生变化；加氢过程中，沥青质主要发生桥键断裂、脱烷基侧链和缩合反应，使结构参数中的fA，CAP，n，RT，RA，CA，Dy，BI和平均相对分子质量M增大，而σ，H/C，nsw，X/n减小；超声波处理改善了沥青质的结构和反应性能，再经加氢反应时强化了上述变化趋势，加氢后的沥青质结构更为复杂，甚至出现缔合数为7~11的沥青质分子。

INFLUENCE OF ULTRASONIC PRETREATMENT ON ASPHALTENE STRUCTURE BEFORE AND AFTER HYDROTREATING

The effect of ultrasonic pre-treatment, followed by hydrotreating, on the status of association and structure of asphaltene was examined. The results indicate that ultrasonic treatment can change the asphaltene structure, but not the content of chemical elements. The structure changes caused by ultrasonic pre-treatment include the reduction of association number and increase of the branching degree through opening the naphthenic ring of asphaltene. Ultrasonic treatment reduces the molecular weight and the structure parameters of asphaltene, such as RT, RA, RN, CA and Dy. The distribution and types of hydrogen atoms are also changed. The molecular weight and parameters of fA, CAP, n, RT, RA, CA, Dy, BI of hydrotreated asphaltene increases because the occurrence of bridge bond rupture, dealkylation and condensation during the residue hydrotreating, while σ, H/C, nsw and X/n are decreased. These changes in structure and reactivity of asphaltene are helpful to residue hydrotreament. The functions of ultrasonic pretreatment are reinforced by hydrotreating. The structure of hydrotreated asphaltene was more complicated and the associating number of molecule even reaches 7 to 11.