加氢反应时间对塔河沥青质结构组成的影响

在高压釜反应器中考察了反应时间对加氢后沥青质结构组成的影响。结果表明，加氢后沥青质缔合体的平均相对分子质量、H/C原子比、结构单元数以及芳香环系缩合度参数HAU/CA均减小，芳碳分率升高，沥青质在加氢反应过程中发生了明显的烷基侧链和环烷环脱除反应及缩合反应，使次生沥青质的缩合度增加。加氢后沥青质中Hα和Hγ所占氢原子的比例减小，Hβ和HA的比例增加，沥青质的加氢过程既有正碳离子反应，又有自由基反应。次生沥青质单元薄片的总环数和平均相对分子质量增大，单元薄片间可以发生脱氢缩合反应。随反应时间的延长，沥青质结构参数的变化幅度逐渐减小，沥青质的加氢转化反应时间以控制在2小时左右为宜，过长的反应时间无益于反应的进一步进行。

Influence of Hydrotreating Time on Hydrotreated Asphaltene Structure

The influence of reaction time on structure parameters of hydrotreated asphaltene was studied in autoclave. The results showed that the molecular weight, H/C, numbers of unit, HAU/CA of hydrotreated asphaltene decreased, but the aromatic-carbon ratio increased. The condensation degree of secondary asphaltene increased by dealkylation and dehydrogenative condensation reactions in asphaltene hydrotreating. There are both carbonium ion mechanism and free radical mechanism in asphaltene hydrotreating because the rations of Hα and Hγ decreased in hydrotreated asphaltene, but Hβ and HA increased. The total number of rings and molecule weight of secondary asphaltene unit increased. It is proved that the dehydrogenative condensation reactions occurred among asphaltene units in hydrotreating. The change ranges of structure parameters decreased gradually with the increase of reaction time. The suitable reaction time of asphaltene hydrotreating is 2 hours and the over-long reaction time is not benefit to asphaltene hydrotreating.