大港常压渣油临氮与临氢热反应过程中胶体稳定性变化研究

对比了大港常压渣油临氮和临氢热反应过程中的胶体稳定性变化。结果表明，随着反应时间的延长，在热反应生焦诱导期内，渣油样品的胶体稳定性迅速下降；开始生焦后，胶体稳定性缓慢下降。从组分组成和组分性质角度,对大港常压渣油样品在热反应过程中胶体稳定性变化原因进行了分析。结果表明，随着反应时间的延长，沥青质含量先上升、后下降，在生焦诱导期结束时达到最大值，与体系胶体稳定性的变化特征相一致。随着热反应的进行，饱和分和轻芳烃组分的含量在上升，重芳烃、轻胶质、中胶质、重胶质含量下降，临氮热反应过程中轻胶质、中胶质、重胶质含量的下降更为显著。对渣油样品各组分的数均相对分子质量和平均偶极矩进行了研究。结果表明，随着热反应的进行，轻、中、重胶质组分的数均相对分子质量和平均偶极矩呈下降趋势，而沥青质的数均相对分子质量和偶极矩先增大后减小，从而使沥青质和胶质的分子性质差别先增加后减小，与体系胶体稳定性的变化趋势一致；同时沥青质的偶极矩变化表明,强极性的沥青质优先聚集生焦、临氢热反应过程中，氢与催化剂的作用有助于抑制沥青质分子量增大和极性增强，从而有助于抑制生焦。

Colloidal stability variation of Dagang atmosphere residue during thermal reaction under nitrogen or hydrogen

Colloidal stability variation of Dagang atmosphere residue (DG-AR) during thermal reaction under nitrogen or hydrogen was comparatively investigated. It was found that the colloidal stability of DG-AR samples decreases sharply along with the thermal reaction until coke is formed, and then the deterioration of the colloid stability is slowed down. At the aspect of the composition and characteristics of residue fractions, it was found that with the proceeding of the thermal reaction, the content of asphaltenes reaches its maximum at the end of coke induction period; the content of saturates and light aromatics fraction increases, while the content of heavy aromatics, light resins, middle resins, or heavy resins decreases. This trend is more prominent for the thermal reaction under nitrogen. The mean dipole moments and mean relative molecular weight of the residue fractions were measured, which suggested that as the thermal reaction is going on, the mean relative molecular weight and the mean dipole moments of maltene fractions decrease, while those of asphaltenes have their maximum values. This variation is consistent to that for the colloidal stability during the thermal reaction. The dipole moment variation of asphaltenes showed that asphaltenes having more polarity tend to be associated and transformed into coke. Furthermore, the catalyst and hydrogen is able to restrain asphaltenes from condensation and coke formation.