Abstract Asphaltene precipitation is known as a challenging issue to fully upgrade heavy oils. In this study, asphaltene dispersion stability and sediment formation for a slurry phase hydrocracking reaction of vacuum residue was investigated with changes of temperatures (405–435 °C), LHSV (0.20–0.45 h r - 1 ), pressures (80–180 bar) and superficial gas velocities (0.4–2.2 cm/s) in a bench-scale continuous system. The characteristics of dispersion stability were examined with the solubility parameters at the flocculation point (UV titration), the structure of the asphaltenes (H-NMR), and sediment content in the liquid product (Hot filtration). As results, it was found that the dispersion stability of asphaltene was mainly dependent on the VR conversion. In particular, at about 50% of the VR transition, the solubility was found to be unstable and the amount of deposition increased dramatically. At the same time, microscopic observation directly confirmed asphaltene flocculation. However, when H2 partial pressure was increased, the hydrogenation reaction of asphaltene was promoted so that it could reduce sediment formation and improve both the asphaltene solubility and structure for the stable dispersion. On the other hand, increasing the superficial gas velocity did not give an effect on the asphaltene dispersion stability.

中文翻译：

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浆相加氢裂化反应中沥青质分散稳定性研究

摘要 沥青质沉淀被认为是重油全面提质的一个具有挑战性的问题。在这项研究中，研究了减压渣油浆相加氢裂化反应的沥青质分散稳定性和沉积物的形成，包括温度 (405–435 °C)、LHSV (0.20–0.45 hr - 1 )、压力 (80–180 bar) 的变化和表观气体速度 (0.4–2.2 cm/s) 在实验室规模的连续系统中。分散稳定性的特征通过絮凝点的溶解度参数（UV 滴定）、沥青质的结构（H-NMR）和液体产品中的沉积物含量（热过滤）来检验。结果发现，沥青质的分散稳定性主要取决于 VR 转化率。特别是在大约 50% 的 VR 过渡时，发现溶解度不稳定，沉积量急剧增加。同时，显微镜观察直接证实了沥青质絮凝。然而，当H2分压增加时，沥青质的加氢反应得到促进，从而减少沉积物的形成，改善沥青质的溶解度和结构，稳定分散。另一方面，增加表观气速对沥青质分散稳定性没有影响。促进沥青质的加氢反应，减少沉积物的形成，改善沥青质的溶解度和结构，稳定分散。另一方面，增加表观气速对沥青质分散稳定性没有影响。促进沥青质的加氢反应，减少沉积物的形成，改善沥青质的溶解度和结构，稳定分散。另一方面，增加表观气速对沥青质分散稳定性没有影响。