Recycling the CoMo/Al2O3catalyst for effectively hydro-upgrading shale oil with high sulfur content and viscosity

Suleiman Sabo Bello, Chao Wang, Mengjuan Zhang, Zhennan Han, Lei Shi, Kangjun Wang, Ziyi Zhong, Fabing Su*, Guangwen Xu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Hydrotreatment is an effective upgrading technology for removing contaminants and saturating double bonds. Still, few studies have reported the hydro-upgrading of shale oil, with unusually high sulfur (13200 ppm) content, using the CoMo/Al2O3catalyst. Here we report an extensive study on the upgrading of shale oil by hydrotreatment in a stirred batch autoclave reactor (500 ml) for sulfur removal and viscosity reduction. From a preliminary optimization of the reaction factors, the best-operating conditions were 400 °C, an initial H2-pressure of 5 MPa, and an agitation rate of 800 rpm, a catalyst-to-oil ratio of 0.1, and a reaction time of 1 h. We could achieve a sulfur removal efficiency of 87.1% and 88.2% viscosity reduction under the optimal conditions. After that, the spent CoMo/Al2O3was repeatedly used for subsequent upgrading tests without any form of pre-treatment. The results showed an increase in the sulfur removal efficiency with an increase in the number of catalyst runs. Ultimately, 99.5-99.9% sulfur removal from the shale oil was achieved by recycling the spent material. Both the fresh and the spent CoMo/Al2O3were characterized and analyzed to ascertain their transformation levels by XRD, TEM, TG, XPS, TPD and N2adsorption analysis. The increasing HDS efficiency is attributed to the continuing rise in the sulfidation degree of the catalyst in the sulfur-rich shale oil. The light fraction component in the liquid products (IBP-180 °C) was 30-37 vol% higher than in the fresh shale oil. The product oil can meet the sulfur content requirement of the national standard marine fuel (GB17411-2015/XG1-2018) of China.

Original languageEnglish
Pages (from-to)37287-37298
Number of pages12
JournalRSC Advances
Issue number61
StatePublished - 8 Oct 2020


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