Catalytic hydropyrolysis of El-Lajjun and Julia Creek shale oils using flow-through and sealed autoclaves

Jameel S. Aljariri Alhesan, Marc Marshall, W. Roy Jackson, Peter J. Cassidy, Alan L. Chaffee

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Abstract

High-sulfur shale oils from two marine oil shales, El-Lajjun (Jordan) and Julia Creek (Australia) were subjected to hydropyrolysis using NiMo catalysts deposited on Al-SBA-15 with Si/Al ratios ranging from 10 to 75, i.e. with decreasing acidity, both in a flow-through system at 0.1 MPa H2 pressure and in sealed autoclaves at varying H2 pressure (1–6 MPa (cold, i.e., at room temperature)). For autoclave pyrolysis of El-Lajjun shale oil catalysed by NiMo-Al-SBA-15 (Si:Al = 10:1), sulfur content of oil decreased with H2 pressure, catalyst:oil ratio and temperature, pyrolysis time having little effect. Coking decreased with increasing H2 pressure, but increased with increasing temperature and catalyst:oil ratio. Time had little effect on coking. The conditions finally adopted were 400 °C, 6 MPa (cold) H2 pressure, 30 min pyrolysis time and (0.1:1.0) catalyst:oil ratio. Lower Si/Al ratios (≤50) all gave the same hydrodesulphurization (HDS) activity, but coking declined with decreasing Si/Al ratio, so that the optimum ratio was 10. The Julia Creek shale oil also showed good HDS, but was more susceptible to coking at high Si/Al ratio. The oil obtained in catalysed pyrolysis contained almost no thiophenes or benzothiophenes and had more high-boiling point material than oil from non-catalysed pyrolysis. The catalyst was successfully regenerated after use and was also effective in HDS of both raw oil shales. For the flow-through experiments, no significant hydrodesulphurization (HDS) was observed for either shale oil, but some hydrodenitrogenation (HDN) occurred for the Julia Creek shale oils.

Original languageEnglish
Article number104682
Number of pages11
JournalJournal of Analytical and Applied Pyrolysis
Volume143
DOIs
Publication statusPublished - Oct 2019

Keywords

  • Al-SBA-15
  • High-sulfur marine shale oils
  • Hydrodesulphurization
  • Nickel-molybdenum catalyst
  • Pyrolysis conditions

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