Catalytic cracking reaction of heavy oil in the presence of cerium oxide nanoparticles in supercritical water

Mehdi Dejhosseini, Tsutomu Aida, Masaru Watanabe, Seiichi Takami, Daisuke Hojo, Nobuaki Aoki, Toshihiko Arita, Atsushi Kishita, Tadafumi Adschiri

Research output: Contribution to journalArticle

56 Citations (Scopus)

Abstract

Catalytic cracking of Canadian oil sand bitumen in supercritical water was performed to clarify the effect of CeO2 nanoparticles. The cracking was performed at 723 K to promote a redox reaction between the water, bitumen, and catalyst for the production of hydrogen and oxygen. As the catalyst, CeO2 with two different morphologies was employed because the redox reaction of CeO2 with water and organics is expected and its activity can be controlled by its structure. In this study, two roles of water were considered as well. Water is attractive as a high potential medium with low dielectric constant and density at near the critical point (374 C, 22.1 MPa) that allows formation of highly crystalline smaller metal oxides particles. However, the chemical effects of water are investigated with heavy oil catalytic cracking. Transmission electron microscopy images indicated that CeO 2 nanoparticles with cubic and octahedral shape were synthesized using a plug-flow reactor under hydrothermal conditions. The particles sizes were 8 and 50 nm for cubic and octahedral CeO2, respectively. At 773 K, it was found that the oxygen storage capacity (OSC) of the cerium oxide nanoparticles with cubic {100} facets was nearly 3.4 times higher than that of the cerium oxide nanoparticles with octahedral {111} facets. Heavy oil fractions of bitumen were cracked in a batch-type reactor at 723 K in order to produce as much light oil as possible, and the effect of the catalyst loading and reaction conditions on the conversion rate and coke formation were investigated. As a result, it was demonstrated that it is possible to obtain a high conversion rate by increasing the exposed surface area and reducing the particle size of the catalyst. The highest conversion was obtained in the presence of 20 mg loading of cubic CeO2 nanoparticles (8 nm) with reaction time of 1 h.

Original languageEnglish
Pages (from-to)4624-4631
Number of pages8
JournalEnergy and Fuels
Volume27
Issue number8
DOIs
Publication statusPublished - 2013 Aug 15

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Energy Engineering and Power Technology
  • Fuel Technology

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