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Study of biodiesel-assisted ambient aqueous bitumen extraction (BA3BE) for hydrocarbon production from mineable oil sands

  • Author / Creator
    Zhu, Yeling
  • Surface mining followed by Clark’s hot water bitumen extraction (HWBE) process has been employed in the current mineable oil sands industry for massive bitumen production. This method is faced with numerous challenges such as high energy consumption, limited bitumen quality, production from poor-processing ores, and intractable sludge tailings settling.

    As a viable alternative to HWBE, a novel biodiesel-assisted ambient aqueous bitumen extraction (BA3BE) was developed in this study, which uses no caustic (NaOH) and features pretreating oil sands with a relatively small amount of biodiesel prior to extraction. By applying BA3BE, bitumen recovery from Athabasca oil sands was substantially improved from ~10% (benchmark) to 70–80% with 20 wt% (with respect to bitumen content) biodiesel addition at ambient temperature (25°C). Such temperature is much lower than the case of the current industry practice (45–50°C), indicating a remarkably reduced energy intensity. In addition, BA3BE allowed faster settling of oil sands extraction tailings and led to more compact sediment as compared to the case using caustic, suggesting a satisfactory tailings treatment.

    To further improve bitumen recovery and product quality, BA3BE was modified by incorporating the use of frother and demulsifier. Results indicated that the modified BA3BE achieved an increased bitumen recovery from 82.1% (unmodified BA3BE) to 86.4%, with a solvent dosage merely equivalent to half of the unmodified case. Further examination of bitumen product revealed that modified BA3BE reduced the entrained water impurities by ~1/3 and ~1/2 as compared to the unmodified case and the HWBE baseline, respectively.

    As part of the environmental impact evaluation, BA3BE was investigated in the release of toxic chemicals such as naphthenic acids, to tailings water. Results showed that BA3BE was able to reduce significantly the total intensity of released naphthenic acids by the range of 13.9–60.1%, depending on the type of ores. This suggests the evident effectiveness of BA3BE in reducing the release of major toxic chemicals to oil sands tailings water.

  • Subjects / Keywords
  • Graduation date
    Fall 2019
  • Type of Item
    Thesis
  • Degree
    Doctor of Philosophy
  • DOI
    https://doi.org/10.7939/r3-2233-t843
  • License
    Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.