Carbon dioxide assisted paraffinic froth treatment

• Author / Creator

  Wang, Xue

• In the paraffinic froth treatment (PFT), a large amount of paraffinic solvent is used to
  produce very clean bitumen products which can be transported directly to market without
  an upgrading step. However, the high solvent usage demands a large capacity in tailings
  solvent recovery unit. To solve this problem, CO 2 has been proposed as a processing aid in
  PFT to assist asphaltene precipitation so that less paraffinic solvents are needed.
  In this study, the onset point of asphaltene precipitation was determined by a gravimetric
  method and confirmed by the optical microscopy method at different solvent-to-bitumen
  (S/B) ratios. Then, the asphaltene precipitation with the injection of CO 2 was performed at
  different pressure and temperature conditions. Afterwards, the experiments were extended
  to test the effect of water addition, and finally to directly test the treatment of bitumen froth
  with paraffinic solvent addition and CO 2 injection. The bitumen and asphaltene were
  characterized by the total acid number (TAN) measurements.
  All the asphaltene precipitation experiments were also conducted with N 2 as control, in
  which the asphaltene precipitation was under different pressure and temperature conditions.
  The impacts of water and solids on asphaltene precipitation were also investigated.
  iii
  To examine the optimal condition at the industrial operating range, the CO 2 -assisted PFT
  experiments were conducted at low pressure range (0.1-1.7MPa) and low temperatures
  (21℃, 90℃). At 90℃, with the injection of 1.7 MPa CO 2 and addition of 52 wt% of n-
  heptane, the asphaltene yield reached 15.3%, which means 80.6% of total asphaltene was
  precipitated. To reach the same asphaltene yield without CO 2 , the n-heptane concentration
  needed to be 75.5 wt%. Therefore, by using 1.7 MPa CO 2 in PFT, the n-heptane
  concentration could be reduced by 24.9 percentage point, or 32.4 wt %.

• Subjects / Keywords

  • carbon dixoide
  • paraffnic froth treatment

• Graduation date

  Fall 2020

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-v5e1-5d51

• 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.