Bitumen fractions responsible for stabilizing water in oil emulsions

• Author / Creator

  Yang,Fan

• During the extraction of crude oil or bitumen, stable water-in-oil emulsions are inevitably formed. The emulsified water contains chloride ions and other organic acidic compounds that cause severe corrosion problems to the downstream plant equipment, creating operational and safety issues and hence additional operation costs. The breakup of water-in-oil emulsions can be facilitated by the coalescence/flocculation between water droplets in the oil phase. In this thesis, a new methodology was developed to isolate interfacial asphaltenes from water in asphaltene solution emulsions to study the drainage kinetics, thickness and stability of water-in-oil thin liquid films stabilized by this fraction of asphaltenes in comparison with other heavy oil components such as asphaltenes-, heavy oil- (bitumen) and deasphalted heavy oil- (maltenes) diluted in toluene. The asphaltenes were found to be responsible for the formation of thicker films and slowing down the drainage kinetics due to their specific ability to self-assemble and to form 3D network in the film. The film forming behavior of asphaltenes was found to be determined from a small sub-fraction of interfacially active asphaltenes. The emulsion stabilization capacity and interfacial behavior of this sub-fraction of asphaltenes were compared to that of whole asphaltenes and remaining asphaltenes using bottle tests, thin liquid film technique, and Langmuir trough experiments. The results from these different techniques revealed stabilizing mechanisms of emulsions and interfacial films by this sub-fraction of asphaltenes. Chemical characterization including ESI-MS, H-NMR, 13C-NMR, FTIR and elemental analyses was used to construct chemical structures for this sub-fraction of asphaltenes and the remaining asphaltenes. These molecular structures of asphaltenes were used in Molecular Dynamics (MD) simulations in order to shed light on the functional groups and interactions that could be responsible for the aggregation and interfacial film formation of asphaltenes. Finally, the performance of an EO-PO block copolymer demulsifier on breaking up the asphaltene in toluene solution—water interface was analyzed by a suite of techniques including bottle test, micropipette coalescence test, viscoelasticity analysis, and AFM, SEM and Brewster Angle Microscope (BAM) imaging.

• Subjects / Keywords

  • Asphaltenes
  • Thin Liquid Film
  • Oil sands
  • Emulsification
  • Bitumen
  • Demulsification
  • Emulsions

• Graduation date

  Spring 2016

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R35T3G72Q

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.