Mixing of Diluted Bitumen and Conventional Crude Oil in Fresh and Marine Environments

• Author / Creator

  Farooqi, Hena Nusrat

• With public concern over potential impacts to water environments that could result from a spill of diluted bitumen during transportation, a study is being conducted to determine the mixing characteristics of diluted bitumen and conventional crude in fresh and salt water. The conventional crude (CC) and diluted bitumen (DB1) oils chosen for this study were selected because of their extensive transportation via pipelines, railways, and over water and, because of their relative differences in chemical and physical properties. The mixing behaviour between water and oil depends on the environment, oil composition and types of water and sediment. To study the relative effects of the different variables, mixing tests in a rotary agitator were conducted varying the oil (fresh conventional crude versus fresh diluted bitumen), water (salt versus fresh), temperature (ambient versus 30oC), sediment (sand versus diatomaceous earth), and mixing speed (38.7 versus 55.4 RPM, where both speeds were turbulent mixing regime).
  
  To sequentially examine the effects of all of variables, a total of 288 runs would be needed. However, factorial experimental design with five variables (oil, water, sediment, temperature and mixing speed) with two levels reduced the number of tests from 288 to 32, the minimum needed to obtain the key information about the effects of all variables (i.e. 5 factors at 2 levels each). This design allowed the study of 5 main effects, 10 two-factor interactions, 10 three-factor interactions, 5 four-factor interactions and 1 six-factor interaction. The data collected for the tests included emulsion formation, and water and oil mass balances. As well, floating oil was distilled to remove water. The boiling point (b.p.) >204°C fraction was separated into maltene and asphaltene fractions. Oil was isolated from the water and sediment phases by carbon disulfide and methylene chloride extraction. The maltenes and asphaltenes fractions and were then analyzed by high temperature simulated distillation, and elemental (CHNSO) analyses.
  The focus of this work comprised of two objectives; the first objective was to identify the significant variables in oil-water mixing and, the second objective was to identify the chemical reasons for the siginicant physical effects identified in the first study. It was seen that mixing behaviours in salt and fresh water were different, resulting in interesting patterns for oil loss and sediment interactions for both oils. From the initial variable screening study, it was found that salt water had the greatest impact on floating oil recovery with greater recovery of DB1 than CC in salt water; DB1 dispersed more in fresh water than CC; CC interacted more with sediment than DB1; and, thicker emulsions were formed when mixing with DB1. Analyses of the oil samples after mixing revealed the physical properties of each oil along with the presence of bioactivity and effects of interaction with sediment were causes for the changes that were observed during the mixing tests. From further analyses of the floating oil and sub fractions of the oil, it was found that the changes in the boiling point distributions were most significant when mixing with CC than DB1. There was also greater increase in the asphaltenes content after mixing with CC along with a greater increase in oxygen content in the asphaltenes fraction for CC.
  
  Further analyses of the metals content in the asphaltenes fraction, along with analysis of nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FTIR) data would provide insight to the source of oxygen.

• Subjects / Keywords

  • fresh water
  • significant effects
  • marine environment
  • mixing
  • Diluted bitumen
  • Conventional Crudie
  • oil spill
  • interactions

• Graduation date

  Fall 2018

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3HM53185

• License

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