Mechanisms of Aggregation and Separation of Water and Solids from Bitumen Froth using Cluster Size Distribution

• Author / Creator

  Arora, Nitin

• The large-scale corrosion and equipment damage caused by water and solids respectively in bitumen froth necessitate their removal using various methods. This study is aimed at understanding how water and solids aggregate (water-water, water-solid and solid-solid) in bitumen froth and what the dominant aggregation/ settling mechanism is during gravity separation (coalescence, flocculation and sweep flocculation). Initially, we compared two mixing/ settling tank designs: one with side sampling ports and another with top sampling ports, to ensure that our sampling method is robust and gives a representative sample. The side sampling design gave more meaningful results for the two test emulsions. Bitumen froth contains a large amount of water and solids. Hence, a robust image analysis algorithm was developed to quantify the type of clusters (water-water or water-solid), the cluster size and the number of drops and/or particles in the cluster. Using this clustering algorithm, it was found that water drops flocculate with each other and also sweep flocculate the nearby solids. A low water concentration in the product layer also ensured low solids concentration. Solid-solid aggregates were rarely observed. The change in water drop size distribution over 60 min of settling indicated some evidence of coalescence. Coalescence was also visually observed for free water which could happen over hours or even days. Hence, flocculation and sweep flocculation are both important settling mechanisms for the demulsifier used in this study. Changing the mixing conditions (demulsifier injection concentration and mixing energy) did not change the dominant settling mechanism. Good mixing promotes aggregate growth, resulting in faster settling and lower final water and solids concentrations, both of which are crucial for industrial operations.

• Subjects / Keywords

  • Bitumen froth
  • Aggregation
  • Solids
  • Coalescence
  • Image analysis
  • Sweep Flocculation
  • Settling mechanism
  • Water
  • Flocculation
  • Mixing energy

• Graduation date

  Fall 2016

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3057CX97

• 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.