Microbubble Enhanced Bitumen Separation from Tailing Slurries with High Solid Contents

Abstract

Removing bitumen from oil-sands tailings reduces greenhouse gas emission during waste disposal. However, it is technically challenging to efficiently recover bitumen residual in tailing slurries with high solid contents, due to the tiny fraction of bitumen and complicated composition in the tailings. This work focuses on microbubble-enhanced bitumen recovery in a flow of artificial tailings that consisted of 50 wt% solids, 0.2 wt% bitumen and 49.8 wt% process water. Using a laboratory\textendash scale transport pipeline loop, we show that several operation conditions had a positive impact on the efficiency of bitumen recovery, including bubble formation from intensified cavitation, the addition of gas integrated with cavitation, or increasing the temperature up to 52 C. The efficiency of bitumen recovery was even higher from the addition of CO_{2} bubbles compared to air bubbles. Under optimal conditions, more than 61 % bitumen was recovered from an extremely initial fraction of 0.2 wt% with the generation of microbubbles. This work provides guideline in finding an effective combination of operational conditions for bitumen separation from hydrotransported real tailings containing high solid content. The same approach may be also applicable for cleaning of oil contaminated slurries.

Computational fluid dynamics investigation of bitumen residues in oil sands tailings transport in an industrial horizontal pipe

“…Recently Motamed Dashliborun et al [22] reported experimental work that the optimal bitumen recovery of 50 % was achieved from the oil sand tailings of 6.68 wt % sands and 0.2 wt % bitumen with microbubble injection in a hydrotransport pipeline [22]. Furthermore, a higher bitumen recovery of 70 % from highly concentrated oil sand tailings of 50 wt % sands was obtained in the following work conducted by Zhou et al [23]. Numerous investigations have studied the mechanism of flotation behavior in the presence of microbubbles [25][26][27].…”

“…To recover residual bitumen before discharging to the tailing ponds, several innovative experimental studies have been conducted to enhance bitumen recovery with microbubble injection in a lab-scale pipeline [21][22][23][24]. Though a vast number of theoretical and experimental studies on liquid-solid flow can be found in the literature, very few studies related to the gas-liquid-solid flow were available, and uncertainties exist in modeling this flow.…”