Water-Assisted Solvent Extraction of Bitumen from Oil Sands

Abstract

Water-assisted solvent extraction processes (WASEPs) were developed by introducing a water layer between the oil sands and solvent to extract bitumen from oil sands. The extraction condition was well investigated using the naphtha as the extraction solvent. Considering the extraction cost, the advised extraction processes for industrial application were conducted under stirring at temperature of 50−60 °C for 30 min using a ratio of oil sands to naphtha to water in 1:1:0.5 (wt/wt/wt). At such conditions, bitumen recovery of about 72−74% was obtained on processing a weathered ore. In the case of some types of oil sands such as the weathered ore, surfactant needs to be added in the aqueous phase to eliminate the solids aggregation suspended in the oil−water interface. The function of the water layer introduced in the WASEPs is to reduce the fines content in the extracted bitumen solution and make it easy to separate the bitumen solution from the solids. In the examination of the solvent recovery, it was found that there was 7% of the solvent still remaining in the solids. The loss of the solvent greatly depends upon the surface wettability of the solids. Studies on the effect of various solvents on bitumen recovery indicated that using toluene as the extraction solvent gave the highest bitumen recovery of about 95%. However, considering the extraction cost and environmental problems, the water-assisted naphtha extraction processes were advised and might find its application in the oil sands processing industry, although some issues need to be resolved in the future work.

Sorption equilibrium and kinetics for cyclohexane, toluene, and water on Athabasca oil sands solids

“…Solvent extraction of bitumen as an alternative technology to the current warm water extraction process offers high bitumen recovery (> 90 %) from a range of ores . Several promising solvents have been identified including aromatics, n ‐alkanes, and cycloalkanes .…”

“…[1] Solvent extraction of bitumen as an alternative technology to the current warm water extraction process offers high bitumen recovery (> 90 %) from a range of ores. [3][4][5][6][7][8][9][10][11][12][13][14][15] Several promising solvents have been identified including aromatics, n-alkanes, and cycloalkanes. [11,12,15] The extraction gangue, a mixture of sands and fine solids after solvent extraction, is almost dry and can be stacked, allowing for fast reclamation of the mining site.…”

Vacuum drying of cyclohexane from solvent‐extracted oil sands gangue

“…One alternative technology is extraction of bitumen by dissolution in light hydrocarbon solvents instead of flotation in hot water . With recoveries of 80–95 %, this method is less sensitive to variation in the grade of the ore and the surface properties of the solids . Low‐boiling solvents can be recovered by evaporation from the waste stream, or gangue .…”

“…[4] With recoveries of 80-95 %, this method is less sensitive to variation in the grade of the ore and the surface properties of the solids. [5][6][7][8][9][10][11][12] Low-boiling solvents can be recovered by evaporation from the waste stream, or gangue. [6][7][8]11,[13][14][15][16][17][18][19][20][21][22][23][24][25] Low losses of solvent in the gangue are essential for an economical process that is environmentally acceptable, [26] and achieving such results on a commercial scale for oil sands is a major technological challenge.…”

Application of microbial enhanced oil recovery technology in water‐based bitumen extraction from weathered oil sands

“…11 The effect of weathering on oil sands processability has been reported recently. 9,[12][13][14][15][16] By studying a laboratory weathered ore and a naturally weathered ore, a mechanism on the deteriorated processability of oil sands due to weathering was proposed by Masliyah and coworkers. 11,13 It was suggested that the formation water loss because of weathering led to a close contact of bitumen with the solids surface and hence resulted in the adsorption of organic matter.…”