Assessment of Amount of Emulsion Stabilizers in Oil Sands Bitumen
Date
2023-07
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Abstract
In current commercial oilsands bitumen extraction processes, ores of different quality are blended to utilize poorer quality ores and maintain a consistent processibility. The choice and proportion of ores in the blend is guided by the fines content of the ores. However, the processibility does not correlate consistently with the fines content, leading to poorer than predicted performance. It was hypothesized that the deviations in processibility were caused by differences in emulsion stability which could be attributed to different amounts of emulsion stabilizers in the bitumens from different ores. These stabilizers are believed to be concentrated in the asphaltenes, the least soluble fraction of the bitumen. To test the hypothesis, the amount of strong emulsifiers was assessed for asphaltenes from different mines in Alberta. Bitumen was extracted with cyclohexane using a multistage method equivalent to a counter current process with a solvent/ore ratio of 0.67 w/w. Asphaltenes were separated and the toluene insoluble components were removed. The asphaltenes were fractionated by solubility and interfacial adsorption methods. The strong stabilizer content was determined by comparing the stability of water-in-oil emulsions prepared from the different fractions dissolved in a solution of heptane and toluene. Finally, the stability of water-in-oil emulsions prepared from bitumen in the same solution was measured to determine if the there was a correlation between the strong stabilizer content and water-in-bitumen emulsion stability. No correlation was found and therefore the hypothesis was disproven and variations in strong stabilizer content are not likely to impact ore processibility. The extraction data collected in this study also allowed testing the claim that bitumen recovery in non-aqueous extraction (NAE) is unaffected by ore quality. Bitumen recovery and product quality were measured for each ore. It was observed that bitumen recovery correlated negatively with the clay content of the ore. This loss of recovery was attributed to bitumen adsorption on clays, where higher clay content led to greater mass adsorption and lower recovery. The product quality was found to be insensitive to the ore quality.
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Keywords
Asphaltene, Water-in-Oil Emulsion, Emulsion Stabilizer, Non-Aqueous Extraction, Recovery, Oil sands
Citation
Tamayo Duran, L. C. (2023). Assessment of amount of emulsion stabilizers in oil sands bitumen (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.