2 research outputs found

    Biodiesel-Assisted Ambient Aqueous Bitumen Extraction (BA<sup>3</sup>BE) from Athabasca Oil Sands

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    The water-based extraction process has been almost exclusively used in the current industry for Athabasca oil sands extraction to produce bitumen and heavy oil. However, the current method is facing various challenges, primarily including high energy intensity, poor processability with poor-quality ores, large consumption of fresh water, and concerns on considerable volume of tailings. Although the technology of using nonaqueous solvent as extraction medium has numerous advantages, problems such as solvent loss to tailings and high capital/operating costs are difficult to address. A biodiesel-assisted ambient aqueous bitumen extraction (BA<sup>3</sup>BE) process has been herein proposed as an alternative to water-based and solvent-based extraction processes. The results showed a significant improvement in both froth quality and bitumen recovery (increased from ∼10% to ∼80% with biodiesel addition) for processing poor-quality ores at ambient temperature (25 °C), which is much lower than the temperatures used in the current industrial practice (40–55 °C). The aqueous tailings generated in the BA<sup>3</sup>BE process were found to feature faster settling and enhanced densification, which is favorable for recovering processing water and improving land reclamation. Furthermore, the innovative BA<sup>3</sup>BE extraction process requires similar facilities and procedures as the current industrial processes, which can be considered as an advantage for commercialization

    Nanostructures in Water-in-CO<sub>2</sub> Microemulsions Stabilized by Double-Chain Fluorocarbon Solubilizers

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    High-pressure small-angle neutron scattering (HP-SANS) studies were conducted to investigate nanostructures and interfacial properties of water-in-supercritical CO<sub>2</sub> (W/CO<sub>2</sub>) microemulsions with double-fluorocarbon-tail anionic surfactants, having different fluorocarbon chain lengths and linking groups (glutarate or succinate). At constant pressure and temperature, the microemulsion aqueous cores were found to swell with an increase in water-to-surfactant ratio, <i>W</i><sub>0</sub>, until their solubilizing capacities were reached. Surfactants with fluorocarbon chain lengths of <i>n</i> = 4, 6, and 8 formed spherical reversed micelles in supercritical CO<sub>2</sub> even at <i>W</i><sub>0</sub> over the solubilizing powers as determined by phase behavior studies, suggesting formation of Winsor-IV W/CO<sub>2</sub> microemulsions and then Winsor-II W/CO<sub>2</sub> microemulsions. On the other hand, a short C2 chain fluorocarbon surfactant analogue displayed a transition from Winsor-IV microemulsions to lamellar liquid crystals at <i>W</i><sub>0</sub> = 25. Critical packing parameters and aggregation numbers were calculated by using area per headgroup, shell thickness, the core/shell radii determined from SANS data analysis: these parameters were used to help understand differences in aggregation behavior and solubilizing power in CO<sub>2</sub>. Increasing the microemulsion water loading led the critical packing parameter to decrease to ∼1.3 and the aggregation number to increase to >90. Although these parameters were comparable between glutarate and succinate surfactants with the same fluorocarbon chain, decreasing the fluorocarbon chain length <i>n</i> reduced the critical packing parameter. At the same time, reducing chain length to 2 reduced negative interfacial curvature, favoring planar structures, as demonstrated by generation of lamellar liquid crystal phases
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