Effect of Graft Density of Partially Hydrophobic Copolymers on the Treatment of Oil Sands Mature Fine Tailings

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dc.contributor.advisorTrifkovic, Milana
dc.contributor.authorKalyanaraman, Gayathri
dc.contributor.committeememberLu, Qingye Gemma
dc.contributor.committeememberAchari, Gopal
dc.contributor.committeememberTrifkovic, Milana
dc.contributor.committeememberNassar, Nashaat
dc.date2022-02
dc.date.accessioned2021-12-16T14:56:56Z
dc.date.available2021-12-16T14:56:56Z
dc.date.issued2021-12-07
dc.description.abstractAlberta is well renowned for its oil sands mining that has led to enormous deposits of waste called tailings (alkaline slurry of residual bitumen, clay, and water). The presence of clays and fine silts in the tailings successively reduce their ability to settle naturally and dewater under the effects of gravity. The continuous accumulation of the tailings and the inability to treat them pose a risk to its surroundings. To resolve these issues, industries utilize several techniques, among which flocculation methodology is commonly employed to enhance the dewatering performance, capture the suspended solids, and improve the strength of the tailings using polymers (flocculants). The flocculation effectiveness depends on the polymer design with respect to the tailings system it is acting on, and this comes from understanding the microstructure of the polymer-flocculated sediment. Traditionally there are two broad groups of polymers: hydrophilic (water-liking) and hydrophobic (water-hating) for MFT (Mature fine tailings) flocculation. Researchers have shifted the focus to partially hydrophobic flocculants due to the long-term consolidation issues with conventional hydrophilic flocculants. This study employs partially hydrophobic copolymers with three different graft densities (30%, 40%, 50%). A combination of mechanical (Rheology, Dean-stark) and imaging (Laser Scanning Confocal Microscopy (LSCM)) experiments were conducted to understand and correlate the microstructure of polymer with that of the resulting MFT aggregates. Rheological experiments were performed to assess the strength of the treated MFT sediment. The LSCM was employed to image the microstructure of the polymer dispersion and the flocculated MFT aggregates. The obtained MFT images were further quantified in volume fraction and fractal dimension to evaluate the amount of inter-floc water (present between the flocs). Similarly, Dean-Stark experiments were performed to evaluate the amount of intra-floc water (enclosed within the individual flocs). It was shown that as the graft density of the polymers increased, the “initial” flocculation performance considerably improved. In contrast, there was no significant change in the “long-term" rheological signature among the three samples. The information on the inter-floc and intra-floc water obtained from LSCM and Dean-Stark studies have contributed to a better understanding of the spatial distribution of water within the flocculated sediment and their response to the polymer behaviour at varying graft densities. The effect of increasing the polymer graft density has led to a decrease in the dewatering rate with an increase in the amount of intra-floc water in the MFT sediment post flocculation. This approach clarifies that the flocculant's design, as understood from the spatial distribution of the water, plays a significant part in influencing the water release and water-retention ability of the flocs.en_US
dc.identifier.citationKalyanaraman, G. (2021). Effect of Graft Density of Partially Hydrophobic Copolymers on the Treatment of Oil Sands Mature Fine Tailings (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.en_US
dc.identifier.doihttp://dx.doi.org/10.11575/PRISM/39420
dc.identifier.urihttp://hdl.handle.net/1880/114174
dc.language.isoengen_US
dc.publisher.facultySchulich School of Engineeringen_US
dc.publisher.institutionUniversity of Calgaryen
dc.rightsUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.en_US
dc.subjectOil Sands Mature Fine Tailingsen_US
dc.subjectClayen_US
dc.subjectBitumenen_US
dc.subjectFlocculationen_US
dc.subjectConfocalen_US
dc.subjectRheologyen_US
dc.subject.classificationGeochemistryen_US
dc.subject.classificationEngineering--Environmentalen_US
dc.subject.classificationEngineering--Petroleumen_US
dc.titleEffect of Graft Density of Partially Hydrophobic Copolymers on the Treatment of Oil Sands Mature Fine Tailingsen_US
dc.typemaster thesisen_US
thesis.degree.disciplineEngineering – Chemical & Petroleumen_US
thesis.degree.grantorUniversity of Calgaryen_US
thesis.degree.nameMaster of Science (MSc)en_US
ucalgary.item.requestcopytrueen_US
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