Using Polymer Reaction Engineering Principles to Help the Environment: The Case of the Canadian Oil Sands Tailings

Soares, João B. P.; Motta, Fernanda Lopes

doi:10.21577/0103-5053.20180197

Cited by 5 publications

(4 citation statements)

References 28 publications

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“…10−12 Currently, flocculation with anionic polyacrylamide polymers represents one of the most effective approaches to accelerate the dewatering of FFTs for final integration into reclaimed landscape 13 and a common first step used in combination with other tailings dewatering technologies. 14 Although modern recovery methods are efficient, 15 some of the bitumen present in the ore is trapped during extraction and is lost into the tailings stream. Residual or fugitive bitumen in FFTs is generally between 1 and 3%, but this value can be higher.…”

Section: Introductionmentioning

confidence: 99%

“…The dominant constituent of fluid fine tailings is water followed by the slow settling clay particles that have contributed to the enormous buildup of stored fluid fine tailings, estimated at 1.36 × 10 9 m 3 in tailings ponds . The significant accumulation of current and legacy fine tailings has become one of the major operational and environmental challenges facing the oil sands industry. − Currently, flocculation with anionic polyacrylamide polymers represents one of the most effective approaches to accelerate the dewatering of FFTs for final integration into reclaimed landscape and a common first step used in combination with other tailings dewatering technologies …”

Section: Introductionmentioning

confidence: 99%

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Characterization and Dynamics of Residual Organics in Oil Sands Fluid Fine Tailings

2022

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Fluid fine tailings (FFTs) generated by the surface mining of oil sand ore bodies are high-water-content, clay-rich materials that contain unrecovered bitumen and additional residual organics, including solvents used during bitumen extraction. Despite a large accumulated inventory of these tailings and despite the environmental implications and challenges that the presence of organics poses, little is known about the differences in the residual organics generated by different bitumen extraction processes and about the effects of polymeric flocculation on mineral–organic interactions. This study investigated residual organics in two compositionally different FFTs both before and after flocculation with a commercially available polyacrylamide polymer. Thermogravimetric (TG) analysis, Fourier transform infrared (FTIR) spectroscopy, and evolved gas analysis (EGA-TG-FTIR) were used to characterize the makeup of total organics, free bitumen, and mineral-associated organics. These observations highlighted distinct differences between the FFTs. Relative to the sample receiving waste only from the bitumen extraction process (FFT-1), the FFT sample that received waste from both the extraction and the froth treatment processes (FFT-2) exhibited a higher residual organic content and a larger fraction of lower-molecular-mass organic substances and showed a proportionally smaller release of free bitumen as a result of the washing process, evidence of a higher fraction of mineral-associated organics. Moreover, TG and FTIR analyses showed that the free bitumen released from both FFTs contained a higher fraction of lighter organics and was characterized by a more ordered molecular structure compared to the remaining organics. Finally, the study also found that the bitumen release characteristics of FFT-1 were fundamentally different from those of FFT-2. Bitumen release continued to be observed from both FFTs after polymeric flocculation.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Characterization and Dynamics of Residual Organics in Oil Sands Fluid Fine Tailings

2022

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“…Due to the urgency of the problem, considerable effort has gone into developing methods for accelerating the dewatering and consolidation of MFT. , Physical/mechanical, chemical, biological, and natural methods have been examined as a means of accelerating the settling and dewatering of MFT. Chemical technologies have focused on using coagulants and/or flocculants to densify and remove the water from the MFT, and a wide variety of materials have been examined for this purpose. − The flocculants that appear to be the most widely used by the oil sands industry are anionic polyacrylamides (A-PAMs) . However, the supernatants generated with these flocculants are quite turbid, which is mainly due to the negative charges on the clays and other ultrafines.…”

Section: Introductionmentioning

confidence: 99%

Nonthermoresponsive and Thermoresponsive Cationic Starch for the Flocculation of Oil Sands Mature Fine Tailings

Zheng

Taylor

2021

Energy Fuels

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The mature fine tailings (MFT) in the massive tailing ponds created during bitumen extraction from oil sands must be dewatered before the land and water can be reclaimed. Here, we report the first studies employing cationic starch as a flocculant of MFT. Two types of cationic starch were examined: nonthermoresponsive cationic starches containing 2-hydroxypropyltrimethylammonium groups with molar substitutions of 0.02 (Cat0.02-St) and 0.2 (Cat0.2-St) and a thermoresponsive cationic starch containing both 2hydroxypropyltrimethylammonium groups and hydroxybutyl groups with molar substitutions of 0.02 and 2.0, respectively (Cat0.02-HB2.0-St). These biopolymers were evaluated for their ability to flocculate 2 and 10 wt % MFT, in tap water and oil sands process water (OSPW), in terms of initial settling rate (ISR), supernatant turbidity (ST), sediment solids content (SSC), and water recovery (WR). All of the modified starches were capable of flocculating 2 wt % MFT in OSPW and tap water, though the ISR values were higher when using OSPW. Cat0.02-HB2.0-St exhibited higher ISR values than Cat0.02-St, was particularly effective when employed at a temperature (50 °C) above its lower critical solution temperature (LCST), in contrast to Cat0.02-St did not exhibit overdosing over the dose range examined, and had a very broad flocculation window. Cat0.02-St was unable to flocculate 10 wt % MFT at the highest dose tested (10 000 ppm), while in OSPW, 10 000 ppm of Cat0.2-St was a good flocculant with an ISR of 17.1 m/h and an ST of 19 nephelometric turbidity units (NTU). With 10 wt % MFT in OSPW at 50 °C, 10 000 ppm of Cat0.02-HB2.0-St was very effective with an ISR of 34.9 m/h, an ST of 47 NTU, and an SSC of 64 wt % obtained after centrifugation of the flocculation sediment. At 50 °C, 10 000 ppm of Cat0.02-HB2.0-St did not perform as well as 1000 ppm of Magnafloc 1011, a commercial anionic polyacrylamide, in terms of ISR and WR but provided a cleaner supernatant and a higher final solids content after centrifugation of the flocculation sediment.

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“…Thus, a mathematical model would help to monitor the flocculation process. Recent studies have tested a series of multifunctional copolymers, terpolymers and graft copolymers to flocculate oil sand tailings (Soares and Motta 2019;Botha et al 2017;Bazoubandi and Soares 2020).…”

Section: Introductionmentioning

confidence: 99%

Reduction of asphaltenes adsorbed on kaolinite by polymers based on cardanol

Maravilha

Middea

Spinelli

et al. 2020

Braz. J. Chem. Eng.

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Oilsands are suspended fine solids in bitumen in which asphaltenes become adsorbed on the surfaces of these particles, reducing the quality of the oil and hence generating higher costs for the oil industry. Since some polymers containing specific functional groups are able to interact with asphaltenes, it can be expected that these kinds of polymers are able to reduce the amount of asphaltene adsorbed. In this work, the performance of three (co)polymers, with different molar ratios of cardanol and styrene was evaluated in the adsorption process of a model system (pentane insoluble asphaltenes-C5I in kaolinite) monitored by ultraviolet-visible spectrometry. Kaolinite and asphaltene were characterized by scanning electron microscopy with energy dispersive X-ray spectroscopy and the wettability of these samples was measured with a goniometer, before and after the adsorption process. The increase in polymer concentration (from 0.025 to 0.2%w/v) reduced the amount of adsorbed asphaltenes on kaolinite. Polycardanol homopolymer presented the best performance, indicating the important role of the hydroxyl group and pendent hydrocarbon chain on the adsorption of asphaltenes on kaolinite. The results evidence the potential of polycardanol, obtained from a renewable source, in the extraction process of bitumen from oil sand.

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Using Polymer Reaction Engineering Principles to Help the Environment: The Case of the Canadian Oil Sands Tailings

Cited by 5 publications

References 28 publications

Characterization and Dynamics of Residual Organics in Oil Sands Fluid Fine Tailings

Characterization and Dynamics of Residual Organics in Oil Sands Fluid Fine Tailings

Nonthermoresponsive and Thermoresponsive Cationic Starch for the Flocculation of Oil Sands Mature Fine Tailings

Reduction of asphaltenes adsorbed on kaolinite by polymers based on cardanol

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