Population balance modelling of dense clay slurries flocculation

Pougatch, Konstantin; Delfel, Sean; Hosseini, Majid; Moyls, Benny; Sadighian, Ardalan; Revington, Adrian

doi:10.1016/j.ces.2020.116260

Cited by 5 publications

(5 citation statements)

References 21 publications

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“…Some early work by Hogg, later extended by Swerin et al, proposed a model for collision efficiency based on surface coverage of the particles. [33,34] Equation (10) describes how bridging flocculation affects capture efficiency, with a maximum efficiency when the effective surface coverage, θ, is 50%.…”

Section: Model Developmentmentioning

confidence: 99%

“…Population balances have been developed to model the flocculation of different particle types, including calcite, [ 7 ] kaolinite and quartz, [ 8 ] latex microparticles, [ 9 ] fine tailings slurries, [ 10 ] and oil sands tailings. [ 11 ] Modelling particle size changes during flocculation involves two main events: (1) aggregation, in which particles collide, stick together, and form larger flocs, and (2) fragmentation, during which shear forces break larger aggregates into smaller particles.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…[6] Despite these challenges, population balances can help understand the flocculation process and have been incorporated into computational fluid dynamics (CFD) models to better predict larger-scale operations. [6,10,12,13] In this article, we used a population balance model to describe the aggregation of oil sands mature fine tailings (MFT) using the cationic flocculant poly(vinyl benzyl trimethylammonium chloride) (PVBTMAC). This model rests on the shoulders of the previous model by Vajihinejad and Soares, [11] but adds a new fundamental feature: experimental adsorption data to describe how MFT aggregates respond to changes in the flocculant dosage.…”

Section: Introductionmentioning

confidence: 99%

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Using polymer adsorption data and a population balance model to estimate how polymer dosage affects the flocculation of oil sands tailings

Dixon

Soares

2023

Can J Chem Eng

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Population balance models can describe how particles aggregate and fragment during the flocculation of mineral tailings. We used a new method to estimate some of the parameters in a population balance model describing the flocculation of oil sands mature fine tailings with poly(vinyl benzyl trimethylammonium chloride). Differently from previous population balance models, the polymer adsorption data onto the particles suspended in the tailings were used to estimate a fundamental parameter relating polymer dosage to the mean diameter of the aggregates formed during flocculation. The model could predict the flocculation behaviour of three polymer samples with different molecular weights. This model is another step toward a quantitative understanding of how polymer properties affect the flocculation of mineral tailings.

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Section: Model Developmentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Using polymer adsorption data and a population balance model to estimate how polymer dosage affects the flocculation of oil sands tailings

Dixon

Soares

2023

Can J Chem Eng

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“…Each of these technologies requires the fluid tailings to be pretreated to promote fine-particle aggregation, enhance solid-liquid separation and promote dewatering. Presently, in-pipe mixing of fluid fine tailings with a dilute polymer solution, known as inline flocculation, is the method of choice (Wells et al, 2011;Wang et al, 2014, Pougatch et al, 2021. The success of the inline flocculation depends primarily on (Pougatch at al., 2021) efficient mixing of the polymer solution into the fluid tailings; polymer adsorption onto the fine particles; and the balance of floc (aggregate) formation and growth with floc breakdown due to shear exposure.…”

Section: Introductionmentioning

confidence: 99%

Use of Pipeline Pressure Gradients to Monitor Inline Polymer Flocculation of Oil Sand Fine Tailings

Kumar,

Moyls,

Sadighian

et al. 2023

The 20th International Conference on Transport and Sedimentation of Solid Particles. 50th Anniversary

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In Canada’s oil sands industry, the processing and storage of fluid fine tailings is important because it directly impacts land usage and reclamation, water and thermal energy requirements as well as environmental stewardship and mine sustainability. A key technology used for this purpose is inline flocculation, wherein existing inventories of fluid fine tailings are withdrawn from tailings storage facilities and mixed with polymer flocculants. These flocculated tailings can be then sent through additional process stages (e.g. evaporation, centrifugation, filtration) to promote dewatering and improved geotechnical characteristics of the resulting deposits. The polymer type, dosage and inline mixing conditions primarily dictate the efficacy of the inline flocculation process. Presently, numerous measurements are taken to establish flocculation performance. Some of these require samples to be collected and analyzed, meaning that such measurements cannot be used for real-time process control. Others, such as online FBRM (focus beam reflectance measurement), can be used for real-time process control but are often challenging and expensive to deploy in a commercial operation. The present study represents a preliminary assessment of the use of pressure measurements to monitor flocculation performance using a pilot-scale inline flocculation rig. Tests were conducted at different flow rates and polymer injection rates/concentrations. The test rig was fitted with 4 differential pressure sensors positioned at different axial locations. The pressure gradients measured just downstream of the inline mixer were primarily dictated by the production, and subsequent break-up, of the shear-sensitive floc structures and thus were highly sensitive to changes in polymer dosage at any given fluid tailings feed rate. A relationship among conventional performance metrics (e.g. floc size from FBRM) and maximum pressure gradient measured downstream of the mixer was observed, i.e. the same optimal polymer dosage was indicated by conventional measures and peak pressure gradient.

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Polymeric flocculation of oil sands tailings: Unveiling rheological indicators and dynamics of bitumen release

Sasar,

Johnston,

Santagata

2024

Can J Chem Eng

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Polymeric flocculation is widely used to accelerate the dewatering and consolidation of oil sands fluid fine tailings (FFTs). Optimizing flocculation requires a fundamental understanding of the changes to the internal structure of the material with polymer addition. Key challenges include sensitivity of flocculation to polymer dose, mixing conditions, and composition of individual FFTs. Moreover, despite the environmental implications, little is known of the effects of flocculation on the mobility of the residual organics present in the tailings. In this paper, advanced rheological tests are used to probe the formation and development of the polymer–clay structure during flocculation in near‐real time. This is achieved through a novel setup for controlled delivery of the polymer directly into the measuring cell of a rheometer. This enables continuous monitoring of the rheological parameters during the flocculation process and yields consistent and reproducible samples. An optical monitoring system is used to relate rheological measurements to water release and to changes in the surface accumulation of the residual bitumen. The water‐release polymer dose is found to be associated with a distinct rheological response highlighting the potential use of rheometry for polymer dosing/mixing optimization in real time and on a continuous basis in thickeners and inline flocculation systems.

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Population balance modelling of dense clay slurries flocculation

Cited by 5 publications

References 21 publications

Using polymer adsorption data and a population balance model to estimate how polymer dosage affects the flocculation of oil sands tailings

Using polymer adsorption data and a population balance model to estimate how polymer dosage affects the flocculation of oil sands tailings

Use of Pipeline Pressure Gradients to Monitor Inline Polymer Flocculation of Oil Sand Fine Tailings

Polymeric flocculation of oil sands tailings: Unveiling rheological indicators and dynamics of bitumen release

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