The effect of froth on the dewatering of coals – An oscillatory rheology study

Zhang, Na; Chen, Xumeng; Nicholson, Timothy M.; Peng, Yongjun

doi:10.1016/j.fuel.2018.02.168

Cited by 20 publications

(12 citation statements)

References 31 publications

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“…Therefore, coal fines proper discharge can decrease the permeability loss within coal reservoirs [31,46]. The permeability loss rates of others are also higher 10 Geofluids than 80% except the 160-200 mesh at 2 MPa. The results demonstrate that the coupling relationship of crack width and fines size both affects the permeability loss degree.…”

Section: The Characteristic Of Permeability Lossmentioning

confidence: 96%

“…Further, coal fines occurrence can influence drainage continuity, causing dramatic borehole pressure fluctuations, and gas and water flow interruptions [8]. Coal fines blockage can also affect the spreading of pressure decreasing funnel and the gas production performance [9,10]. Controlling the stable output of coal fines is important for CBM wells production [11,12].…”

Section: Introductionmentioning

confidence: 99%

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An Experimental Study on Coal Fines Migration during Single Phase Water Flow

et al. 2020

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Coal fines migration and intrusion in coal fractures affect coalbed methane (CBM) wells performance by reducing reservoir permeability and production continuity. Physical simulations are conducted to investigate the permeability variation under different diameter coal fines intrusion at various flow velocities and confining pressures. The results show that the conductivity of fractures is dramatically reduced and hardly recover to its initial condition after coal fines intrusion. The permeability after coal fines intrusion (Pcfi) has no direct correlation with the increase of flooding velocity, while decreases with the increase of confining pressures. The fractures can be totally blocked by coal fines, while penetration also happened during the flooding process, causing permeability fluctuation. The permeability loss rates value for 80-120 mesh coal fines intrusion are generally <60% compared with the initial permeability, including the flow velocity of 2, 3, 4, 6, 8, and 10 mL/min with confining pressure of 6 MPa and the confining pressure of 2, 3, 4, 5, and 6 MPa with flow velocity of 3 mL/min. However, under 120+ mesh coal fines condition, the permeability loss rates are higher than 85% under most flow velocities and confining pressures. When coal fines become smaller, the permeability loss rates decrease to be lower than 45%, and part the coal fines are discharged with the water flow. Thus, coal fines proper dischargement can partly maintain the reservoir permeability during coalbed methane production. The results would be useful in understanding coal fines intrusion behaviors and its controlling strategies during CBM drainage.

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Section: The Characteristic Of Permeability Lossmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

An Experimental Study on Coal Fines Migration during Single Phase Water Flow

et al. 2020

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“…Besides, Zhang et al [98] have introduced a steady-state method for froth rheology measurement recently when investigating the effect of froth rheology on the dewatering of fine coals. Oscillatory rheology of froth was measured using a vane-in-cup system.…”

Section: Froth Rheology Measurementsmentioning

confidence: 99%

A Brief Review of Pulp and Froth Rheology in Mineral Flotation

Wang

2020

Journal of Chemistry

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In mineral flotation, rheological problems have limited the efficient upgrading of low-grade and complex ores. Since pulp and froth rheology are deemed to play different roles in influencing the separation performance, in this paper, a brief review on pulp and froth rheology in flotation is provided, with an objective of developing a basic understanding of rheology in flotation. The essential variables that affect the rheology of a flotation pulp and froth are discussed. The methods for measuring pulp and froth rheology are presented. The correlations of pulp and froth rheological properties to flotation performance are reviewed. Strategies that are currently used to mitigate the deleterious effects of problematic ores in flotation are also provided for flotation optimization. Research gaps are also proposed to highlight the need of further exploration of flotation rheology in future.

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“…After the flotation process, the concentrates must be settled and dehydrated. The strong particle interactions in the froth inhibit particle settling (Zhang et al, 2018a), and salt can accelerate the settling velocity of particles that detach from the froth (Zhang et al, 2019). The rheology of the mineral suspension during preparation is highly dependent on the properties of the mineral particles.…”

Section: Introductionmentioning

confidence: 99%

Effect of particle properties on rheology of low-concentration coal suspensions

Hou¹,

Ma²,

Fan³

et al. 2020

Physicochem. Probl. Miner. Process.

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In wet coal preparation, the products of some processes are transported as low-concentration suspensions. Their rheology is greatly affected by the properties of the coal particles that result from the formation and weathering during preparation. In this study, the properties of coal particles, including volumetric properties (i.e., solids content, granularity, and clay mineral fraction) and surface characteristics (i.e., dynamic potential, degree of coalification, and degree of surface oxidization), were studied to determine their effects on the apparent viscosity of low-concentration coal suspensions. With increasing solids content and smaller particle size in the suspension, the interactions between the coal particles became stronger due to the increased particle content, thus increasing the coal suspension's apparent viscosity. Adding clay minerals to the suspension gradually changed its composition and structure and increased its viscosity. The dynamic potential of the coal particles and inter-particle electrostatic repulsive forces were reduced with the addition of Ca 2+ ions, and the coal particles collided and aggregated, which increased the apparent viscosity of the suspension. For coal with a low degree of coalification or coal had been oxidized by a hydrogen peroxide solution, the suspension of the hydrophilic coal particles was associated with a lower apparent viscosity than that of highly hydrophobic solids, which tended to aggregate and form flocculent masses.

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The effect of froth on the dewatering of coals – An oscillatory rheology study

Cited by 20 publications

References 31 publications

An Experimental Study on Coal Fines Migration during Single Phase Water Flow

An Experimental Study on Coal Fines Migration during Single Phase Water Flow

A Brief Review of Pulp and Froth Rheology in Mineral Flotation

Effect of particle properties on rheology of low-concentration coal suspensions

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