Effect of Particle Size Distribution on Rheological Properties of Fly Ash Slurries at High Concentrations

Verma, A.; Singh, Sadhna; Seshadri, V.

doi:10.1615/interjfluidmechres.v33.i5.50

Cited by 13 publications

(8 citation statements)

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“…On the basis of literature review, five different surfactant concentrations i.e. 0.1%, 0.2%, 0.3%, 0.4%, and 0.5% of the total weight of the slurry were selected (Seshadri et al, 2005;Verma et al, 2008;Biswas et al, 2000;Li et al, 2002;Usui et al, 2001). An equal amount of a counter-ion same as that of the surfactant concentration was also added to the slurry to take care of the calcium and sodium ions naturally present in tap water (Kawaguchi et al, 1997;Feng-Chen et al, 2008;Munekata et al, 2006).…”

Section: Parametric Variations and Sample Preparationmentioning

confidence: 99%

“…The economic efficiency of this process depends on the power requirements for pumping, which in turn depend on the concentration, viscosity, and yield stress of concentrated slurries (Horsley, 1982). Certain additives enable the slurries to be pumped at much higher concentration of solids, thus reducing the water requirements, which is an important consideration in power plants to minimize the size of the ash pond area to accommodate the slurry (Seshadri et al, 2005;Verma et al, 2008;Biswas et al, 2000;Matras et al, 2007). Fly ash slurries consist largely of silica with varying amounts of other materials such as Al, Fe, and alkaline earth materials.…”

Section: Introductionmentioning

confidence: 99%

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The Effect of Drag-Reducing Additives on the Rheological Properties of Fly Ash-Water Suspensions at Varying Temperature Environment

Naik¹,

Mishra²,

Karanam³

2009

CCGP

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A B S T R A C TFly ash transportation and disposal is a major problem in India. Presently fly ash is being transported as lean slurry in pipe lines requiring about 80 to 85% of water which, in turn, consumes more energy input. The objective of the present study is to evaluate the rheological characteristics of fly ash slurry at varying temperatures with and without an additive to facilitate smooth flow in the pipelines. Six fly ash slurry samples were prepared from the fly ash obtained from a thermal power plant situated in the southern part of India. The main constituents of the slurry were fly ash, water, a cationic surfactant and a counter-ion. Detailed rheological properties were determined for the six slurries at shear rates varying from 25 to 500s 21 .Temperature was varied from 20uC to 40uC for all the shear rates investigated. The slurry exhibited Newtonian flow behaviour with zero yield stress. The slurry prepared in the above manner has a potential to be transported through pipelines with minimal energy consumption. The distinctive reduction of surface tension on colloidal disperse characteristics of the resulting slurry was observed in the presence of the surfactants. Zeta potential measurements also confirmed that the additive has the capability to keep the fly ash particles water borne during its transportation in pipelines.

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Section: Parametric Variations and Sample Preparationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Effect of Drag-Reducing Additives on the Rheological Properties of Fly Ash-Water Suspensions at Varying Temperature Environment

Naik¹,

Mishra²,

Karanam³

2009

CCGP

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“…The CGFB slurry was observed to exhibit non-Newtonian behavior [6]. A Bingham plastic model was found to be adequate for describing the slurry rheology at moderate shear rates [7,8]. The pilot plant loop test with a horizontal pipe was conducted during the CGFB pipeline transportation, in which the average loss of frictional resistance per unit length was observed as 3.80 kPa/m, while the average loss of local resistance was 4.11 kPa/m [9,10].…”

Section: Introductionmentioning

confidence: 99%

Pressure Study on Pipe Transportation Associated with Cemented Coal Gangue Fly-Ash Backfill Slurry

Yang

2019

Applied Sciences

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Cemented coal gangue-fly ash backfill (CGFB) slurry has commonly been used to control subsidence damage caused by underground coal mining. This paper discusses the characteristics of CGFB slurry fluidity in its pipe transportation. A general description about the components of the CGFB is provided involving the percentage of composition, particle size distribution (PSD) and rheological performance. The CGFB flow characteristics of the slurry pipeline were simulated in a straight pipe and 90° elbow pipe, respectively, combined with the pressure loss and conveying velocity distribution. With the help of the commercial computational fluid dynamic (CFD) code FLUENT, the modeling was conducted with various slurry feeding velocities. These results showed the local resistance loss in a bending pipe is significantly higher than the resistance in a straight pipe under the same conditions associated with CGFB transportation. The velocity distribution of the slurry solid particles in the slurry’s movement forward is more decentralized as the hydraulic inlet velocity increases. Based on these simulation data, a correlation was developed to predict the resistance loss of the CGFB slurry as a function of the hydraulic inlet velocity, pipe diameter and CGFB slurry rheological characteristics.

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“…Yang [14] has analyzed the pressure drop of highly concentrated coal ash slurries in loop pipe. Verma et al [15] have investigated the rheological behavior of highly concentrated fly ash slurries. Although the aforementioned studies on ash slurries have achieved important results, these results cannot directly apply to the CGFB slurries, since the ash slurries are essentially different from the CGFB slurries in terms of material composition.…”

Section: Introductionmentioning

confidence: 99%

Transportability and pressure drop of fresh cemented coal gangue-fly ash backfill (CGFB) slurry in pipe loop

Yang

Liu

2015

Powder Technology

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Effect of Particle Size Distribution on Rheological Properties of Fly Ash Slurries at High Concentrations

Cited by 13 publications

References 0 publications

The Effect of Drag-Reducing Additives on the Rheological Properties of Fly Ash-Water Suspensions at Varying Temperature Environment

The Effect of Drag-Reducing Additives on the Rheological Properties of Fly Ash-Water Suspensions at Varying Temperature Environment

Pressure Study on Pipe Transportation Associated with Cemented Coal Gangue Fly-Ash Backfill Slurry

Transportability and pressure drop of fresh cemented coal gangue-fly ash backfill (CGFB) slurry in pipe loop

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