Segregation in water fluidized beds of sand particles

Đuriš, Mihal; Garić‐Grulović, Radmila; Arsenijević, Zorana; Jaćimovski, Darko; Grbavčić, Željko

doi:10.1016/j.powtec.2012.10.004

Cited by 11 publications

(4 citation statements)

References 18 publications

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“…(2). Well-known examples of spherical particles are the conventional equation proposed by Schiller and Naumann (1933), the equation proposed by Fair et al (1954), often applied in water treatment, and the equation proposed by Brown and Lawler (2003), which covers a wide range of terminal Reynolds numbers. Prediction models for non-spherical particles are also based on the appearance of Eq.…”

Section: Terminal Settling and Drag Coefficient -Models From The Literaturementioning

confidence: 99%

“…Schiller and Naumann (1933) * 13.0 % 7.0 % 18.4 % 11.3 % 0.91 0.93 Fair et al (1954) 16.7 % 10.1 % 20.2 % 13.1 % 0.89 0.96 Clift and Gauvin (1971) 12.4 % 6.2 % 17.4 % 9.0 % 0.91 0.96 Clift et al (1978) 12.4 % 6.3 % 17.9 % 9.1 % 0.91 0.96 Turton and Levenspiel (1986) 12.7 % 6.4 % 17.9 % 9.1 % 0.91 0.96 Flemmer and Banks (1986) 13.0 % 6.8 % 18.4 % 9.8 % 0.91 0.97 Khan and Richardson (1987) 12.0 % 6.2 % 17. Haider and Levenspiel (1989) 14.0 % 6.5 % 20.0 % 8.8 % 0.91 0.97 Ganser (1993) 17.6 % 8.6 % 24.5 % 11.1 % 0.89 0.96 Chien (1994) 17.3 % 9.9 % 22.0 % 13.1 % 0.87 0.96 * Results were rejected when boundary conditions (known limits of applicability) were violated.…”

Section: Natural and Processed Highly Non-spherical Polydisperse Particlesmentioning

confidence: 99%

“…The settling behaviour of natural grains in drinking water treatment processes is of great importance (Camp, 1946;Cheremisinoff, 2002;Edzwald, 2011;Howe et al, 2012;Crittenden et al, 2012). Examples include pellet softening in fluidised bed reactors (Graveland et al, 1983), sedimentation, flotation and flocculation, filtration processes (Amburgey, 2005;Tomkins et al, 2005), backwashing of filter media, and washing columns in which fine material and impurities are separated from seeding material (Cleasby et al, 1977;Soyer and Akgiray, 2009).…”

Section: Introductionmentioning

confidence: 99%

“…In these processes, the particle size mostly varies between 0.3-2 mm, and the particle density varies between 1.2-4 kg L −1 . The societal call for a circular economy (Filho and Sümer, 2015;Marques et al, 2015) has put pressure on water utilities to change their policies (Ray and Jain, 2011) -also in terms of making treatment processes more sustainable. The reuse of waste materials is an example of this transition from a linear to a circular approach.…”

Section: Introductionmentioning

confidence: 99%

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Can terminal settling velocity and drag of natural particles in water ever be predicted accurately?

Kramer

Moel²,

Raaghav

et al. 2021

Drink. Water Eng. Sci.

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Abstract. Natural particles are frequently applied in drinking water treatment processes in fixed bed reactors, fluidised bed reactors, and sedimentation processes to clarify water and to concentrate solids. When particles settle, it has been found that, in terms of hydraulics, natural particles behave differently when compared to perfectly round spheres. To estimate the terminal settling velocity of single solid particles in a liquid system, a comprehensive collection of equations is available. For perfectly round spheres, the settling velocity can be calculated quite accurately. However, for naturally polydisperse non-spherical particles, experimentally measured settling velocities of individual particles show considerable spread from the calculated average values. This work aims to analyse and explain the different causes of this spread. To this end, terminal settling experiments were conducted in a quiescent fluid with particles varying in density, size, and shape. For the settling experiments, opaque and transparent spherical polydisperse and monodisperse glass beads were selected. In this study, we also examined drinking-water-related particles, like calcite pellets and crushed calcite seeding material grains, which are both applied in drinking water softening. Polydisperse calcite pellets were sieved and separated to acquire more uniformly dispersed samples. In addition, a wide variety of grains with different densities, sizes, and shapes were investigated for their terminal settling velocity and behaviour. The derived drag coefficient was compared with well-known models such as the one of Brown and Lawler (2003). A sensitivity analysis showed that the spread is caused, to a lesser extent, by variations in fluid properties, measurement errors, and wall effects. Natural variations in specific particle density, path trajectory instabilities, and distinctive multi-particle settling behaviour caused a slightly larger degree of the spread. In contrast, a greater spread is caused by variations in particle size, shape, and orientation. In terms of robust process designs and adequate process optimisation for fluidisation and sedimentation of natural granules, it is therefore crucial to take into consideration the influence of the natural variations in the settling velocity when using predictive models of round spheres.

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Section: Terminal Settling and Drag Coefficient -Models From The Literaturementioning

confidence: 99%

Section: Natural and Processed Highly Non-spherical Polydisperse Particlesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Can terminal settling velocity and drag of natural particles in water ever be predicted accurately?

Kramer

Moel²,

Raaghav

et al. 2021

Drink. Water Eng. Sci.

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Adsorption on Activated Carbon

2023

Drinking Water Treatment 2

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Bed Expansion and Particle Classification in Liquid Fluidized Beds with Structured Internals

et al. 2015

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The inclusion of a structured packing as internal in a liquid-solid fluidized bed allows expansion of the liquid velocity operation range before elutriation, promoting the liquid solid contact and mixing. The bed expansion of liquid-solid fluidized beds provided with structured packing as internals is examined, for solids denser than the liquid phase and within a wide range of operating conditions. A correlation to estimate the bed expansion in liquid-solid fluidized beds using structured packing as internals is developed. In addition, the feasibility of employing structured packing as internals for favoring classification of different density particles is demonstrated by analyzing the mass elutriated from the column at different liquid velocities for single particles or binary mixtures.

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Segregation in water fluidized beds of sand particles

Cited by 11 publications

References 18 publications

Can terminal settling velocity and drag of natural particles in water ever be predicted accurately?

Can terminal settling velocity and drag of natural particles in water ever be predicted accurately?

Adsorption on Activated Carbon

Bed Expansion and Particle Classification in Liquid Fluidized Beds with Structured Internals

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