Effect of the annulus aeration on annulus leakage and particle circulation in a three-phase spout-fluid bed with a draft tube

Erbil, Ayşe Çeçen

doi:10.1016/j.powtec.2005.11.006

Cited by 9 publications

(7 citation statements)

References 12 publications

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“…Due to the scarcity of spout-fluid bed data permitting the calculation of shear stresses and velocity gradients, the analysis is restricted to the data of Grbavcic et al () and Çeçen Erbıl ( , ). The spout-fluid bed with the 1.94 mm glass particles has an Re t of 469; therefore, the flow of this system is assumed to result in transition flow conditions whereas the spout-fluid bed with the 3 mm glass particles has an Re t of 933 indicating turbulent flow ( , ).…”

Section: Resultsmentioning

confidence: 99%

“…All raw data necessary for the calculation of the energy dissipation parameters, including the draft tube voidage and the dynamic pressure gradient inside the draft tube, are those of Grbavcic et al () and Çeçen Erbıl ( , ). In both cases, the equipment used is a spout-fluid bed of semi-circular geometry.…”

Section: Methodsmentioning

confidence: 99%

“…The variables measured include the total flow rate into the spout-fluid bed alongside with the spouting and annulus inlet flow rates and the pressure profiles inside the draft tube. In the experiments conducted by Çeçen Erbıl ( , ), the spouting inlet flow and the annulus liquid inlet flow were introduced into the spouted bed by two independent lines connected to pumps and flow meters. Air was introduced into the annulus through the same flow distributor that was used for the annulus liquid.…”

Section: Methodsmentioning

confidence: 99%

“…The voidage and the particle velocity in the draft tube were calculated by the variational method of Grbavcic et al (). Table lists the voidage, particle velocity, and superficial flow rate ( U d ) inside the draft tube together with the experimental conditions used by Çeçen Erbıl ( , ).…”

Section: Methodsmentioning

confidence: 99%

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Assessment of the Energy Dissipation Parameters Inside the Draft Tube of a Liquid Spout-Fluid Bed

Erbil

Turan

2005

Environ. Sci. Technol.

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Spouted beds are fluid-particle contactors in which the fluid is introduced centrally through a nozzle instead of a distributor plate, resulting in a regular particle circulation pattern. To assess the suitability of such sytems to environmental engineering applications such as filter backwashing and biofilm systems, a priori knowledge of the energy dissipation parameters is essential. A new model is developed for evaluating the energy dissipation parameters inside the draft tube of spout-fluid beds. The shear stress, velocity gradient, and turbulence fluctuation parameters in the draft tube of a liquid spout-fluid bed are calculated with the help of an energy equation for flows carrying suspensions and the experimentally determined pressure losses inside the draft tube and compared with results for particulately fluidized beds. A spout-fluid bed with a draft tube provides higher shear stress inside the draft tube than a fluidized bed. The mean velocity gradient in the draft tube is comparable to and higher than in a fluidized bed and increases with solids fraction. The turbulence dissipation coefficient decreases very slightlywith increasing solids fraction for both systems. Consequently, according to the model calculations, a spout-fluid bed with a draft tube can be an alternative to the classical fluidized bed filter backwashing system.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Assessment of the Energy Dissipation Parameters Inside the Draft Tube of a Liquid Spout-Fluid Bed

Erbil

Turan

2005

Environ. Sci. Technol.

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“…The fluid (in this case air and wastewater) enters the vessel through a spouting nozzle at the base, and flows through the bed of solid particles (Fan et al [2]). The resulting hydrodynamic pattern shows three distinct regions: an upward jet (spout), a downward movingpacked bed (annulus) and a characteristic fountain above the bed surface (Çeçen-Erbil [3], Cui and Grace [4]). Furthermore, in bioreactors, the shear forces exerted on the surface of the solids by the recirculation between the spout and annulus provides a good control of the growth of biofilm thickness (Livingston and Chase [5]).…”

Section: Introductionmentioning

confidence: 99%

Biodegradation of phenol in a draft-tube spouted bed bioreactor with biomass attached to hydrogel particles

Safont

Vitas

Peñas

2009

WIT Transactions on Ecology and the Environment

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The performance of a draft-tube spouted bed bioreactor (DT-SBB) packed with hydrogel particles for biomass immobilization has been used to treat a phenolic wastewater in continuous mode. The biomass support particles were made of a cyclodextrin-based polymer and then seeded with an acclimated mixed culture. Due to the low density of such particles and also the bioreactor design, the pumping energy required to maintain a moving bed of the resulting bioparticles was very low and a recirculation flow was not necessary. The inlet phenol concentration and the phenol inlet loading rate were the operating variables studied. Phenol removal efficiency was used to monitor the process. The DT-SBB showed a high removal capacity (up to 2.8 kg-phenol/m 3 d) with a high efficiency (>99%). The removal capacity of the DT-SBB was found to be limited by the availability of dissolved oxygen in periods with high phenol elimination rate. The removal efficiency decreased significantly for higher loading rates (>3.1 kg/m 3 d) because of phenol inhibition. The evolution of the distribution of microbial populations was also investigated. A predominance of gram-negative bacteria (especially the genera Pseudomonas and Acinetobacter) was observed during the periods of maximum degradation.

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A new empirical equation for minimum spouting/spout‐fluidization velocity in draft tube spout‐fluid beds at elevated temperature

Guo

Xie

et al. 2015

Can J Chem Eng

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Draft tube spout‐fluid beds have been widely used in drying, coating, and granulation processes. In these processes, the spout‐fluid reactor is always operated at gas temperatures that exceed ambient conditions. Therefore, one objective of draft tube spout‐fluid bed research is to determine the critical factors that affect the minimum spouting velocity (Ums) and the minimum spout‐fluidization velocity (Umsf) at high temperatures. In this study, four types of particles were used to study the resulting pressure drops. Ums and Umsf were used in a conical draft tube spout‐fluid bed at temperatures of 293–500 K. In addition, a series of operating conditions and geometric configurations were investigated to systematically study the factors that affect Ums and Umsf. Overall, Ums and Umsf increased as the static bed height, entrainment zone height, draft tube diameter, and particle diameter increased. In contrast, Ums decreased as the superficial fluidizing gas velocity and spout nozzle diameter increased. In addition, Umsf increased as the superficial fluidizing gas velocity, spout nozzle diameter, and temperature increased. Furthermore, as the fluidizing gas flow increased, the minimum spouting velocity shifted from increasing to decreasing as the temperature gradually increased. Two general correlations between the Ums and Umsf values and the above factors were proposed. In addition, the influences of operating conditions and geometrical parameters on the minimum spouting velocity should be considered in the design and use of draft tube spout‐fluid beds.

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Effect of the annulus aeration on annulus leakage and particle circulation in a three-phase spout-fluid bed with a draft tube

Cited by 9 publications

References 12 publications

Assessment of the Energy Dissipation Parameters Inside the Draft Tube of a Liquid Spout-Fluid Bed

Assessment of the Energy Dissipation Parameters Inside the Draft Tube of a Liquid Spout-Fluid Bed

Biodegradation of phenol in a draft-tube spouted bed bioreactor with biomass attached to hydrogel particles

A new empirical equation for minimum spouting/spout‐fluidization velocity in draft tube spout‐fluid beds at elevated temperature

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