The dynamics of large particles in a four-compartment interconnected fluidized bed

1999 ◽  
Vol 101 (3) ◽  
pp. 229-239 ◽  
Author(s):  
F.F. Snieders ◽  
A.C. Hoffmann ◽  
D. Cheesman ◽  
J.G. Yates ◽  
M. Stein ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Large Particles

Bubble eruption diameter in a fluidized bed of large particles at elevated temperatures

1981 ◽  
Vol 36 (7) ◽  
pp. 1259-1260 ◽  
Author(s):  
Norkun Sitthiphong ◽  
Alan H. George ◽  
Dwight Bushnell
Keyword(s):  
Fluidized Bed ◽  
Elevated Temperatures ◽  
Large Particles

The Pressure Drop at Critical Fluidization of Large Particles in Vibrated Fluidization Bed

2012 ◽  
Vol 550-553 ◽  
pp. 2763-2766
Author(s):  
Xue Jun Zhu ◽  
Jun Deng
Keyword(s):  
Pressure Drop ◽  
Fluidized Bed ◽  
Large Particle ◽  
Particle Diameter ◽  
Future Design ◽  
Vibration Strength ◽  
Bed Height ◽  
Large Particles ◽  
Vibrated Fluidized Bed ◽  
Critical Fluidization

The pressure drop at critical fluidization for two-dimensional vibrated fluidized bed(240 mm×80 mm) was studied, with large particle glass beads of average diameters dp of 1.8mm, 2.5mm and 3.2mm.The effect of the vibration strength, the static bed height and the particle diameter on the pressure drop was analyzed. The results of the study show that the pressure drop decreases with the increase of the vibration strength. It plays an even more prominent part with decreases of the static bed height and the particle diameter. The empirical correlation equations to predict the pressure drop was established, and the results of the prediction was compared with the experimental data, the error is in range of ±10%. The results can provide references for future design and research on the vibrated fluidized bed.

MATHEMATICAL MODELLING OF SIMULTANEOUS HEAT AND MASS TRANSFER IN FLUIDIZED BED DRYING OF LARGE PARTICLES

1999 ◽  
Vol 23 (1B) ◽  
pp. 129-145 ◽  
Author(s):  
E. Hajidavaloo ◽  
F. Hamdullahpur
Keyword(s):  
Mass Transfer ◽  
Partial Differential Equations ◽  
Differential Equations ◽  
Heat And Mass Transfer ◽  
Fluidized Bed ◽  
Solid Phase ◽  
Variable Mass ◽  
Partial Differential ◽  
Large Particles ◽  
Fluidized Bed Drying

A mathematical model for simulation of simultaneous unsteady heat and mass transfer in fluidized-bed drying of large particles is proposed. A set of coupled non-linear partial differential equations is employed to accurately model the process without using adjustable parameters. A three phase model representing a bubble (dilute) phase, interstitial gas phase and a solid phase is used to describe the thermal and hydrodynamic characteristics of the bed. The bubble and temperature distributions inside the solid phase is applied. The flow field is divided by an orthogonal grid to a finite number of control volumes to simulate the variation of the properties for the three phases in longitudinal direction. The Crank-Nicholson implicit numerical method is applied to solve the set of coupled nonlinear partial differential equations with variable mass and thermal diffusivity for a spherical-shape particle. A pilot-scaled fluidized bed dryer was built to test the results of proposed model with those obtained by experiments using wheat particles as a bed charge. A good agreement between the numerical and experimental results is observed.

scholarly journals Application of image processing on struvite recovery from swine wastewater by using the fluidized bed

2017 ◽  
Vol 77 (1) ◽  
pp. 159-166 ◽  
Author(s):  
Zhi-Long Ye ◽  
Yujun Deng ◽  
Xin Ye ◽  
Yaoyin Lou ◽  
Shaohua Chen
Keyword(s):  
Image Processing ◽  
Particle Size ◽  
Fluidized Bed ◽  
Swine Wastewater ◽  
Granulation Process ◽  
Large Particles ◽  
Different Types ◽  
The Common ◽  
Mass Increase ◽  
Coating Growth

Abstract Fluidized granulation is one of the common methods used in wastewater treatment and resource recovery with harvesting millimeter-scale large particles. Presently, effective methods are lacking to measure the fluidized granules ranging from micro- to millimeter scales, with the consequence of ineffectively controlling and optimizing the granulation process. In this work, recovering struvite (MgNH4PO4·6H2O) from swine wastewater by using a fluidized bed was taken as an example. Image processing was applied to analyze the properties of different types of struvite granules, including morphology, particle size distribution, number density and mass concentration. Four stages of the struvite crystal evolution were therefore defined: aggregation, aggregate compaction, cluster-agglomerating and coating growth. These stages could occur simultaneously or sequentially. Up-flow rates of 30–80 mm/s in the fluidized bed sustained 600–876 g/L granular solids. Results revealed that the coating-growth granules were formed with compact aggregates or cluster-agglomerating granules as the nuclei. The growth rates for the different types of particles, including population growth, mass increase and particle size enlargement, were determined. In final, a schematic illustration for struvite granulation process is also presented.

Study of Defluidization Region of Large Particles in Fluidized Bed Using the Gaussian Spectral Pressure Distribution

2015 ◽  
Vol 1104 ◽  
pp. 69-74
Author(s):  
Flavia Tramontin Silveira ◽  
Frederic Conrad Janzen ◽  
Maria Regina Parise
Keyword(s):  
Pressure Distribution ◽  
Fluidized Bed ◽  
Pressure Fluctuations ◽  
Fixed Bed ◽  
Environment Temperature ◽  
Large Particles ◽  
Inner Diameter ◽  
Pressure Transmitter ◽  
Group D ◽  
Fluidization Condition

The present work aimed to identify the defluidization region of a gas-solid fluidized bed system composed by Geldart group D particles using the Gaussian spectral pressure distribution technique, which is based on pressure fluctuation measurements in the plenum. In experiments, the defluidization condition of glass beads with apparent density of 2,450 kg/m3 was induced in a plexiglas column of 0.11 m in inner diameter and 1.0 m in height. The gas-solid behavior close to the incipient fluidization condition was assessed for two fixed bed heights (0.10 and 0.20 m) and two mean sizes of particles (1.55 and 2.18 mm in diameter). The bed was fluidized with air at environment temperature. The experimental equipment was instrumented with a pressure transmitter connected to a data acquisition system in order to record the pressure fluctuations of the gas-solid flow. The results showed that the defluidization region can be detected efficiently by using the Gaussian spectral pressure distribution technique, which contributes for a better control of fluidized bed processes.

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