Studies on Bed Density in a Gas-Vibro Fluidized Bed for Coal Cleaning

Zhou, Chenyang; Dong, Liang; Zhao, Yuemin; Fan, Xuchen

doi:10.1021/acsomega.9b01892

Cited by 21 publications

(13 citation statements)

References 30 publications

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“…The efficacy of pulsed fluidized beds has also been recently investigated in stabilizing the bulk density and expansion of an air dense medium fluidized bed (ADMFB) for carrying out the dry beneficiation of fine coal powder. [ 34,35 ] Pulsed fluidization has also been used for drying because of its superior mass and heat transfer characteristics. For example, Jia et al carried out biomass drying without inerts in a pulsed fluidized bed in conjunction with mechanical vibrations.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of partially collapsing pulsed fluidized bed

2021

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The use of flow pulsation as an effective assisted fluidization technique has been suggested in a number of applications, such as drying of food and pharmaceutical products, dry beneficiation of coal, and deagglomeration of nanopowders, owing mainly to its cost‐effectiveness and ease of implementation. The efficacy of this technique is, however, greatly affected by the frequency of pulsation since it controls the collapse dynamics of the fluidized bed. In this study, using ultrafine hydrophilic nanosilica with strong agglomeration tendencies, the pulsation frequency was controlled to allow only partial collapse of the bed between two successive pulsations while the global and local dynamics in different bed regions were carefully monitored. Besides the usual advantages associated with assisted fluidization techniques, such as lower minimum fluidization velocity, higher bed expansion, and elimination of bed non‐homogeneities, the continuous and intense solid motion imparted by the partial bed collapse caused a more substantial increase in the overall pressure drop than the one obtained with the conventional unassisted fluidization. The results of the frequency domain analysis highlighted the fact that the effect of pulsation event was felt differently in different regions of the bed depending upon the amplitude of the pulsation. These results were further corroborated by the similarity analysis.

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Section: Introductionmentioning

confidence: 99%

Dynamics of partially collapsing pulsed fluidized bed

2021

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“…In a traditional gas-solid fluidized bed, a Geldart B particle-dense [30] medium (0.1-0.4 mm) is generally used as the dense medium for separation; however, Geldart B particles have some limitations [31]. First of all, the emulsion phase of a fluidized bed with Geldart B particles expands less during the process of separation, and the adjustment of emulsification relative to the fluidized bed density plays a crucial role [32].…”

Section: Introductionmentioning

confidence: 99%

Estimation of Bed Expansion and Separation Density of Gas–Solid Separation Fluidized Beds Using a Micron-Sized-Particle-Dense Medium

Fan

Zhou

2021

Separations

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Coal is the dominant energy resource in China. With the Chinese policy of committing to reducing peak carbon dioxide emissions and achieving carbon neutrality, coal separation has recently become a hot topic, especially the fluidized separation of fine particles. In this study, micron-sized particles were introduced to ameliorate the properties of the traditional fluidized bed. The expansion characteristics of the micron-sized-particle-dense medium were explored. A bed expansion prediction model of the micron-sized-particle-dense medium was established, and the prediction error was about 10%, providing a theoretical basis for understanding the distribution characteristics of the bed. This model also helped predict the bed density in the presence of a micron-sized-particle-dense medium, and the prediction accuracy was between 85% and 92%, providing a theoretical basis for selecting and popularizing fluidized beds for industrial separation.

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“…Strategies for improving fluidization hydrodynamics of powders are often known as assisted fluidization techniques. Examples are acoustics [9][10][11][12][13][14], particle-mixing [15][16][17][18][19][20], flow pulsations [21][22][23][24][25][26][27][28][29], and mechanical vibrations [30][31][32][33][34]. In some cases, a combination of two assisted fluidization technique has been suggested [20,35].…”

Section: Introductionmentioning

confidence: 99%

“…The bed is subjected to intense periodic turbulence without requiring any additional energy input because of the change in flow rate caused by pulsation. Consequently, it has been gaining significant attention in literature [21][22][23]. When used to dry pharmaceutical granules, this technique decreases the total time of drying while enhancing bed homogeneity as compared with unassisted fluidization [24].…”

Section: Introductionmentioning

confidence: 99%

Deagglomeration of Ultrafine Hydrophilic Nanopowder Using Low-Frequency Pulsed Fluidization

et al. 2020

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Low-frequency flow pulsations were utilized to improve the hydrodynamics of the fluidized bed of hydrophilic ultrafine nanosilica powder with strong agglomeration behavior. A gradual fluidization of unassisted fluidized bed through stepwise velocity change was carried out over a wide range of velocities followed by a gradual defluidization process. Bed dynamics in different regions of the fluidized bed were carefully monitored using fast and sensitive pressure transducers. Next, 0.05-Hz square-wave flow pulsation was introduced, and the fluidization behavior of the pulsed fluidized bed was rigorously characterized to delineate its effect on the bed hydrodynamics by comparing it with one of the unassisted fluidized bed. Flow pulsations caused a substantial decrease in minimum fluidization velocity and effective agglomerate diameter. The frequencies and amplitudes of various events in different fluidized bed regions were determined by performing frequency domain analysis on real-time bed transient data. The pulsations and their effects promoted deagglomeration and improved homogeneity of the pulsed fluidized bed.

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Studies on Bed Density in a Gas-Vibro Fluidized Bed for Coal Cleaning

Cited by 21 publications

References 30 publications

Dynamics of partially collapsing pulsed fluidized bed

Dynamics of partially collapsing pulsed fluidized bed

Estimation of Bed Expansion and Separation Density of Gas–Solid Separation Fluidized Beds Using a Micron-Sized-Particle-Dense Medium

Deagglomeration of Ultrafine Hydrophilic Nanopowder Using Low-Frequency Pulsed Fluidization

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