Fluidization of mixed SiO 2 and ZnO nanoparticles by adding coarse particles

Duan, Hao; Liang, Xin; Zhou, Tao; Wang, Jian; Tang, Wenjiang

doi:10.1016/j.powtec.2014.07.045

Cited by 29 publications

(14 citation statements)

References 25 publications

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“…Therefore, the contact between powders and gas increases and a better suspension of powders arises. The second method involves changing the inherent properties of the particles, either by modifying their surface, like coating the particle surface with nanoparticles [23] or mixing them with other particles that are different in size, density or shape [8,[24][25][26]. The latter method does not need any change in the fluidization column or any extra equipment [8] and is thus particularly attractive.…”

Section: Introductionmentioning

confidence: 99%

The Effect of the Presence of Very Cohesive Geldart C Ultra-Fine Particles on the Fluidization of Geldart A Fine Particle Beds

et al. 2019

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The effect of the presence of ultra-fines (d < 10 μm) on the fluidization of a bed containing fine particles (d < 100 μm), is the subject of this paper. Practically, it can happen due to breakage or surface abrasion of the fine particles in some processes which totally changes the size distribution and also fluidization behaviour. The materials used in this study are both ground calcium carbonate (GCC); fine is CALCIT MVT 100 (Geldart’s group A) and ultra-fine is CALCIT MX 10 (group C). The experimental results for different binary mixtures of these materials (ultra-fines have 30%, 50%, or 68% of the total mixture weight) show that the physical properties of the mixtures are close to those of pure ultra-fine powders. Using mean values of the bed pressure drop calculated from several independent repetitions, the fluidization behaviour of different mixtures are compared and discussed. The fluidization behaviour of the mixtures is non-reproducible and includes cracking, channelling and agglomeration (like for pure ultra-fine powders). Increasing the portion of ultra-fine materials in the mixture causes a delay in starting partial fluidization, an increase in the bed pressure drop as well as a delay in reaching the peak point.

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Section: Introductionmentioning

confidence: 99%

The Effect of the Presence of Very Cohesive Geldart C Ultra-Fine Particles on the Fluidization of Geldart A Fine Particle Beds

et al. 2019

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“…Effect of adding fine particles to improve the fluidization of ultra-fine cohesive beds is investigated by other researchers. In previous publications (e.g., [19][20][21][22]), the authors considered the addition of coarser particles with different origins leading in particular to a different density, size, and surface properties. In contrast, this study considers only mixtures of the same material; the fine and ultra-fine material fractions have the same origin, and they differ only in the particle size distribution.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Very Cohesive Ultra-Fine Particles in Mixtures on Compression, Consolidation, and Fluidization

et al. 2019

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This paper focuses on the effect of ultra-fine ( d < 10 µm) powders in mixtures with fine ( d < 100 µm) bulk material on compression processes and also evaluates the re-fluidization behavior of the compressed bed (history effect). Achieving this goal, different mixtures of fine and ultra-fine Ground-Carbonate-Calcium were compressed at three pressure levels. The results show that by increasing the applied pressure, the compressibility decreases due to change in compaction regime. Subsequently, for the higher pressure, the slope of packing density versus applied stress curves is noticeably different. However, this slope does not depend on the size distribution of mixtures, but on the type of material. Comparing fluidization and re-fluidization curves (bed pressure drop vs. gas velocity) shows an increase in the maximum bed pressure drop ( Δ P p e a k ) for re-fluidization. By increasing the portion of ultra-fine particles in the binary mixture, Δ P p e a k increases in a non-linear manner. Furthermore, the incipient fluidization point moves to a higher gas velocity. After compression, the peak of the bed pressure drop in the re-fluidization test happens at a lower gas velocity than in the initial fluidization test. Thus, the slope of the loading curve is much larger for re-fluidization. The opposite is observed for the unloading curves.

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“…Pulsed fluidized beds have lately attracted a lot of attention towards this end. This belongs to a class of assisted fluidization techniques, whereby the fluidized bed technology is further assisted with a technique to improve the fluidization quality, enhance the bed homogeneity, and promote the deagglomeration [1][2][3][4]. The choice of a suitable assisted fluidization technique in an actual application is nevertheless governed by several issues, for example, energy usage, contamination concerns, and scale-up challenges.…”

Section: Introductionmentioning

confidence: 99%

Effect of Frequency on Pulsed Fluidized Beds of Ultrafine Powders

Ali

Al‐Ghurabi

Ajbar

et al. 2016

Journal of Nanomaterials

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Deagglomeration of ultrafine powders poses an important challenge towards their efficient and effective utilization. In the present study, we investigate the effect of frequency on the hydrodynamics of pulsed fluidized beds of ultrafine powders that show strong agglomeration behavior. We have carefully selected square waves of three different frequencies: 0.05 Hz, 0.10 Hz, and 0.25 Hz. The lowest frequency used here allowed the fluidized bed to settle completely before another pulse was introduced whilst the highest frequency ensured that the bed remained in a state of continuous turbulence between occurrences of consecutive pulses. On the other hand, the intermediate frequency pulse was just sufficient to complete the process of bed collapse before the start of the next pulse. Both local and global bed dynamics in all the three cases were rigorously monitored using fast response pressure transducers. The pressure transient data during the bed collapse were processed using the bed collapse model reported in the literature to compute the effective hydrodynamic diameter of agglomerates. Though there was substantial decrease in the agglomerate size, the effect of the frequency appeared to be rather insignificant as the global pressure transients remained rather insensitive to the change of the fluidization velocity.

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Fluidization of mixed SiO 2 and ZnO nanoparticles by adding coarse particles

Cited by 29 publications

References 25 publications

The Effect of the Presence of Very Cohesive Geldart C Ultra-Fine Particles on the Fluidization of Geldart A Fine Particle Beds

The Effect of the Presence of Very Cohesive Geldart C Ultra-Fine Particles on the Fluidization of Geldart A Fine Particle Beds

The Effect of Very Cohesive Ultra-Fine Particles in Mixtures on Compression, Consolidation, and Fluidization

Effect of Frequency on Pulsed Fluidized Beds of Ultrafine Powders

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