Experimental spray zone characterization in top-spray fluidized bed granulation

Börner, Matthias; Hagemeier, Thomas; Ganzer, Gunnar; Peglow, Mirko; Tsotsas, Evangelos

doi:10.1016/j.ces.2014.05.007

Cited by 31 publications

(13 citation statements)

References 36 publications

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“…Particularly, based on our TFM results, the particles meet the droplets at the boundary of the spraying zone due to their downward velocity. This inconsistency stems from the discrepancy in the solid flow pattern observed by Börner et al and the one predicted in our present study. In fact, since the particle size used in their study falls into Geldart D classification, two vortices are observed in the dense bed.…”

Section: Resultscontrasting

confidence: 99%

“…They claimed that wetting of the particle entering the spray zone from the bottom is selective and imperfect. We note in passing that Börner et al concluded that, in the range of u mf and 4 u mf ( u mf is the minimum fluidization velocity), similar hydrodynamic behavior is observed for both rectangular and cylindrical beds. Thus, the shape of the FB is not essential, motivating studies in rectangular beds that are easier to analyze both with experiments and with simulations.…”

Section: Introductionsupporting

confidence: 64%

“…This necessitates the existence of a high-temperature gradient zone next to the wetting zone . As reported by Turchiuli et al and Börner et al, the size of the wetting zone was tremendously influenced by the FB’s operating parameters. In another study, Maronga and Wnukowski , claimed that the wetting zone can be divided into two subzones: (i) an active-spraying zone situated next to the nozzle and (ii) an active-drying zone located between the acitve-spraying zone and a nonactive zone.…”

Section: Introductionmentioning

confidence: 96%

“…We next review findings from the literature related to these exchange rates. According to Jiménez et al, a higher spray rate induces faster particle circulation and consequently reduces the drying time, as supported by experimental observations of Börner et al Vanderroost et al proposed a mathematical model for particle motion in a fluidized bed coater (FBC). They claimed that their model can predict the solid flow behavior reliably in the absence of atomization air injection.…”

Section: Introductionmentioning

confidence: 97%

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Two-Fluid-Model-Based Full Physics Simulations of Mixing in Noncohesive Wet Fluidized Beds

Askarishahi

Salehi

Radl

2019

Ind. Eng. Chem. Res.

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Mixing in a noncohesive wet fluidized bed was studied using the two-fluid model (TFM) and a zero-dimensional (0D) approach. The employed TFM was extended to simulate droplet deposition on the particles, droplet evaporation, and particle drying. To quantify the bed uniformity, the variance of temperature and the particles’ loss on drying (LoD) field were computed. Subsequently, our TFM simulation data is used to support the assumptions adopted in our 0D model. Specifically, the simulation results suggest the formation of two well-mixed zones: a spraying/wetting zone and a drying zone. Furthermore, it was demonstrated that the 0D model can accurately predict the gas and particle temperatures, as well as the moisture content with a maximum error of 4.3% when the following criteria are met: (i) low enough temperature and LoD variance (i.e., less than 5%); (ii) deep droplet penetration into the bed; (iii) no droplet loss.

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Section: Resultscontrasting

confidence: 99%

Section: Introductionsupporting

confidence: 64%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 97%

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Two-Fluid-Model-Based Full Physics Simulations of Mixing in Noncohesive Wet Fluidized Beds

Askarishahi

Salehi

Radl

2019

Ind. Eng. Chem. Res.

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“…Polymerization, drying, and granulation are a few examples of their applications. [1][2][3][4][5][6] Due to the importance of these contactors, a wide range of experimental techniques has become available to capture their hydrodynamic behavior. [7][8][9][10][11][12][13][14][15] Each experimental technique has its own advantages and disadvantages.…”

Section: Introductionmentioning

confidence: 99%

On the accuracy of Landweber and Tikhonov reconstruction techniques in gas‐solid fluidized bed applications

et al. 2015

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in Wiley Online Library (wileyonlinelibrary.com) As electrical capacitance tomography technique needs a sophisticated reconstruction, the accuracy of two of the most widely used reconstruction techniques (Landweber and Tikhonov) for gas-fluidized bed applications were assessed. For this purpose, the results of two-fluid model simulations were used as an input of reconstruction. After finding the optimum reconstruction parameters for the studied system, it is found that both techniques were able to obtain the radial profile and overall value of average volume fraction very well. Conversely, both methods were incapable to determine bubble sizes accurately especially small bubble sizes, unless the Landweber technique with inverted Maxwell concentration model is applied. The probability distribution of the reconstructed results was also smoother in transition between the emulsion and bubble phases compared to the reality. Finally, no significant differences in noise immunity of these two techniques were observed. V C 2015 American Institute of Chemical Engineers AIChE J, 61: [4102][4103][4104][4105][4106][4107][4108][4109][4110][4111][4112][4113] 2015

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Full‐physics simulations of spray‐particle interaction in a bubbling fluidized bed

2017

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1Numerical simulations of a gas-particle-droplet system were performed using an Euler-2 Lagrange approach. Models accounting for (i) the interaction between droplets and particles, 3 (ii) evaporation from the droplet spray, as well as (iii) evaporation of liquid from the surface 4 of non-porous particles were considered. The implemented models were verified for a packed 5 bed, as well as other standard flow configurations. The developed models were then applied 6 for the simulation of flow, as well as heat and mass transfer in a fluidized bed with droplet 7 injection. The relative importance of droplet evaporation vs. evaporation from the particle 8 surface was quantified. It was proved that spray evaporation competes with droplet deposition 9 and evaporation from the particle surface. Moreover, we show that adopting a suitable surface 10 coverage model is vital when attempting to make accurate predictions of the particle's liquid 11 content. 12

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Experimental spray zone characterization in top-spray fluidized bed granulation

Cited by 31 publications

References 36 publications

Two-Fluid-Model-Based Full Physics Simulations of Mixing in Noncohesive Wet Fluidized Beds

Two-Fluid-Model-Based Full Physics Simulations of Mixing in Noncohesive Wet Fluidized Beds

On the accuracy of Landweber and Tikhonov reconstruction techniques in gas‐solid fluidized bed applications

Full‐physics simulations of spray‐particle interaction in a bubbling fluidized bed

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