Characterization of the internal morphology of agglomerates produced in a spray fluidized bed by X-ray tomography

Dadkhah, Mehran; Peglow, Mirko; Tsotsas, Evangelos

doi:10.1016/j.powtec.2012.05.051

Cited by 57 publications

(28 citation statements)

References 23 publications

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“…A similar piece of work was carried out by Moreno-Atanasio et al [14]. More recently, Dadkhah et al [15,16] characterised the internal morphology of agglomerates produced by a spray fluidised bed using X-ray micro-tomography. The 3D volume images of agglomerates were analysed in terms of porosity, coordination number, coordination angle.…”

Section: Accepted M Manuscriptmentioning

confidence: 85%

3D printed agglomerates for granule breakage tests

Ghadiri

Bonakdar

et al. 2017

Powder Technology

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In the research into agglomeration, a long term barrier is the lack of a universally accepted method to evaluate the breakage propensity of agglomerates. Computer simulation is often used but is limited by the lack of identical, controlled agglomerates to test and validate simple models, let alone replicate the complex structure of real industrial agglomerates. This paper presents work on the characterisation of strength of model test agglomerates prepared by a 3D printing production method enabling fully reproducible structures.Agglomerates were designed using Solidworks 2014 software and printed by an Objet500 Connex 3D printer. Materials with different mechanical properties were used to print the particles and the inter particle bonds, allowing a series of combinations of bond strength, particle strength and agglomerate structure to be tested. Compression and impact tests were performed to investigate the breakage behaviour of the printed agglomerates in terms of agglomerate orientations, bond properties and strain rates. This method will allow more rigorous testing of agglomerate breakage models.

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Section: Accepted M Manuscriptmentioning

confidence: 85%

3D printed agglomerates for granule breakage tests

Ghadiri

Bonakdar

et al. 2017

Powder Technology

View full text Add to dashboard Cite

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“…4). Finally the porosity of the shell is calculated by the usage of different graphical filters and mathematical operations [5]. The temporal evolution of the particle size distribution was determined using a particle size analyzer (Camsizer) of Retsch Company.…”

Section: Methodsmentioning

confidence: 99%

Influence of Granule Porosity during Fluidized Bed Spray Granulation

Hoffmann¹,

Rieck²,

Bück³

et al. 2015

Procedia Engineering

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Fluidized bed spray granulation is an important process for the transformation of liquids into solid materials. Especially product properties like final particle size and structure of the granules are important. These properties are closely related to the selected process parameters such as temperature and spraying rate. By knowing the relationship between the thermal process conditions and resulting particle structure, the final product can be designed according to the wishes of the consumers. In the presented work, a correlation between the thermal process conditions and the achieved shell porosity, which is relevant for the particle structure, is revealed. Therefore two experimental series with different materials (non-porous glass particles and porous alumina) were performed in a lab-scale fluidized bed spray granulator. The lab-plant allows the precise measurement of the inlet and outlet temperatures and moisture contents of the gas. All process parameters were kept constant except the inlet gas temperature and the spraying rate. Although the amount of initial material as well as the amount of injected solution was the same for all experiments, the final particle size distribution and the structure of the formed shell were clearly different. The obtained experimental results were compared with a process model including a new expression for the growth kinetics, which takes into account an acceleration of the growth velocity due to the formation of a porous structure. The used model also considers the separation of the fluidized bed into two different zones, namely the spraying zone and the drying zone. With the given initial process conditions, the model calculates the time evolution of the particle size distribution, the theoretical outlet temperature and the moisture content of the gas. The introduction of the shell porosity into the growth kinetics reduces the underestimation of the particle size in the model, which occurs if the formed layer on the particle surface is assumed to be compact.

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“…Therefore total internal air volume can vary depending on the image segmentation method [21] or the experimental methodology [20]. This section presents indirect validation methods that indicate that the convex hull method described in Section 2.5 gives total internal air volumes that are reasonable.…”

Section: Granule Internal Air Validationmentioning

confidence: 99%

“…(2), is 7.6. Dadkhah et al [21] found that the average coordination number for granules created in a fluid bed ranged from 2.00 to 5.48, with the coordination number increasing as the number of particles within the agglomerate increased. The smaller average coordination numbers are expected due to the fluid bed granules having higher porosity, 52-72% as measured by grayscale dilation.…”

Section: Radial Phase Distributionsmentioning

confidence: 99%

“…Volumetric data has been used in defining the size, shape, coordination number, and fractal dimension of particles along with various aspects of the pore size distribution [21][22][23]. The distribution of binder in granules, however, has not been previously examined, despite its likely strong impact on granule strength, attrition resistance, and disintegration/dissolution.…”

Section: Introductionmentioning

confidence: 99%

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