Effect of particle type on the mechanisms of break up of nanoscale particle clusters

Özcan-Taşkın, N. Gül; Padron, Gustavo A.; Voelkel, Adam

doi:10.1016/j.cherd.2008.12.012

Cited by 59 publications

(30 citation statements)

References 10 publications

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“…These support that aggregates, which are the smallest fragments, are eroded off the surface of agglomerates during processing. These results relating to both the mechanism of breakup and the smallest attainable size are in line with our previous findings (Bałdyga et al, 2008a;Özcan-Taşkin et al, 2009;Padron et al, 2008) and it may therefore be anticipated that for this test system, breakup will occur through erosion with other rotor-stator designs as well. …”

Section: Mechanism Of Break Up and The Finest Attainable Sizesupporting

confidence: 79%

Comparative performance of in-line rotor-stators for deagglomeration processes

Özcan-Taşkın

Padron

Kubicki

2016

Chemical Engineering Science

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In-line rotor-stators are used for a wide range of power intensive dispersion applications, including the breakup of immiscible liquid droplets or agglomerates. This study, performed within the DOMINO project at BHR Group, aimed at studying the performance of three different rotor-stator head designs for deagglomeration processes. A given test system, nanoscale silica particles-in-water, was used to identify the mechanism and kinetics of break-up and determine the smallest attainable size. Three rotorstator head designs used were the GPDH-SQHS and EMSC screens from Silverson and Ytron Z-Lab from Ytron. These in-line rotor-stators were used in the recirculation loop of a stirred tank with a total dispersion volume of 100 litres. Power input and residence time were varied by changing the rotor speed and dispersion flow rate. Breakup was found to occur through erosion regardless of the operating conditions or rotor-stator design. The smallest fragments obtained were aggregates, rather than primary particles, and these were of a mean diameter of 150-200 nm; also independent of the operating conditions or rotor-stator head design. With a given rotor-stator operated at a given flow rate, increasing the rotor speed and hence the power input increased the break up kinetics. For a given design at a given specific power input, whilst the break up rate per tank turnover decreased when the flow rate was increased, the total processing time could be reduced. There were differences in the volume of the mixer head and chamber volumes; in addition, a smaller flow rate range could be covered with the Ytron design. Comparison of the different designs was therefore not straightforward. It could however be shown that the rotor-stator designs with a high number and small size of holes and/or gaps have a faster break up rate.

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Section: Mechanism Of Break Up and The Finest Attainable Sizesupporting

confidence: 79%

Comparative performance of in-line rotor-stators for deagglomeration processes

Özcan-Taşkın

Padron

Kubicki

2016

Chemical Engineering Science

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“…The use of rotor-stator mixers [48] and saw-tooth impellers [26] in an STR are relatively effective, in each case rotating at very high speeds to give extremely large e T;max . In general, higher energy intensive devices than STRs are required for deagglomeration [49].…”

Section: Solid-liquid Systemsmentioning

confidence: 99%

Stirring and Stirred‐Tank Reactors

Nienow

2014

Chemie Ingenieur Technik

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Stirred-tank reactors are used throughout the process industry. They are not only applied in the chemical industry, but also in newer industrial sectors, such as biologics, pharmaceuticals, nanotechnology, and regenerative medicine. Certain features have not changed for many years, but the understanding of the physical processes occurring within has greatly increased. Since knowledge of the interaction between the physics of mixing, single-or multiphase, and the underlying science is critical, the physical processes of mixing/stirring are considered as they developed over the last~75 years.

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“…High shear mixers (HSMs), with the characteristics of high rotor tip speeds, high shear rates, and highly localized energy dissipation rates near the mixing head, have been widely utilized in the emulsification, suspension, and grinding processes in food, cosmetic, and chemical industries, and have great potential to intensify chemical reactions with fast inherent reaction rates but relatively slow mass transfer . Compared with batch HSMs, in‐line teethed HSMs have the advantages of continuous operation, short residence time, and relatively high throughput.…”

Section: Introductionmentioning

confidence: 99%

LDA measurements and CFD simulations of an in‐line high shear mixer with ultrafine teeth

Cheng

et al. 2013

AIChE Journal

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Hydrodynamics of a pilot-scale in-line high shear mixer (HSM) with double rows of ultrafine rotor and stator teeth, including the velocity profiles and power consumptions, were measured using laser Doppler anemometry and a torque transducer, respectively. Computational fluid dynamics simulations were conducted using the standard k-e turbulence model with first-and second-order accuracy and large eddy simulation (LES) with the standard Smagorinsky-Lilly subgrid scale model. Predictive capabilities of the different turbulence models and discretization schemes were assessed based on the experimental data. It is found that the current LES can predict accurately the flow patterns for the strongly rotating and locally anisotropic turbulent flows in the complex in-line HSM. The results obtained are fundamental to explore potential applications of the in-line teethed HSMs to intensify chemical reaction processes.

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Effect of particle type on the mechanisms of break up of nanoscale particle clusters

Cited by 59 publications

References 10 publications

Comparative performance of in-line rotor-stators for deagglomeration processes

Comparative performance of in-line rotor-stators for deagglomeration processes

Stirring and Stirred‐Tank Reactors

LDA measurements and CFD simulations of an in‐line high shear mixer with ultrafine teeth

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