Micromixing Characteristics in a Small‐Scale Spinning Disk Reactor

Boodhoo, Kamelia; Al-Hengari, Salah

doi:10.1002/ceat.201100695

Cited by 45 publications

(27 citation statements)

References 21 publications

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“…In relation to other studies, Rousseaux et al (1999) 34 investigated the micromixing efficiency of a sliding-surface mixing device, reporting micromixing times ranging from 1.0 × 10 –2 to 1.0 × 10 –1 s for the studied operational conditions. In a freely spinning disc reactor which is not enclosed by a narrow encasing, Boodhoo and Al-Hengari (2012) 35 investigated the micromixing efficiency for a range of hydrodynamic conditions, and reported improved micromixing behavior (lower segregation index) at high rotational speeds and high feed flow rates. Moreover, they compared the results with a stirred tank at similar conditions, showing improved micromixing at comparable energy inputs.…”

Section: Resultsmentioning

confidence: 99%

Micromixing in a Rotor–Stator Spinning Disc Reactor

Martínez

Eeten

Schouten

et al. 2017

Ind. Eng. Chem. Res.

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This paper presents the micromixing times in a rotor–stator spinning disc reactor. Segregation indices are obtained at different rotational speeds performing the Villermaux–Dushman parallel-competitive reaction scheme. Consequently, the corresponding micromixing times are calculated using the engulfment model, while considering the self-engulfment effect. It was found that the segregation index decreases with an increasing disc speed. Furthermore, for the investigated operational conditions, the estimated micromixing times are in the range of 1.13 × 10–4 to 8.76 × 10–3 seconds, in agreement with the theoretical dependency on the energy dissipation rate of ε–0.5. In a rotor–stator spinning disc reactor it is thus possible to further continue the theoretical trend of decreasing micromixing times with very high levels of energy dissipation rates that are unattainable in traditional types of process equipment.

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Section: Resultsmentioning

confidence: 99%

Micromixing in a Rotor–Stator Spinning Disc Reactor

Martínez

Eeten

Schouten

et al. 2017

Ind. Eng. Chem. Res.

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“…With the disintegration of the film, the hydrodynamics would be different from those in a continuously spreading film and would not be easily defined. Indeed film breakdown at very low flowrates in the SDR has been shown to be responsible for reduced mixing capability of the film [21]. It is envisaged that the RTD which, like mixing, is also dependent on the flow dynamics can be similarly affected.…”

Section: Effect Of Flowrate and Rotational Speedmentioning

confidence: 99%

Online conductivity measurement of residence time distribution of thin film flow in the spinning disc reactor

Mohammadi

Boodhoo

2012

Chemical Engineering Journal

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Spinning disc reactors provide effective continuous flow mixing in highly sheared liquid films flowing under the action of high centrifugal forces generated as a result of the disc rotation. Although the flow is theoretically characterised to be laminar on the basis of the low Reynolds numbers, the film surface is normally covered with numerous ripples which can change the film hydrodynamics and velocity distribution and thereby affect its residence time distribution (RTD) on the rotating disc. The aim of this study is to determine the experimental conditions for which near plug flow behaviour prevails on the spinning disc. Our findings indicate that the higher the disc speed and liquid flow rate and the lower the viscosity of the processing liquid, the closer conditions within the liquid film on the disc approximate to plug flow behaviour. These effects are attributed to the greater degree of turbulence induced in the liquid film as a result of an increased intensity of surface waves, promoting transverse mixing across the film thickness and thus a more uniform velocity profile at any given radial position. The centrifugal force directing the liquid radially to the disc periphery may also play a part in reducing radial dispersion. The texture of the disc surface is also an influential parameter in achieving plug flow on the rotating disc. With flow on a grooved disc, the number of tanks-in-series increased quite significantly under identical operating conditions as those for a smooth disc, confirming that radial dispersion is lowered. One of the explanations for this effect is that the constantly changing topography enabled by the series of concentric grooves across the disc surface offers the opportunity for repeated film detachment and re-attachment which cause induced recirculation or vortices within the film, giving better transverse mixing and eliminating velocity gradients.

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“…Cloud formation was observed, and when feeding into the clear liquid above the cloud, the segregation index increased significantly. Very recently, the micromixing efficiency in a 10-cm spinning disk reactor (SDR) was investigated using the iodide/iodate reaction in a single-phase system by Boodhoo et al [9]. They found that the performance of the SDR was superior to that of the rotating packed-bed when doubling the flow rate, and was much alike to that of the rotor-stator reactor at higher flow rates.…”

Section: Introductionmentioning

confidence: 97%

Micromixing of Solid‐liquid Systems in a Stirred Tank with Double Impellers

et al. 2013

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The effect of solid particles on micromixing has been studied using the competitive iodide/iodate reaction system in stirred, multi-impeller, solid-liquid systems. The influences of particle size, impeller speed, solid holdup, feed position, and energy input have been investigated. The change of the segregation index with the power input was more distinguishable only for the 450-600 lm particles as compared with the large ones, at the same solid holdups. Also, for the small ones, cloud formation was observed at a particle concentration of 12.1 wt %. However, the influence of larger particles of 1-1.25 mm on micromixing was negligible, though both energy input and solid loading were increased. Besides, the optimal feed position was identified, and multiple feeds were also explored.

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Micromixing Characteristics in a Small‐Scale Spinning Disk Reactor

Cited by 45 publications

References 21 publications

Micromixing in a Rotor–Stator Spinning Disc Reactor

Micromixing in a Rotor–Stator Spinning Disc Reactor

Online conductivity measurement of residence time distribution of thin film flow in the spinning disc reactor

Micromixing of Solid‐liquid Systems in a Stirred Tank with Double Impellers

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