Quantification of solids flow in a gas–solid riser: single radioactive particle tracking

Bhusarapu, Satish; Al‐Dahhan, Muthanna H.; Duduković, Milorad P.

doi:10.1016/j.ces.2004.07.052

Cited by 47 publications

(35 citation statements)

References 8 publications

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“…This is done by measuring emitted gamma-ray intensities. The RPT technique has been successfully applied to measure and visualize 3D flow fields and turbulence parameters in different multiphase flow systems [11,12,[21][22][23][24][25][26][27][28][29][30][31][32][33]. In this work, RPT has been implemented to assess in detail, for the first time, the scale-up study of spouted beds based on the matching of dimensionless groups [15].…”

Section: The Radioactive Particle Tracking (Rpt) Techniquementioning

confidence: 99%

An advanced evaluation of spouted beds scale-up for coating TRISO nuclear fuel particles using Radioactive Particle Tracking (RPT)

Ali

Al-Juwaya

Al‐Dahhan

2017

Experimental Thermal and Fluid Science

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A set of dimensionless groups has been proposed in the literature by He et al. [He Y. L., Lim C. J., Grace J. R., Scale-up studies of spouted beds, Chemical Engineering Science, 52 (2), 329-339, 1997] to scale-up gas-solid spouted beds while maintaining their hydrodynamics similarity. The literature reported studies do not provide conclusive assessments about this methodology. Therefore, in this work, we have applied an advanced non-invasive radioactive particle tracking (RPT) technique for the first time to evaluate such scale-up methodology by measuring the local solids velocity, normal and shear stresses and the turbulent kinetic energy. The axial and azimuthal averaged radial profiles of solids velocity, normal stresses, shear stresses, and turbulent kinetic energy illustrate that the similarity of the hydrodynamics has not been attained when the proposed set of dimensionless groups has been matched using two sizes of spouted beds of 0.076 m and 0.152 m and sets of operating conditions. The conclusion is consistent with the recent reported findings by measuring cross sectional distribution and radial profiles of solids and gas holdups along the bed height using gamma-ray computed tomography and by the limited point measurements of solids velocity and holdup using optical fiber probe. It is clear that local measurements of hydrodynamic parameters are essential for detailed assessment of scale-up methodologies. The presented results of our work in terms of the components profiles of the particles radial velocities and turbulent parameters are also valuable for benchmarking computational fluid dynamics codes and models.

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Section: The Radioactive Particle Tracking (Rpt) Techniquementioning

confidence: 99%

An advanced evaluation of spouted beds scale-up for coating TRISO nuclear fuel particles using Radioactive Particle Tracking (RPT)

Ali

Al-Juwaya

Al‐Dahhan

2017

Experimental Thermal and Fluid Science

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“…To eliminate the contribution to the tracer dispersion due to sections outside the packed bed, experiments were also performed with a short bed (L = 0.07 m). This deconvolution is permitted because the convection-dispersion equation is linear in concentration, and because the convective fluxes dominate the disperse fluxes at the boundary of deconvolution, i.e., 7 cm into the packed bed [14]. This last requirement was checked by using a colored dye injection: no pulsation or back-andforth movement of the tracer band was observed.…”

Section: Rtd Setupmentioning

confidence: 99%

Dispersion and Holdup in Multiphase Packed Bed Microreactors

et al. 2008

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Liquid holdup and dispersion are reported for a column of 2 mm internal diameter, filled with 0.1 mm spherical particles, for multiphase flows with hydrocarbon liquid flow rates of 10-100 lL/min and nitrogen gas flow rates of 50-1000 lL/min using different tracers with varying diffusion coefficients and vapor pressures. It was found that the liquid holdup (liquid volume/external void volume) was between 0.65 and 0.85, with variations between different experiments and limited impact of flow rate on the holdup. The dispersion characteristics were very similar to single-phase dispersion. The particle Peclet number for dispersion was close to 0.2. This value was of the same order of magnitude -just a factor of two to three lower -as the value that was obtained without gas flow. Tracer volatility did cause the tracer to elude earlier, but did not cause significant additional dispersion. The results suggest that the fluid mechanical interaction between the gas and the liquid was very limited.

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“…To match the dimensioneless variance of the solids residence time distribution (RTD) in the riser, one must first know what that RTD is. We have shown that only CARPT can provide the correct answers and have examined the RTD in various flow regimes, providing a challenge for CFD modelers to generate results in agreement with data (Bhusarapu et al, 2004(Bhusarapu et al, , 2006Bhusarapu, 2005). Once that is accomplished, CFB scaleup can be based on firmer grounds.…”

Section: Innovations In Vertical Scaleupmentioning

confidence: 96%

Challenges and Innovations in Reaction Engineering

Duduković

2008

Chemical Engineering Communications

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The importance of reaction engineering in generating a myriad of products on which developed societies depend is outlined. The challenges of a political, economic, and technical nature that need to be addressed in rendering conversion of raw materials into desired products that are more environmentally friendly and sustainable are briefly discussed. It is shown that multiphase reactors are prevalent in all applications, and improvements in the reactor material and energy efficiencies lead to more environmentally benign processes. This requires, in addition to the selection of green process chemistry, systematic implementation of the multi-scale reaction engineering methodology to accomplish proper reactor type selection and scaleup for commercial applications. It is also illustrated that recent innovations in multiphase reaction engineering basically utilize two key concepts: process intensification (e.g., enhancement in mass and heat transfer rates) and simultaneous reaction and separation. Examples of these are discussed, such as micro-reactors, reactive distillation, etc. It is also shown that commercialization of bench-scale discoveries requires either scaleup in parallel or vertical scaleup. New tools for visualization of opaque multiphase flows and development of appropriate rational phenomenological multiphase reactor models for scaleup and design are also briefly discussed.

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Quantification of solids flow in a gas–solid riser: single radioactive particle tracking

Cited by 47 publications

References 8 publications

An advanced evaluation of spouted beds scale-up for coating TRISO nuclear fuel particles using Radioactive Particle Tracking (RPT)

An advanced evaluation of spouted beds scale-up for coating TRISO nuclear fuel particles using Radioactive Particle Tracking (RPT)

Dispersion and Holdup in Multiphase Packed Bed Microreactors

Challenges and Innovations in Reaction Engineering

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