Assessment of scale‐up dimensionless groups methodology of gas‐solid fluidized beds using advanced non‐invasive measurement techniques (CT and RPT)

Efhaima, Abdelsalam; Al‐Dahhan, Muthanna H.

doi:10.1002/cjce.22745

Cited by 18 publications

(27 citation statements)

References 25 publications

(68 reference statements)

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“…Particle size distribution (PSD), thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR) are prominent in the cluster. [16][17][18][19] The other techniques mostly relate to particle characterization (AAS, EDX, DSC, UPS). [20][21][22][23] The red cluster to the left is remote from the blue and green clusters.…”

Section: Introductionmentioning

confidence: 99%

Experimental methods in chemical engineering: Preface

Patience

2018

Can J Chem Eng

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Chemical engineering research encompasses a plethora of subjects ranging from nanoscale to climate change, from medicine to hazardous waste management, and from electronics and photonics to process intensification, manufacturing, and modelling. The 2017 AIChE meeting included 8000 oral presentations and posters with all these diverse topics. Here we identify experimental methods and instrumentation that straddle these subjects based on Can. J. Chem. Eng. articles published from 2016–2017. Temperature, pH, pressure, and flow rate are the physical properties most researchers report. We identified over 50 experimental techniques, reactor types, and modelling methodologies and show that articles with an experimental focus are more strongly linked than those that concentrate on hydrodynamic modelling and numerical simulation. Spectroscopy dominates instrumental techniques to characterize solids and catalyst properties and we classify 36 instruments according to what property they measure and the scale, nature of the phase, composition, and morphology. A bibliometric analysis grouped the physicochemical properties into three major research clusters centered around solid properties, liquid phase properties, and gas phase and aqueous phase properties. Articles in this special series describe the basic principles of one experimental method or instrument that appears frequently in the journal. Together with a short background, the articles highlight fields of application, assess the sources of error, detection thresholds, and uncertainty. This series provides chemical engineers with a concise, accessible reference guide to help identify and choose appropriate experimental techniques and instruments.

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Section: Introductionmentioning

confidence: 99%

Experimental methods in chemical engineering: Preface

Patience

2018

Can J Chem Eng

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“…The minimum fluidization velocity (U mf ) was measured from the profiles of pressure drop versus gas velocity (U g ) and the results were compared with the predictions of the empirical correlation available in the literature. [22] It was found that the comparison of the values is in good agreement (see Efhaima and Al-Dahhan [23] ). The values were 10 cm/s and 12 cm/s for the 44 cm and 14 cm columns respectively.…”

Section: Methodsmentioning

confidence: 66%

“…The superficial gas velocities used were 1.5–3

U_{m f}

, where the

U_{m f}

is the minimum fluidization velocity. These gas velocities covered the bubbling and turbulent flow regime based on the previous work performed in our laboratory . The static bed height above the distributor was kept constant at H/D = 2 for the two columns.…”

Section: Methodsmentioning

confidence: 99%

“…These gas velocities covered the bubbling and turbulent flow regime based on the previous work performed in our laboratory. [21,[38][39][40] The static bed height above the distributor was kept constant at H/D ¼ 2 for the two columns. RPT technique was implemented on the bed height of H/D ¼ 0.1À2.2 above the gas distributor for the 14 cm diameter column and of H/D ¼ 0.05-2.5 above the gas distributor for 44 cm diameter column as illustrated in Figure 1.…”

Section: Methodsmentioning

confidence: 99%

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Bed diameter effect on the hydrodynamics of gas‐solid fluidized beds via radioactive particle tracking (RPT) technique

Efhaima

Al‐Dahhan

2017

Can J Chem Eng

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The hydrodynamics observed in large‐scale gas‐solid fluidized bed reactors are different from those observed in smaller scale beds. In this study, the effect of bed diameter on the hydrodynamics of gas‐solid fluidized bed reactors has been investigated in two bubbling fluidized beds of 44 cm and 14 cm in diameter using an advanced non‐invasive radioactive particle tracking (RPT) technique. Compressed air at room temperature was used as the gas phase, and the solid was glass beads with a particle size of 210 μm (Geldart‐B) and density of 2.5 g · cm−3. Particle velocity field, Reynolds stresses, normal stresses, turbulent kinetic energy, and axial and radial eddy diffusivities were measured in two beds at gas velocities of 1.5 Umf, 2 Umf, and 3 Umf. Experimental results showed that the bed scales have a significant effect on some of these hydrodynamic parameters where the magnitude of solids velocity is much higher in the larger bed and the solids mixing and diffusion of particles are increased by increasing the column diameter.

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“…Eng. published 22 articles on fluidized beds and the top 3 concentrated on modelling: hydrodynamics of slot‐rectangular spouted beds; sorption enhanced steam methane reforming in binary fluidized beds; and scale‐up dimensionless groups derived from non‐invasive measurements . The three articles in Can.…”

Section: Applicationsmentioning

confidence: 99%

Experimental methods in chemical engineering: Reactors—fluidized beds

et al. 2019

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Industry relies on fluidized beds to synthesize chemicals (acrylonitrile, maleic anhydride, titanium dioxide, vinyl chloride), combust coal, dry powders, and treat waste. Fluidized bed folklore declares that they are hard to scale‐up and the gas phase is backmixed. Commercial failures that disregard standard design criteria around powder management, gas/solids injection, and mixing reinforce this belief. However, engineers select fluidized beds for processes that are impractical with conventional technologies to achieve economies of scale for highly exothermic, endothermic, or explosive reactions, for catalysts that deactivate in seconds (or minutes), and for chemistry that requires multiple dosing cycles. Failures are more frequent for these challenging applications. For this reason, researchers study reaction kinetics in fixed beds despite internal mass transfer limitations and axial and radial temperature and concentration gradients. Fluidized bed hydrodynamics vary with powder properties (particle diameter, size distribution, density, sphericity), operating conditions (gas density, viscosity, temperature, pressure), reactor geometry (diameter, height, mass, grid geometry). The minimum fluidization velocity (Umf) is a property that identifies the transition from the fixed bed regime to the fluidized bed regime and equals the gas velocity at which the upward drag force equals the weight of the powder. At the experimental scale, fluidized beds operate isothermally, solids are completely backmixed, and the gas phase is close to plug flow (Ug<-0.25em3Umf). Here, we describe the relationship between powder properties and fluidization quality, list experimental techniques, describe recent applications, and gas phase hydrodynamics and uncertainties.

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Assessment of scale‐up dimensionless groups methodology of gas‐solid fluidized beds using advanced non‐invasive measurement techniques (CT and RPT)

Cited by 18 publications

References 25 publications

Experimental methods in chemical engineering: Preface

Experimental methods in chemical engineering: Preface

Bed diameter effect on the hydrodynamics of gas‐solid fluidized beds via radioactive particle tracking (RPT) technique

Experimental methods in chemical engineering: Reactors—fluidized beds

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