Visualizing fluidized beds with X-rays

Franka, Nathan P.

doi:10.31274/rtd-180813-16571

Cited by 12 publications

(22 citation statements)

References 64 publications

(173 reference statements)

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“…To compare the fluidization characteristics, the chosen particles must fall within the same fluidization category. The particle size between the compared materials follows that of Franka (2008) and corresponds to 500-600 μm. This size range is chosen because of its availability and low cost.…”

Section: Materials Selection and Preparationmentioning

confidence: 95%

“…These two images are used for a linear normalization calibration discussed in the following section. (Franka, 2008). For this study, the location of the detectors remained constant, therefore the COR is the same for all the experiments and in this case is 379.…”

Section: Methodsmentioning

confidence: 99%

“…They are commonly employed in noninvasive techniques because they are safer than other nuclear based techniques which cannot be turned on and off at will, have high resolution, and can be controlled by varying the voltage or current to improve penetration or contrast (Franka, 2008). X-rays are produced by accelerated electrons emitted from a heated cathode; the electrons hit an anode producing a deceleration of the electrons and an emission of electromagnetic radiation.…”

Section: Noninvasive X-ray Techniquesmentioning

confidence: 99%

“…In XPTV, the fluid is seeded with X-ray absorbing particles with similar density to the fluid. Since two projections are imaged simultaneously, three dimensional velocity profiles can be generated (Franka, 2008). polymethylmethacrylate.…”

Section: X-ray Stereographymentioning

confidence: 99%

“…For this study, three different materials were selected using the four criteria specified by Franka (2008). These four criteria were: (i) fluidization behavior, (ii) size range, (iii) density, and (iv) aspect ratio.…”

Section: Materials Selection and Preparationmentioning

confidence: 99%

See 4 more Smart Citations

Bed height and material density effects on fluidized bed hydrodynamics

Escudero

Heindel

2011

Chemical Engineering Science

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Section: Materials Selection and Preparationmentioning

confidence: 95%

Section: Methodsmentioning

confidence: 99%

Section: Noninvasive X-ray Techniquesmentioning

confidence: 99%

Section: X-ray Stereographymentioning

confidence: 99%

Section: Materials Selection and Preparationmentioning

confidence: 99%

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Bed height and material density effects on fluidized bed hydrodynamics

Escudero

Heindel

2011

Chemical Engineering Science

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Local time-averaged gas holdup in fluidized bed reactor using gamma ray computed tomography technique (CT)

Efhaima

Al‐Dahhan

2015

Int J Ind Chem

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Many invasive and non-invasive techniques have been used to analyze the hydrodynamics of fluidized beds. In this study, the effect of superficial gas velocity and bed particle density on the hydrodynamics of gas-solid fluidized beds was investigated by using a cylindrical plexiglas fluidized bed column, 14 cm in diameter. Air at room temperature was used as the fluidizing gas and two different Geldart type-B particles were used: glass beads and copper particles with material densities of 2.5 and 5.3 g/cm 3 , respectively, with the same size particle, 210 lm. To measure the time-averaged cross-sectional gas and solid holdup distribution, gamma ray computed tomography was used for the first time as a non-invasive technique instead of using X-rays (due to the height attenuation of the copper particles). The results show that gas holdup increases by increasing the superficial gas velocity, and decreasing the particle density increases the gas holdup in the bed.

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Review of noninvasive methods to characterize granular mixing

Nadeem

Heindel

2018

Powder Technology

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Granular mixing is a common process observed in a variety of industries such as construction, chemical processing, food handling, and cosmetics and pharmaceutical manufacturing. Over the years several methods have been devised to characterize granular mixing and to provide information on the quality of the mixture as well as mixing end points. In this work, three different noninvasive measurement categories are reviewed, namely: velocimetric, spectroscopic, and tomographic techniques. Velocimetric techniques such as Particle Image Velocimetry (PIV) and Radioactive particle tracking (RPT) are able to provide the trajectories and velocities of individual particles during the mixing process. Spectroscopic techniques focus on the chemical composition of the sample and are well suited for applications where there is little difference in the physical properties of the constituents such as particle size and density. Tomographic techniques such as X-ray computed tomography (CT) and Magnetic Resonance Imaging (MRI) provide information such as the spatial distribution of the different constituents in the sample and are useful in determining dead zones and inhomogeneities. A few other techniques are also discussed, particularly passive acoustic methods which, though can neither provide spatial distribution nor individual particle trajectories, are still useful and can be employed to determine mixing end points. The objective of the work is to provide a comparative assessment of the various noninvasive techniques and discuss their ability to effectively characterize the mixing process. The reported techniques will be reviewed thoroughly based on their functionality, viability, and characterization capability. The advantages and disadvantages of the various techniques are summarized and a comparison of the utility of the techniques in various applications is discussed.

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Visualizing fluidized beds with X-rays

Cited by 12 publications

References 64 publications

Bed height and material density effects on fluidized bed hydrodynamics

Bed height and material density effects on fluidized bed hydrodynamics

Local time-averaged gas holdup in fluidized bed reactor using gamma ray computed tomography technique (CT)

Review of noninvasive methods to characterize granular mixing

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