Measuring Solids Concentration in Fluidized Systems by Gamma-Ray Absorption

Bartholomew, R. N.; Casagrande, R. M.

doi:10.1021/ie51392a041

Cited by 69 publications

(27 citation statements)

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“…When the axis of the pipe is not vertical, it is clear that the particles will be distributed nonuniformly over the cross section as a result of gravitational sedimentation, so one-dimensional theoretical treatments are inappropriate. Marked segregation of the particles over the cross section, however, occurs even in vertical flow (Bartholomew and Casagrande, 1957; Saxton and Worley, 1970; Yerushalmi et al, 1978; Youchou and Kwauk, 1980; Weinstein et al, 1984; Bader et al, 1988). In some cases, they are found to be concentrated near the pipe wall, while in others large regions of high concentrations, called streamers, extend well into the center of the pipe.…”

Section: Introductionmentioning

confidence: 99%

Developing flow of a gas‐particle mixture in a vertical riser

Pita

Sundaresan

1993

AIChE Journal

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A computational study of steady, developing flow of gas-particle suspensions in a vertical riser has been carried out, using a model based on kinetic theory of granular materials, to understand the role of inlet configuration on the pattern of flow development. Three inlet configurations-uniform inlet, core-annulus flow at the inlet and circumferential injection of secondary gas-were examined. It is found that the inlet configuration can have a profound impact on the rate of segregation of particles to the wall and the internal recirculation. Circumferential injection of gas has a favorable effect on the flow in the sense that it can decrease the extent of internal recirculation.

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Section: Introductionmentioning

confidence: 99%

Developing flow of a gas‐particle mixture in a vertical riser

Pita

Sundaresan

1993

AIChE Journal

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“…This technique has been known and applied for many years. For example, Bartholomew and Casagrande (1957) applied GDT in fluidized vessels with diameters ranging from 6 inches (0.15 m) to 40 ft (12 m). As radiation detection equipment and computers (for tomographic reconstruction) improve these techniques become more accessible to researchers, but widespread application in industry has not yet occurred.…”

Section: Industrial Gamma-densitometry Tomographymentioning

confidence: 99%

Circulating fluidized bed hydrodynamics experiments for the multiphase fluid dynamics research consortium (MFDRC).

Oelfke¹,

Torczynski²,

O’Hern³

et al. 2006

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An experimental program was conducted to study the multiphase gas-solid flow in a pilot-scale circulating fluidized bed (CFB). This report describes the CFB experimental facility assembled for this program, the diagnostics developed and/or applied to make measurements in the riser section of the CFB, and the data acquired for several different flow conditions. Primary data acquired included pressures around the flow loop and solids loadings at selected locations in the riser. Tomographic techniques using gamma radiation and electrical capacitance were used to determine radial profiles of solids volume fraction in the riser, and axial profiles of the integrated solids volume fraction were produced. Computer Aided Radioactive Particle Tracking was used to measure solids velocities, fluxes, and residence time distributions. In addition, a series of computational fluid dynamics simulations was performed using the commercial code Arenaflow™.

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“…[1][2][3][4][5][6] Due to the importance of these contactors, a wide range of experimental techniques has become available to capture their hydrodynamic behavior. [7][8][9][10][11][12][13][14][15] Each experimental technique has its own advantages and disadvantages. In general, all the experimental techniques can be classified into two categories: intrusive and nonintrusive.…”

Section: Introductionmentioning

confidence: 99%

On the accuracy of Landweber and Tikhonov reconstruction techniques in gas‐solid fluidized bed applications

et al. 2015

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in Wiley Online Library (wileyonlinelibrary.com) As electrical capacitance tomography technique needs a sophisticated reconstruction, the accuracy of two of the most widely used reconstruction techniques (Landweber and Tikhonov) for gas-fluidized bed applications were assessed. For this purpose, the results of two-fluid model simulations were used as an input of reconstruction. After finding the optimum reconstruction parameters for the studied system, it is found that both techniques were able to obtain the radial profile and overall value of average volume fraction very well. Conversely, both methods were incapable to determine bubble sizes accurately especially small bubble sizes, unless the Landweber technique with inverted Maxwell concentration model is applied. The probability distribution of the reconstructed results was also smoother in transition between the emulsion and bubble phases compared to the reality. Finally, no significant differences in noise immunity of these two techniques were observed. V C 2015 American Institute of Chemical Engineers AIChE J, 61: [4102][4103][4104][4105][4106][4107][4108][4109][4110][4111][4112][4113] 2015

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Measuring Solids Concentration in Fluidized Systems by Gamma-Ray Absorption

Cited by 69 publications

References 1 publication

Developing flow of a gas‐particle mixture in a vertical riser

Developing flow of a gas‐particle mixture in a vertical riser

Circulating fluidized bed hydrodynamics experiments for the multiphase fluid dynamics research consortium (MFDRC).

On the accuracy of Landweber and Tikhonov reconstruction techniques in gas‐solid fluidized bed applications

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