Hydrodynamics and mixing of solids in a recirculating fluidized bed

Chesonis, D. Corleen; Klinzing, George E.; Shah, Yatish T.; Dassori, Carlos G.

doi:10.1021/ie00105a008

Cited by 18 publications

(7 citation statements)

References 5 publications

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“…Most authors have added coarse particles to a circulating fluidized bed of fine particles with a different solids density (Chesonis et al, 1990;Nowak, 1990;Bi et al, 1992: Ijichi et al, 1992Bai et al, 1994;Jiang et al, 1994;Nakagawa et al, 1994). For a mixture of fine particles (FCC.…”

Section: Aiche Journalmentioning

confidence: 99%

Factors affecting solids segregation in circulating fluidized‐bed riser

Hirschberg

Werther

1998

AIChE Journal

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Section: Aiche Journalmentioning

confidence: 99%

Factors affecting solids segregation in circulating fluidized‐bed riser

Hirschberg

Werther

1998

AIChE Journal

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“…Fig. 5 and Table 3 show a comparison between the correlations and u tr90 measured in this and previous studies [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. The correlation in Eq.…”

Section: Resultsmentioning

confidence: 70%

“…Previous studies proposed relationships between the particle Reynolds number (Re tr90 =d p u tr90 ρ g /μ) at u tr90 and the Archimedes number (Ar=gd p 3 ρ g (ρ s −ρ g )/μ 2 ), as listed in Table 2 [10,11,14,16,18,19]. However, the size of the fluidized-bed seemed to affect Re tr90 appreciably, and based on experimental data from present and previous studies [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19], Re tr90 is written as:…”

Section: Methodsmentioning

confidence: 89%

“…In a vertical fluidized-bed, the transport velocity was studied as the transition velocity between the low-velocity fluidization at which most particles stay in the bed and the transport operation of particles [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17], which refers to the minimum velocity for the transport mode of fluidization. Several correlations for the velocity as a function of the gas and particle properties have also been reported in literature [10,11,14,16,18,19].…”

Section: Introductionmentioning

confidence: 99%

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Effects of angle on the transport velocity in an inclined fluidized-bed

Khurram

Choi

Won

et al. 2015

Korean J. Chem. Eng.

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The transport velocity (u tri ) in an inclined fluidized-bed was investigated by varying the bed angle relative to the horizontal plane (0 o -90 o ), the particle diameter (0.021-0.925 mm), and density (1,272-4,503 kg/m 3 ). This study employed the emptying time method to determine the transport velocity. The transport velocity for the vertical fluidized-bed (u tr90 ) was revealed to increase appreciably with the aspect ratio of the fluidized-bed. The transport velocity decreased as the bed angle increased. The ratio of the transport velocity to that for the vertical bed (u tri /u tr90 ) decreased with an increase in either the bed angle or the ratio of the particle diameter (d p ) to the critical particle diameter (d p * ), i.e., the maximum particle diameter at which the sum of the interparticle adhesion forces had a dominant influence on particle entrainment. Correlations for the transport velocity according to the bed angle relative to the horizontal plane were proposed successfully, based on the experimental data.

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“…Irradiating solids and detecting the gamma ray emission or bremsstrahlung radiation with scintillating NaI detectors is the most effective method for the solids phase . Other techniques for solids include injecting salt or other sorbents and followed by sampling at different points in the reactor and fluorescent and ferromagnetic particles …”

Section: Introductionmentioning

confidence: 99%

Experimental methods in chemical engineering: Residence time distribution—RTD

2020

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Reactor performance, solids‐(gas)‐mixing, flow through porous media, distillation columns, or through granulators improve as the fluid dynamics approach ideal plug flow. The residence time distribution (RTD) is a diagnostic measure of how close fluid flow approaches ideal conditions. The technique introduces a step change to the inlet concentration—a Dirac‐δ function, Heaviside step function, or a rectangular pulse (bolus)—while high frequency detectors monitor the concentration along the vessel and/or at the exit. The effluent concentration profile spreads due to the variance in the process lines leading to the vessel and at the exit, the detector response, and the system. We quantify how much each of these contributes to the overall variance in a fluidized bed with 9 g of fluid cracking catalyst in 8 mm diameter quartz tubes. The injection variance is lowest for a GC sample loop configuration, compared to a 3‐way valve or 4‐way valve geometry. RTD measurements detect bypassing due to dead zones in vessels and the axial‐dispersion model and continuous stirred‐tank model to characterize deviation from plug flow. However, when the contribution to variance from the ancillary lines and detector is large compared to the system, the uncertainty in the model parameters is high. Research on RTD fundamentals concentrate on boundary conditions while, here, we focus on experimental errors: mechanical, physicochemical mathematical, and instrumental.

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Hydrodynamics and mixing of solids in a recirculating fluidized bed

Cited by 18 publications

References 5 publications

Factors affecting solids segregation in circulating fluidized‐bed riser

Factors affecting solids segregation in circulating fluidized‐bed riser

Effects of angle on the transport velocity in an inclined fluidized-bed

Experimental methods in chemical engineering: Residence time distribution—RTD

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