Effect of fluid properties on dispersion in flow through packed beds

Carvalho, J.R.F. Guedes de; Delgado, J. M. P. Q.

doi:10.1002/aic.690490808

Cited by 49 publications

(21 citation statements)

References 26 publications

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“…Order of magnitude estimates can safely be made using 10-20 particle diameter to define an equilibrium stage (or tank-in-series). [24]. For this study f G = 100 lL/min.…”

Section: Dispersion Characteristicssupporting

confidence: 41%

“…10 shows the Pe p values for cumene for single liquid phase and for cumene, hexane and methyl stearate for multiphase (gas flow rate, f G = 100 lL/min) as a function of the Pe M . The results of Guedes de Carvalho and Delgado [24] for single liquid phase are also plotted in the same graph. Even though the ratio of column diameter to particle diameter is different (75 for Guedes de Carvalho and Delgado and 20 for this work) and this work was done with smaller particles (100 lm vs. 625 lm), the single-phase results agree well with their data: for Pe M = 100, they find Pe P = 0.42 for Sc = 1930, with Pe P dropping slightly with increasing Sc.…”

Section: Dispersion Characteristicsmentioning

confidence: 40%

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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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“…Order of magnitude estimates can safely be made using 10-20 particle diameter to define an equilibrium stage (or tank-in-series). [24]. For this study f G = 100 lL/min.…”

Section: Dispersion Characteristicssupporting

confidence: 41%

Section: Dispersion Characteristicsmentioning

confidence: 40%

Dispersion and Holdup in Multiphase Packed Bed Microreactors

et al. 2008

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“…Decrease tendency may be attributed to the influence of the top and bottom boundaries to the vertical displacement of particles. In order to illustrate the spatial variance of particle crowd, spatial moments were introduced (Tompson and Gelhar, 1990; Fernàndez-Garcia et al, 2005a): (12) where m k p is the mass assigned to the k-th particle, X G,i is the first order spatial moment and means the center of mass of particles,  ij is the second order spatial moments associated with the distribution of particles at a certain time, NP t is the number of particles in the system at time t, and X k p,i is the i-component of the k-th particle location. Ensemble means of the second order spatial moments were computed as: (13) where S ij is the second order spatial moments associated with the distribution of particles and variables in angle brackets refer to the ensemble mean across all realizations.…”

Section: Effect Of the Heterogeneity On The Variation Of Macrodispersmentioning

confidence: 43%

Random walk particle tracking approach to assess 3-D macrodispersion in heterogeneous aquifers

Inoue

Tanaka

2016

JGS Special Publication

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A series of solute transport simulations in physically heterogeneous aquifers were conducted to assess the impacts on macrodispersion under saturated flow conditions. The aquifer system of concern relied on the hydrogeological data in a site in the Netherlands and was generated geostatistically as randomly correlated hydraulic conductivity. Ensemble computations in 100 realizations were based upon random walk particle tracking linked with temporal moments to estimate three macrodispersivities. The results showed the scale dependence of macrodispersivities and the asymptotic nature of longitudinal macrodispersivity. From a practical standpoint, the simulations demonstrated that control plane and its middle element provide almost identical macrodispersivity estimates in terms of transverse mixing, but differ markedly from estimates of longitudinal mixing.

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“…The thermodynamic equilibrium constant for a non-ideal liquid phase was calculated with the UNIFAC method using Aspen Properties version 12.1. The Pé clet number for the gas phase, Pe g , was estimated from literature of single gas-phase dispersion in packed beds correcting for the experimental liquid hold-up value (de Carvalho and Delgado, 2003).…”

Section: Mathematical Modelmentioning

confidence: 42%