Trickle Bed Wetting Factors From Pressure Drop And Liquid Holdup Measurements

Luciani, Yanina; González-Mendizabal, Dosinda; Pironti, F. F.

doi:10.1080/00986440214583

Cited by 4 publications

(4 citation statements)

References 26 publications

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“…Conversely Luciani et al reported an improved wetting of the particles when increasing the concentration of carboxymethyl cellulose in water, but as the solutions exhibited also a rather lower surface tension (and thus a better expected spreading of the liquid), they could not discriminate between the influence of each parameter separately.…”

Section: Resultsmentioning

confidence: 94%

Measurements and Modeling of Wetting Efficiency in Trickle-Bed Reactors: Liquid Viscosity and Bed Packing Effects

Julcour-Lebigue

Augier

Maffre

et al. 2009

Ind. Eng. Chem. Res.

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An experimental parametric study on wetting efficiency is reported which evaluates the influence of liquid viscosity, as well as the effect of particle size(/shape) and bed porosity (ε B ), separately. A 10-fold increase of liquid viscosity improves slightly catalyst wetting (by about 10%), while an increase of either bed porosity or particle size has the opposite effect. Wetting efficiency is reduced by about 0.1 for an increase of ε B from 0.38 and 0.40 due to a change of particle size from 1.8 to 7 × 10 -3 m while the decrease is only 0.05 for a similar variation of ε B (0.38-0.41) with the same particles. The effect of particle shape (cylindrical/trilobe extrudates or spheres) appears very small in the investigated conditions. A new correlation for wetting efficiency is proposed, using a bounded function and only three dimensionless groups (liquid Froude and Morton numbers and bed porosity). This correlation is able to predict wetting efficiency with a very good precision on a large database, provided wetting liquids are used. Adding fines in the fixed bed is also examined, and its positive effect can be correlated with the size ratio between catalyst particles and fines.

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Section: Resultsmentioning

confidence: 94%

Measurements and Modeling of Wetting Efficiency in Trickle-Bed Reactors: Liquid Viscosity and Bed Packing Effects

Julcour-Lebigue

Augier

Maffre

et al. 2009

Ind. Eng. Chem. Res.

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Section: Experimental Databasesmentioning

confidence: 99%

“…In addition to the wetting efficiency data presented above, measurements with the Levec-prewetting method have been reported in the literature. − , From Luciani et al the wetting efficiencies measured with CMC-solutions are excluded, since Baussaron et al have shown that with fluids other than air and water, the method severely overpredicts the wetting efficiency. In González-Mendizabal et al the prewetting method is not reported, but in light of their later work , it is likely that the Levec-prewetting method has been used and thus the parts of their data we could obtain is included in the Levec-prewetted database. Wetting efficiencies from the Levec-prewetted experiments were not included in the model optimization or into the model performance analysis, since in a Levec-prewetted bed flow structure is more dependent on flow history, whereas the Kan-prewetting method results in more repeatable flow behavior.…”

Section: Experimental Databasesmentioning

confidence: 99%

“…The first two have been subjects of research for decades, but the importance of the wetting efficiency was only thoroughly acknowledged in the last half of the 1970s . After that, research on wetting efficiency has been extensive. − The main concern has, however, been on wetting efficiency correlations or on the effect of wetting efficiency on reactor performance, and not on how to relate wetting efficiency to the modeling of packed-bed hydrodynamics. On some occasions the wetting efficiency has been used to emphasize the effect of the capillary force on liquid distribution, , but the “double-slit” , and the “four-slit” models are so far the only hydrodynamic models having wetting efficiency incorporated within them.…”

Section: Introductionmentioning

confidence: 99%

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Improved Hydrodynamic Model for Wetting Efficiency, Pressure Drop, and Liquid Holdup in Trickle-Bed Reactors

Lappalainen

Alopaeus

Manninen

et al. 2008

Ind. Eng. Chem. Res.

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An improved hydrodynamic model is developed for estimating wetting efficiency, pressure drop, and liquid holdup in trickle-bed reactors. The model is based on the hydrodynamic model presented in Alopaeus et al.[Alopaeus, V.; Hynynen, K.; Aittamaa, J.; Manninen, M. Modeling of Gas-Liquid Packed-Bed Reactor with Momentum Equations and Local Interactions Closures. Ind. Eng. Chem. Res. 2006, 45, 8189.], which is extended to take into account partial wetting of the packing. In addition, the applicability of the 1D model for three-dimensional situations is considered in the process of model development. The wetting efficiency model is formulated on the basis of dimensional analysis and carrying out systematic tests with varying combinations of dimensionless groups. In addition, the wetting efficiency model is not evaluated solely on the wetting efficiency data, but also it is tested systematically with the hydrodynamic model. Furthermore the consistency of the model characteristics to common experimental observations is discussed. Finally, the model's ability to predict wetting efficiency, dimensionless pressure drop, and liquid saturation was compared to other existing models and improvements were found in all areas. The resulting hydrodynamic model can be used equally as a tool for design and modeling of large scale industrial reactors as well as a tool for complicated threedimensional simulations.

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Experimental characterization of dynamics of bed‐scale liquid spreading in a trickle bed

Saxena,

Gulia,

Augier

et al. 2024

AIChE Journal

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We report measurements performed to understand the effects of gas (QG) and liquid (QL) flow rates, surface tension (σGL), liquid viscosity (μL), and particle diameter (dp) on dynamics of local liquid spreading, pressure drop, and overall liquid holdup in a pseudo‐2D trickle bed. We show that an increase in the gas‐phase inertia leads to a decrease in the lateral liquid spreading, whereas an increase in the liquid‐phase inertia leads to an increase in the lateral liquid spreading. We also show that an increase in dp causes a reduction in the lateral liquid spreading. Using dimensionless numbers (AB and We), we propose a regime map showing contributions of different forces to the local liquid spreading. We show that the interplay between the inertia and capillary forces governs the liquid distribution near the inlet, whereas the relative contribution of gravitational force increases toward the outlet. Finally, we propose a relation between AB and We for “bed‐scale” liquid spreading.

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Trickle Bed Wetting Factors From Pressure Drop And Liquid Holdup Measurements

Cited by 4 publications

References 26 publications

Measurements and Modeling of Wetting Efficiency in Trickle-Bed Reactors: Liquid Viscosity and Bed Packing Effects

Measurements and Modeling of Wetting Efficiency in Trickle-Bed Reactors: Liquid Viscosity and Bed Packing Effects

Improved Hydrodynamic Model for Wetting Efficiency, Pressure Drop, and Liquid Holdup in Trickle-Bed Reactors

Experimental characterization of dynamics of bed‐scale liquid spreading in a trickle bed

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