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

Abstract

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.

Parallel hydrogenation for the quantification of wetting efficiency and liquid–solid mass transfer in a trickle‐bed reactor

“…As expected, hydrodynamic multiplicity is the most severe at low liquid velocities (±10–15% variation), where liquid flow in Levec prewetted beds tend to channel 24. Wetting efficiency results for the Levec prewetted operation agree well with the correlation of Julcour‐Lebigue et al19 The experimental data that was used in this correlation was generated in Levec prewetted beds.…”

“…Other methods require correlations for liquid–solid mass transfer to estimate wetting efficiency 16, 17. Recently, Baussaron et al18 generated an extensive amount of wetting efficiency data obtained from a colorimetric method, which was later expanded and correlated by Julcour‐Lebigue et al19…”

Analysis of catalyst wetting efficiency influence on performances of industrial TBR for hydro desulfurization and hydro de aromatization reactions

“…Efektivna ovlaženost katalizatora se izračunava pomoću izraza koji su dati u tabeli 2. Izrazi preuzeti iz literature [6][7][8][9][10][11], dobijeni su različitim metodama Tabela 2. Izrazi za izračunavanje ovlaženosti korišćeni u modelu 4.…”

“…Izrazi za efektivnu ovlaženost sloja katalizatora dobijenim po El-Hisnawi [8], Herkowitz [9] i Julcour [11], katalitički sloj je ovlažen tokom celog procesa, dok jednačine Duduković [6], Burdhardt [7] i Ring [10], predviđaju potpuno isušivanje katalitičkog sloja u drugoj polovini reaktora. Ranije je pokazano da stepen ovlaženosti katalizatora veoma utiče na brzinu hemijske reakcije [12] i da se smanjenjem količine tečne faze u reaktoru ubrzavaju hemijske reakcije i postiže intenzifikacija procesa [13,14].…”

Pore-network modeling of trickle bed reactors: Pressure drop analysis

“…The flow also depends on the physical properties of fluids and interfaces. Local flow characteristics as the wetting efficiency of catalyst surface or the thickness of liquid film have been studied following various experimental and numerical approaches [2,3]. At the opposite extremity of the involved scales, the technology of distribution devices ($m) is also an important field of research and development [4].…”