Catalyst bed dilution for improving catalyst wetting in laboratory trickle-bed reactors

Journal Article · Sun Sep 01 04:00:00 EDT 1996 · AIChE Journal

DOI:https://doi.org/10.1002/aic.690420920· OSTI ID:378002

Al-Dahhan, M H; Dudukovic, M P ^[1]

---

1. Washington Univ., St. Louis, MO (United States). Chemical Reaction Engineering Lab.

The catalyst bed dilution technique has found rather widespread applications as a means of producing reliable and reproducible results for successful scale-up and scale-down when testing commercially used catalyst particles sizes and alternative feedstocks in small-scale laboratory trickle-bed reactors. In such small-diameter laboratory units when the catalyst used in commercial units is employed as the only packing, low liquid velocities lead to incomplete catalyst utilization due to incomplete external catalyst wetting, liquid maldistribution, and wall effects. Diluting the bed with fines on catalyst wetting efficiency, pressure drop, and liquid holdup are quantified. At atmospheric pressure, fines improve the catalyst wetting efficiency by increasing both the pressure drop and liquid holdup. At high-pressure operation, wetting efficiency improves further, whereas pressure drop increases and liquid holdup decreases. In a highly diluted bed (e.g., 2 or more volume fines/l volume catalyst) the improvement in catalyst wetting efficiency is about the same as that achieved in a bed packed according to the recommended procedure, which is based on filling the voidage of the original bed with fines. Trickle beds are widely used in the petroleum (hydrogenation, hydrocracking, hydrodesulfurization, hydrodenitrogenation, alkylation, etc.), petrochemical (hydrogenation, oxidation, etc.), and chemical industries (hydrogenation of higher aldehydes, reactive ammination, liquid-phase oxidation, syngas conversion, etc.), as well as in waste treatment (oxidation of dilute aqueous and organic solutions, etc.), biochemical processes (using immobilized enzymes or cells, etc.), and electrochemical processing.

• OSTI ID: 378002
• Journal Information: AIChE Journal, Journal Name: AIChE Journal Journal Issue: 9 Vol. 42; ISSN AICEAC; ISSN 0001-1541
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
ADDITIVES
CATALYSTS
CHEMICAL REACTORS
CONCENTRATION RATIO
LIQUID FLOW
MATERIALS TESTING
MEASURING METHODS
PERFORMANCE TESTING
USES
WETTABILITY