Modeling of trickle-bed reactors at low liquid flow rates

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1987

OSTI ID:7162792

Beaudry, E G

Models, describing the performance of trickle-bed reactors at low gas and liquid mass velocities, are derived and compared to experimental data. At low liquid velocities, the catalyst particles are assumed to be incompletely externally wetted. The inactively wetted surfaces are assumed to provide a small mass-transfer resistance to the gas reactants and a large resistance to nonvolatile reactants. Experimental data are presented comparing the three modes of packed-bed-reactor operation for the hydrogenation of {alpha}-methylstyrene in n-hexane. Countercurrent and cocurrent downflow of gas gas and liquid reactants perform identically up to the flooding point and are nearly independent of the gas flow rate. Cocurrent-upflow performance improves with increasing gas flow rate but is independent of the liquid flow rate. Liquid downflow outperforms cocurrent upflow for the tested gas-limited system, except at the highest gas flow rate and at the lowest liquid flow rates. The overall effectiveness factor in a partially wetted trickle-bed reactor is derived for a gas-limited reaction. The distribution of the nonvolatile zero-order reactant is accounted for and its influence on the reaction rate within partially wetted pellets is shown. The model weights the contributions of inactively wetted, half-wetted, and completely actively wetted infinite slabs. After the selection of mass-transfer and wetting-efficiency correlations from the literature, the model predictions compare favorably to the above experimental data for liquid downflow and to the data of other hydrogenations found in the literature.

• Research Organization: Washington Univ., St. Louis, MO (USA)
• OSTI ID: 7162792
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020400* -- Petroleum-- Processing
ALKANES
ALKYLATED AROMATICS
AROMATICS
CATALYSTS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHEMICAL REACTORS
FLOW RATE
FLUID FLOW
GAS FLOW
HEXANE
HYDROCARBONS
HYDROGENATION
KINETICS
LIQUID FLOW
MASS TRANSFER
MATHEMATICAL MODELS
ORGANIC COMPOUNDS
PACKED BED
REACTION KINETICS
STYRENE
WETTABILITY