Bed Expansion in Three-Phase Fluidization

Bed expansion in three-phase fluidization was determined for three sizes of commercial cobalt-molybdate extrudate catalyst and n-heptane and nitrogen in 12.70 and 15.24 cm diameter Lucite tubes at 0-25.9 cm/sec gas velocity and 0.86-9.40 cm/sec liquid velocity. The catalyst bed contracted measurably on gas injection for the smallest (0.0635 cm dia) catalyst but not at all for the largest (0.1600 cm dia) catalyst. Correlations were developed for the effect of gas velocity on bed expansion, based on particle Reynolds numbers, sphericity of the particle, and the liquid-to-gas velocity ratio. For a given catalyst, a chart is readily prepared for catalyst expansion as a function of liquid and gas velocities. Three-phase fluidization is used in hydrodesulfurization processes such as H-Oil and H-Coal. Graphs and table.