To study the effects of solid holdup on the characteristics of bubble behavior in an ebullated-bed reactor
dynamic gas disengagement was used in a plexiglas column of 7.0 m in height and 0.3 m in diameter under the condition of solid concentration from 9.8% (vol) to 39.0% (vol) by the total liquid and solid volume in the superficial gas velocity of 2.16-21.62 cm/s. The total gas holdup
bubble rise velocities
fractions and diameters of large and small bubbles were measured separately. The results show that the total gas holdup increases with the increase of superficial gas velocity
and decreases with the increase of solid holdup. With the increase of superficial gas velocity
the fraction
rising velocity
and diameter of large bubbles all increase. While for small bubbles
only their holdup increases obviously
but their rising velocity and diameter tend to decrease. With the increase of solid holdup
the rising velocity and diameter of large bubbles increase remarkably
but their holdup decreases slightly. When the solid content exceeds 19.5%(vol)
the rising rate of small bubbles decreases to almost zero. When the solid content reaches 29.3%(vol)