EFFECT OF HEIGHT OF PACKED-BED IN DOWNCOMER ON LIQUID-MIXING TIME IN BUBBLE-COLUMN WITH DRAFT TUBE

The effects of the height of packed bed in a downcomer on the liquid m ixing time in a bubble column with a draft tube are experimentally inv estigated, while varying gas flow rate and packed bed height under con ditions of two types of gas dispersion; gas dispersed into the inner s ection of the draft tube, and into the annular section between the col umn and the draft tube. In either type of gas dispersion, the liquid m ixing time in the presence of the packed bed increases with increasing superficial gas velocity and decreases with increasing packed bed hei ght. It shows that the degree of increase in liquid mixing times is pr oportional to the superficial gas velocity raised to the power of 1/3 and the packed bed height raised to the power of 1/4, regardless of th e type of gas dispersion.