Holdup of Gas Bubbles in Fluid Beds

Abstract

The radial distribution of holdup of gas bubbles was measured in fluid beds with diameter of 6.6, 12 and 19 cm by use of a small hot-wire probe. The radial distributions of holdup of gas bubbles are almost the same in the region of bed height where the effect of the distributor is considered to be negligible. The holdup of gas bubbles, εb, at radial distance γ from the center axis of the tower is expressed as
(εbc-εb/εbc) = (εbc-εbw/εbc) (γ/R) ⁿ
where
εbc is holdup of gas bubbles at the center axis of the tower
εbw is holdup of gas bubbles extrapolated to the tower wall and R is radius of fluid bed.
Furthermore, the relationships among (εbc-εbw) /εbc or n and the gas velocity and tower diameter were obtained.