Gas holdup and annulus liquid circulation velocity in a draft tube gas-liquid-solid spouted vessel

In a draft tube gas-liquid-solid spouted vessel, the average gas holdups an d annulus liquid circulation velocities were measured over a wide range of operating conditions, and the flow patterns were observed. The hydrodynamic characteristics obtained for the gas-liquid-solid three phase system were also compared with those for the gas-liquid two-phase system. For low gas a nd liquid flow rates, gas holdups were strongly affected by the solid parti cles, and the gas holdups in the gas-liquid-solid three -phase system were always higher than those in the gas-liquid two-phase system. Experimental e quations were also proposed to express the gas holdups in the whole range o f gas and liquid flow rates. Annulus liquid circulation velocities obtained for the low liquid flow rate were greatly reduced by the solid particle be ds on the bottom of a column. However, after all solid particles began to c irculate in the column, the behaviors of annulus circulation velocities wer e found to be very similar to those in a draft tube gas-liquid spouted vess el.