EFFECT OF STATIC LIQUID HEIGHT ON GAS-LIQUID MASS TRANSFER IN A DRAFT-TUBE BUBBLE COLUMN AND THREE-PHASE FLUIDIZED BED
Titel:
EFFECT OF STATIC LIQUID HEIGHT ON GAS-LIQUID MASS TRANSFER IN A DRAFT-TUBE BUBBLE COLUMN AND THREE-PHASE FLUIDIZED BED
Auteur:
Bavarian, Farshad Linn, Chia-Jui Ramesh, T. S. Fan, Liang-Shih
Verschenen in:
Chemical engineering communications
Paginering:
Jaargang 108 (1991) nr. 1 pagina's 347-364
Jaar:
1991
Inhoud:
Experiments are performed under batch-liquid operating conditions to investigate the effect of static liquid height on the gas-liquid mass transfer coefficient (KLa) in a draft-tube bubble column (DTBC) and a draft-tube three-phase fluidized bed (DTFB). In addition, the effects of column diameter, gas-distributor, and draft-tube diameter are studied. The results indicate that for a given system with a porous plate gas-distributor at low superficial gas velocities (<70 m/hr), increasing static liquid height decreases KLa. At high gas velocities, KLa is independent of the static liquid height. For systems with a perforated gas-distributor, there is no effect of static liquid height on KLa. The formation of small dispersed bubbles at low gas velocities in the porous plate distributor system accounts for the considerably high KLa values and the observed effect of liquid height. On the other hand, the formation of large spherical-cap bubbles and the bubble coalescence at high gas velocities reduce the performance of the porous plate distributor system to that of the perforated one.