EFFECT OF FINE BUBBLES ON FLOW PROPERTIES IN BUBBLE COLUMN WITH SUSPENDED SOLID PARTICLES

JOURNAL OF CHEMICAL ENGINEERING OF JAPAN

TETSUYA MIZOGUCHI²  SHIGEHARU MOROOKA²  NOBUYUKI HIDAKA¹  YASUO KATO²  TOKIHIRO KAGO² 

[1] Department of Chemical Engineering, Kagoshima University;Department of Applied Chemistry, Kyushu University

关键词: Chemical Reactor;    Energy;    Coal;    Coal Liquefaction;    Dissolver;    Bubble Column;    Dispersion;    Mixing;    Particle;    Gas Holdup;   

DOI  :  10.1252/jcej.19.507

来源: Maruzen Company Ltd

【 摘 要 】

References(17)Cited-By(14)Flow properties in a dissolver for direct coal liquefaction were simulated by using a cold bubble column of 12 cm i.d. To generate small gas bubbles in the column, a surfactant was added to tap water and a gas distributor with fine holes was employed. When glass spheres of 44 and 113 jim dia. were suspended in the presence of the surfactant, the gas holdup was 1.5-4 times that for the tap water system, and the axial dispersion coefficient of liquid showed a minimum at superficial gas velocities of 3-5cm•s-1. The mean settling velocity of solid particles, vp, was affected by the quality of flow in addition to gas velocity and terminal velocity of solid particles. Most values of vp obtained in this experiment were larger than those for the tap water system where no fine gas bubbles were generated. Experimental equations for the correlation of vp are presented. An introduction of secondary gas in the homogeneous bubble flow regime effectively increased the axial liquid mixing. This suggests that in the design of a dissolver quenching gas injection is important to attain spontaneous discharge of ash particles from the top of the vessel.

【 授权许可】

Unknown