환상기포탑에서의 기체체류량 및 액체의 축방향혼합특성 = Gas Hold-up and Axial Mixing Characteristics of Liquid in an Annular Bubble Column

다국어 초록 (Multilingual Abstract)

Gas hold-up and axial mixing characteristics of liquid were investigated in an annular bubble column with a gas-liquid simultaneous injection nozzle as a gas distributor. Gas hold-up was measured by manometric method and longitudinal dispersion coefficient of liquid phase was determined by longitudinal tracer concentration distribution at steady-state and residence time distribution.
For the lower liquid velocity, experimental results showed that gas hold-up increased with increasing gas and liquid velocity, and it decreased with increasing diameter of inner tube. For the higher liquid velocity, however, small bubbles were uniformly dispersed and gas hold-up was not affected by liquid velocity and size of inner tube.
Also, the mixing characteristics of liquid was identical in all section of column under the experimental conditions, and longitudinal dispersion coefficient of liquid phase decreased with increasing liquid velocity. Furthermore, the effects of gas velocity on longitudinal dispersion coefficient for higher liquid velocity was larger than that for lower liquid velocity. And, longitudinal dispersion coefficient increased with increasing diameter of inner tube for transition flow regime, by contrast, it was not affected by diameter of inner tube and liquid velocity for higher liquid velocity.
For given gas and liquid velocity, the annular bubble column gave significantly higher gas hold-up and extent of axial liquid mixing than a cylindrical column of equivalent crossectional area, because of wall effect of concentrically located inner tube.