Bubble column reactors are quite popular in the chemical, biochemical and petrochemical industries due to their relative simple construction; favorable heat/mass transfer properties and low operating cost. Although the hydrodynamics of small size columns is relatively well understood, the knowledge of industrial scale bubble columns is still rather rudimentary. In this research work, hydrodynamics of a 45 cm diameter bubble column has been investigated using ‘Four- Point Optical Probe’ technique. Analysis of overall gas holdup and local bubble properties at a fully developed axial position was conducted for range of superficial gas velocity covering both bubbly and churn-turbulent regimes.
Analysis of overall gas holdup has depicted an increasing behaviour with increase in superficial gas velocity, which was similar to that reported in the literature. A transition from bubbly to churn-turbulent regime was noticed at Ug ≥ 10 cm/s. An increase in overall gas holdup from 8 - 34 % was obtained for the operating range of gas velocity. Radial profiles of bubble properties have shown an increasing behaviour with increase in Ug. These profiles were relatively flat in the bubbly regime. With increase in Ug an increasing trend in parabolic pattern of the plot was evident in all cases. Similarities among radial profiles have demonstrated a strong correlation in bubble properties. In summary, the bubble properties obtained in present study can give a deeper understanding of the hydrodynamics in large size bubble columns which can be useful in scale-up investigations.