Flow Regime Characterization in Bubble Column Equipped with Internals

Abstract

This paper looks into how a bubble column's flow regime is affected by sparger geometry and with the presence of an internal occupied 25% of the cross-sectional area. The flow pattern essentially describes the flow structure or distribution of one fluid phase relative to the other. The new technique used three differential pressure transducers (TM-Sensor) connected to a data acquisition card to detect the pressure fluctuation and measure the total gas hold-up. The experiments were conducted in a cylindrical Plexiglas® column with a 13- cm internal diameter and 183 cm height under atmospheric pressure with a two-phase system of liquid/air. Two types of perforated plate spargers were used, with the hole diameter ranging from 1-2 mm. The data compared to the literature on the experimental transition gas holdup values and predictions made by linear stability theory. Correlations were based on dimensionless numbers (Archimedes, Froude, and Weber) and the group (do/DC) to predict gas holdup in a homogeneous regime. The correlation predictions and experimental values had an average inaccuracy of less than 20 %. The published data were compared to the proposed correlation, which is in rather good agreement. Internals were found to have an impact on the overall gas holdup. Still, they significantly altered the structure of the gas holdup, with a small bubble holdup increase and a large bubble holdup decrease in the transitional and churn-turbulent regimes, respectively.