Diagnosis of bubble distribution and mass transfer in pressurized bubble columns with viscous liquid medium

Abstract

Bubble distribution and its effects on the gas–liquid mass transfer have been investigated in a pressurized bubble column whose diameter and height are 0.152 and 2.0 m, respectively. Effects of gas velocity (0.02–0.20 m/s), pressure (0.1–0.6 MPa), liquid viscosity (1.0–38.0 MPa s) and bubble distribution mode (even, wall-side, central and asymmetric distribution) on the volumetric gas–liquid mass transfer coefficient and bubble flow behavior have been examined. Pressure fluctuations have been measured and analyzed by adopting the deterministic chaos theory as well as spectral analysis. It has been found that the even distribution of bubbles is the best mode for mass transfer. The volumetric gas–liquid mass transfer coefficients when the bubbles are distributed in a mode of wall-side distribution have been relatively higher than those when the bubble distribution mode has been central or asymmetric. The bubble flow regime and its transition have been detected by analyzing the pressure fluctuations in the column. The gas holdup and volumetric gas–liquid mass transfer coefficients have been well correlated with the correlation dimension of pressure fluctuations elucidating the bubble distribution in the pressurized bubble columns.