Predictions of radial gas holdup profiles in bubble column reactors

Gas holdup and its profile are important parameters to be characterized in bubble column reactors. Proper prediction of the radial gas holdup profiles is necessary for determining liquid mixing, flow regime transition, heat a nd mass transfer. In this study, the following gas holdup profile form, whi ch can be fitted to the observed holdup profiles, is proposed: epsilon (G) = <(<epsilon>)over bar>(G)(n + 2/n + 2 - 2c)[1 - c(r/R)(n)]. The parameters n and c needed to describe the gas holdup profile are correl ated with appropriate dimensionless groups. n = 2.188 x 10(3) Re-G(-0.598) Fr-g(0.146) Mo-L(-0.004), c = 4.32 x 10(-2) Re-G(0.2492). However, the cross-sectional average gas holdup, <(<epsilon>)over bar>(G), can be estimated using the available correlations for overall gas holdup. T he agreement between the correlation predictions and experimental data is r easonable over wide range of operating conditions. (C) 2001 Elsevier Scienc e Ltd. All rights reserved.