Hydrodynamics and mass transfer in a draft tube airlift reactor with dilute alcohol solutions



The aim of this work was to investigate an influence of different alcohols on the behavior of a draft tube airlift reactor. The main hydrodynamic and mass transfer parameters in 1 wt % aqueous solutions of five aliphatic alcohols were examined. The results showed that alcohol addition enhanced gas holdup and mass transfer coefficient, but led to notable reduction of liquid velocity and hence elongation of circulation time, relative to the values determined for water. By introducing the surface tension gradient as a relevant independent variable, we defined a simple empirical correlation for overall gas holdup, circulation time, and mass transfer coefficient. The proposed empirical correlations have shown a satisfactory agreement between the calculated and the experimental data. © 2007 American Institute of Chemical Engineers AIChE J, 2007