(84f) Bubble Size DistributionsBsd for a Bubble Column Reactor Undergoing Forced Oscillations

Previously(1,2,3) it has been shown that low amplitude (0.5 mm? 2.5 mm) oscillations at moderate frequencies ( 0 ? 25 Hz) can be used to improve the bubble column performance. Here, we report the study of bubble size distribution (BSD) in an oscillating bubble column reactor for air ? water system. A high speed digital camera was used to measure BSD at different heights in the column. Effects of various operating parameters such as frequency, amplitude and gas flow rate were studied. Sauter mean diameter was calculated from BSD data and it was correlated as a function of power input per unit mass using Hinze formulation. Population balance modeling simulations were performed based on Least Squares method(4). The predictions obtained from the simulation for the bubble size distribution and the Sauter mean diameter at different power input is in agreement with the experimental observations.

1.Knopf FC, Ma J, Rice RG, Nikitopoulos D. Pulsing to improve bubble column performance: I Low gas rates. AIChE J. 2006;52:1103-1115.

2.Knopf FC, Waghmare Y, Ma J, Rice RG. Pulsing to improve bubble column performance: II Jetting gas rates. AIChE J. 2006;52:1116-1126.

3.Waghmare YG, Knopf FC, Rice RG. A new theory to explain transport in pulsed-flow bubble columns: the Bjerknes effect. AIChE J. 2007; accepted for publication.

4.Dorao CA, Jakobsen HA. A least squares method for the solution of population balance problems. Computers & Chemical Engineering. 2006;30:535-547.