Developing Correlations for Prediction of Hydrodynamic Parameters in Bubble Column Reactors Operating with Non-Newtonian Liquids

Developing
a model for prediction of bubble size in bubble column reactors operating with
non-Newtonian liquids

Amin Esmaeili K.S., Jamal Chaouki,
Christophe Guy

Department
of Chemical Engineering, École Polytechnique
de Montréal, C.P. 6079, Succ. C. V., Montreal, QC,
Canada H3C 3A7

Tel. +1
514-340-4034, e-mail: jamal.chaouki@polymtl.ca, fax:
+1 514-340-4159

Abstract

Processes based on the contact between gas and liquid
phases and thus bubble column reactors are essential for a variety of
applications. Although there has been a growing interest in using non-Newtonian
and rheologically complex fluids in bubble column reactors,
knowledge about the effects of different rheological aspects of non-Newtonian
fluids on the hydrodynamics and specifically bubble size in such reactors is
limited. In this study, the effects of liquid phase rheology on the bubble size
in a pilot scale bubble column reactor is experimentally investigated by
applying various types of test liquids with different rheological characters as
the operating fluids. Several pressure transducers and two optical fiber probes
are used to measure the hydrodynamic parameters and the axial and radial
distribution of bubble size in the column. A schematic of the experimental
setup has been shown in figure 1. Finally, by applying the dimensional analysis
approach, a new model in the form of dimensionless numbers (Equation 1) has
been developed by introducing the dynamic moduli of viscoelastic fluids to
predict the bubble size in bubble column reactors operating with non-Newtonian
liquids as follows:

 

(1)

As it can be seen in figure 2, the obtained results
reveal that the model can predict the bubble size in non-Newtonian liquids with
a mean absolute percentage error of %9.3. In conclusion, the proposed model in
this study is very satisfactory to predict the bubble size in both highly
viscous and non-Newtonian liquids with a wide range of viscosity and
elasticity.     

Figure 1. Schematic of the experimental setup used in this study.

Figure 2. Comparison between the bubble size measured experimentally and predicted by the model.