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International Society for Industrial Process Tomography

11th World Congress on Industrial Process Tomography

Characterization of Gas Dispersion Effectiveness in a Coaxial Mixer Containing a Yield-Pseudoplastic Fluid using Electrical Resistance Tomography

P. L. Barros1*, F. Ein-Mozaffari1, A. Lohi1

1Department of Chemical Engineering, Toronto Metropolitan University, Toronto, Canada

*Email: paloma.barros@torontomu.ca


ABSTRACT


The characterization of gas-liquid mixing systems containing non-Newtonian fluids has been extensively investigated due to their broad industrial applicability. Evaluating the effectiveness of gas dispersion often relies on parameters such as gas holdup. Among the various measurement techniques available, the electrical resistance tomography (ERT) offers notable advantages, particularly its non-invasive nature, which enables accurate calculation of gas holdup based on conductivity measurements. This study aims to employ ERT to determine the local and global gas holdup values in a coaxial mixer used for dispersing air into a yield-pseudoplastic xanthan gum solution. The coaxial mixer consisted of a co-rotating anchor and an upward-pumping pitched blade turbine. The effect of rotational speeds of the anchor and central impeller on gas dispersion was investigated at different aeration rates, and the results revealed no clear trend in the impact of agitation on the global gas holdup. However, the analysis of local gas holdup clearly demonstrated that increasing the anchor speed enhanced gas dispersion uniformity within the mixing vessel. This finding was further supported by calculating the relative standard deviation of local gas holdup values, which indicated higher gas dispersion homogeneity at the highest anchor speed. Overall, ERT measurements enabled characterization of the local gas holdup distribution that provides valuable insights into gas dispersion homogeneity and can significantly contribute to the design improvement of complex mixing systems across various industrial applications.

Keywords: Electrical resistance tomography, Gas-liquid mixing, Gas holdup, Coaxial mixer, Non-Newtonian fluids

Industrial Application: General

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