Study of Stirred Tank Reactor Hydrodynamics Using Positron Emission Particle Tracking

R P Fishwick1, E H Stitt2 and J M Winterbottom1

1Chemical and Formulation Engineering, The University of Birmingham, Edgbaston, Birmingham B15 2TT, UK. email: J.M.Winterbottom@bham.ac.uk

2Johnson Matthey Catalysts, PO Box 1, Belasis Avenue, Billingham, Cleveland TS23 1LB, UK.

ABSTRACT

This paper describes the use of Positron Emission Particle Tracking (PEPT) in the analysis of local particle and fluid velocities in solid-liquid stirred tank reactors. PEPT captures the full three- dimensional characteristics of stirred tank reactor hydrodynamics and mixing, allowing the analysis of the two-phase flow fields. Furthermore, by comparing the liquid and particle velocities, the spatial and temporal variation of the relative particle-liquid velocity can be estimated. Such information reveals considerable heterogeneity in the vessel and allows the evaluation of impeller design with the aim of minimising mass transfer limitations. The variation in slip velocity also serves to identify some of the problems associated with stirred reactor design, particularly when scaling-up a process.

Keywords Particle Tracking, Fluid Trajectory, Stirred Vessel, Slip Velocity.