The Use of Positron Emission Particle Tracking in the Study of Multiphase Stirred Tank Reactor Hydrodynamics

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 agitated with a Rushton turbine and an upward‐pumping pitched blade turbine. PEPT captures the full three‐dimensional characteristics of hydrodynamics and mixing in stirred vessels, 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 facilitates the evaluation of impeller design, particularly with the aim of minimizing mass transfer limitations.

Particle flow in a hydrocyclone investigated by positron emission particle tracking

“…Ding et al, 2002;Ingram et al, 2005;Parker et al, 1997) and stirred vessels (e.g. Barigou et al, 2009;Fishwick et al, 2005a), flows generated by turbines (Fishwick et al, 2005b;Pianko-Oprych et al, 2009), paste flows (Wildman et al, 1999), inclusion movements in castings (Griffiths et al, 2008(Griffiths et al, , 2010, and other processes.…”

“…The 3-D particles trajectories in mixing process in a powder, a biscuit crumble and a liquid slurry have been obtained. Since then PEPT has been applied to investigate the flow in a variety of equipment and processes, including rotating drums [43][44][45], various type of mixers [46][47][48][49][50][51], fluidized beds for various purposes [52][53][54], extrusion systems [55], stirred grinding mills [56], stirred vessels [57,58], the pharmaceutical Wurster coating system [59], rolling foodstuff cans [60], multiphase stirred tank reactors [61], casting [62][63][64], pipes [65,66], valves [67] and twin screw granulators [68].…”

The use of positron emission particle tracking as a method for tracking particles in flotation froths

“…This understanding would be able to enhance and validate mathematical models that predict the motion, and therefore the performance of such systems. Previous work using PEPT has tracked the motion of particles in stirred vessels [4][5][6][7], granulators [8], fluidised beds [9], and initial work on following mineral particles in froth flotation cells [10]. Froth flotation is a process by which valuable mineral particles are separated from gangue through the differences between the hydrophobicity of different minerals.…”

Evaluation of large Eddy simulation and Euler‐Euler CFD models for solids flow dynamics in a stirred tank reactor

“…Also, such optical method is likely to fail in case of dense suspensions where the system tends to become more and more opaque. Recently, Fishwick et al29 used the positron emission particle tracking (PEPT) to study the hydrodynamics in solid–liquid stirred tanks. They successfully demonstrated that PEPT can provide Lagrangian description of solids hydrodynamics in the reactor, but their study is limited to a very dilute system as well (1% w/w).…”