On Reconciling Tomographic Measurements with a Fluid Mixing Model for Semi-Batch Operation of a Stirred Vessel

S J Stanley1, H V Hristov1, R Mann1 and K Primrose2

1 Department of Chemical Engineering, UMIST, PO Box 88, Manchester, M60 1QD, UK, r.mann@umist.ac.uk

2 Industrial Tomography Systems Ltd, 47 Newton Street, Manchester, M1 1FT

ABSTRACT

A newly assembled 16 electrode 8 plane ERT system retrofitted to a plant scale 2.3 m3 vessel has been used to image the vessel volume for single feed semi-batch operation. Images reconstructed from the raw ERT measurements are represented as time incremented three-dimensional solid-body colour-scaled isosurfaces providing a five dimensional representation of the fluid mixing. The tomographic measurements have been evaluated against a network of zones (NoZ) model, which is able to compute the time evolving three-dimensional concentration fields during the semi-batch feed addition. Mixing curves generated from the semi-batch NoZ model have been compared to those reconstructed from the ERT system. Like the ERT system, the NoZ model is also able to visualise the detailed structure of the evolving feed plume. It also has the power to image and independently predict the corresponding time-wise reaction behaviour in space for a simple A+B → products reaction.

Keywords Stirred vessel, fluid mixing, electrical resistance tomography, semi-batch