Electrical Impedance Tomography (EIT) Imaging of Solid-liquid Suspensions using Vertically Deployable Sensor Electrode Arrays

S. C. Murphy1, S. J. Stanley2, D. Rhodes3 and T. A. York1

1School of Electrical Engineering, The University of Manchester, UK.

2Nexia Solutions, Hinton House, Risley, Warrington, UK, Email: sjs20@nexiasolutions.com

3Nexia Solutions, B170 Technology Centre, Sellafield, Seascale, Cumbria, UK.

ABSTRACT

The paper describes the use of Electrical Impedance Tomography (EIT) for imaging solid-liquid suspensions. For applications involving solids handling, solid suspensions and the movement of solid liquid mixtures, EIT offers a means to infer otherwise unobtainable spatially and temporally varying process information. The present work is targeted at the nuclear industry and a sludge stimulant has been supplied by Nexia Solutions Ltd. To ease deployment electrode arrays are attached to the inside wall of the test vessel as vertical strips of flexible printed circuit board. The Manchester LCT instrument has been used to acquire data with a strategy that, for 3 vertical strips comprising 8 electrodes each, delivers 348 measurements for each frame. 3D images are reconstructed using a linear Newton-Raphson difference algorithm incorporating Tikhonov regularisation. Conductivity profiles are determined from the reconstructed images and these reveal different trends across the volume of the vessel. This information could be used to determine different states of suspension.

Keywords: electrical impedance tomography, linear array, solid liquid suspensions.