Dual-Validation of Miscible Liquid Mixing in a Stirred Vessel Imaged by Electrical Resistance Tomography (ERT)

S. J. Stanley1, E. Wabo1, R. Mann1 and K. Primrose2

1Department of Chemical Engineering, UMIST, PO Box 88, Manchester, M60 1QD, UK

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

ABSTRACT

Electrical Resistance Tomography (ERT) provides a non-invasive and non-intrusive technique to interrogate, in 3-D, the whole fluid inside a typical stirred vessel. Some ERT results are presented for a 2.3 m3 pilot scale vessel detecting the subsequent fluid mixing following the injection of a visible dye- coloured brine tracer pulse. Images reconstructed from the ERT raw data are visualised as time incremented 3-D solid body iso-surfaces, which, with the use of a colour scale to denote brine concentration, provide a 5-D representation of mixing. ‘Real’ video images of the mixing process were also captured. The way in which the tracer propagates through the vessel as captured by the ‘real’ video images has been compared and contrasted to the ERT results, in the form of two time incremented ‘real’ view contour maps. A point wise probe was also used to capture the mixing curve at a known location within the vessel. This has been compared to the mixing curve as predicted by the ERT results. With the ‘real’ video images and the point wise probe measurements, a double validation of ERT has therefore been presented, which gives a strong indication that ERT provides a reliable way to visualise mixing. This on line tomographic monitoring will offer new possibilities for control action to be linked to spatial distributions of phases and components in stirred vessels when used as chemical reactors or precipitators.

Keywords Stirred vessel, fluid mixing, electrical resistance tomography, augmented-reality