Demonstration of a Novel Retrofit Tomography Baffle Cage for Gas-Liquid Mixing Studies Under Intense Operating Conditions

M. Cooke1, G. Bolton2, D. H. Jones3 and D. Housley4

1Dept. of Chemical Engineering, UMIST, PO Box 88, Manchester, M80 1QD, UK E-mail: michael.cooke@umist.ac.uk

2 Industrial Tomography Systems, 47 Newton Street, Manchester, M1 1FT, UK E-mail: gary.bolton@itoms.com

3Huntsman Polyurethanes, Everslaan 45, 3078 Everburg, Belgium E-mail: don_h_jones@huntsman.com

4DuPont (UK) Limited, DuPont Polyester Technologies, PO Box 2002,

Wilton, Middlesborough, TS90 8JF, E-mail: duncan.housley@gbr.dupont.com

ABSTRACT

An existing stirred tank facility was modified in order to demonstrate that an 8 plane by 16 electrode ERT could be successfully applied to the study of gas-liquid reactors operated at intense conditions. Mechanical agitation was by dual T/2 diameter impellers operated at energy dissipation rates ([JT) of up

to ~ 10 kW/m3 liquid and superficial gas velocities of up to 0.1m/s. Gas hold-ups were up to 50% by

the addition of surfactant.

Because of the design of an existing 0.61m-model vessel the tomography set-up required to be an add-on unit that fitted inside the vessel with minimum interference with flow visualisation and with no interference to analysis ports and existing instrumentation. To facilitate this end, the tomography sensors were designed to form an integral part of a specially designed baffle cage. Some commissioning problems caused by the large size of the metal agitators and the metal support rings were solved by replacing the metal rings with plastic and by powder coating the agitators. The unit was then successfully demonstrated and these results are presented.

Keywords Stirred vessel, gas-liquid, intense operating conditions, tomography.