Flow Distribution and Velocity Measurement in a Radial Flow Fixed Bed Reactor Using Electrical Resistance Tomography

G T Bolton1, C W Hooper2, R Mann3 and E H Stitt2

1Industrial Tomography Systems, 47 Newton Street, Manchester, M1 1FT, UK, gary.bolton@itoms.com

2Johnson Matthey Catalysts, P.O. Box 1, Belasis Avenue, Billingham, Cleveland, TS23 1LB, UK

3Department of Chemical Engineering, UMIST, P.O. Box 88, Manchester, M60 1QD, UK

ABSTRACT

Process tomography provides for visualisation of multi-phase flows and phase distributions without disturbing the flow. Electrical resistance tomography is a relatively simple and inexpensive technique for imaging electrically conducting systems. It has been applied to visualise the flow pattern and distribution inside a radial flow packed bed of novel design for improving reactor performance with lower pressure drop. A key objective of this study was to confirm computational fluid simulation predictions. Sets of tomographic images representing slices through a packed bed have been obtained for a 8-plane x 16-electrode sensor configuration which produces of the order 103 conductivity measurements in three-dimensions. Pulse injections of high conductivity tracer, both uniformly in the feed and localised, can be imaged as multiple tomographic images, revealing the internal flow pattern. Analysis of pixels in the sensing planes and between the planes allows the local flow velocities and directions to be determined. This quantifies the flow pattern for uniformity and radial distributive properties. The density of information yielded by electrical tomography is ideal for validation of Computational Fluid Dynamics.

Keywords Packed bed, fluid mechanics, radial, flow