Case Study: Johnson Matthey Radial Flow CFD Validation

Background and Objectives:

Achieving an even flow distribution in large packed bed reactors is critical to their performance.
Johnson Matthey Catalysts needed to directly measure the flow distribution of a fluid through such a reactor.
Process Tomography offers the opportunity to visualise the contents of vessels and pipelines without disturbing the flow.
An ITS p2000 8-channel Electrical Resistance Tomography system was used for data acquisition.

Results:

Results from a single measurement plane near the centre of the bed height are shown below.

Figure 1: Tomographic images from one measurement plane after addition of
high conductivity tracer

A colour scale is used to show variations in conductivity with blue representing the conductivity of the main fluid (water) and red indicating the high conductivity tracer.
The images clearly show the build up of the tracer near the reactor walls, then the front moves towards the centre and the tracer is distributed throughout the reactor cross-section. The trailing edge of the tracer detaches from the wall and moves towards the axial exit zone.
ERT technology has been successfully applied to a large scale physical model of a radial flow reactor to demonstrate that the desired flow pattern was being achieved.

Benefits:

The experimentally derived velocity map agreed qualitatively well with the CFD results, thus going a long way to validating the CFD model and providing Johnson Matthey with the confidence to explore alternative reactor designs.
Using Tomography on a large scale physical model of a radial flow reactor saved Johnson Matthey a great deal of money validating the CFD model and it was achieved in a much shorter time.