Nuclear core comes clean

Privatised three years ago from the Atomic Energy Authority, AEA Technology's (AEAT) business has had a complete change of heart. From being about 60 per cent nuclear in its atomic days, to around 60 per cent non-nuclear today, with a specialisation in environmental remediation, it is quite a turnaround for AEA.

`What we have done over the last three years is diversify away from our nuclear background, although a lot of what we do now stems from that background,' says Terry McCullogh, Products and Systems sales manager for AEAT.

Currently AEA Advanced Process Systems is involved in three major areas of environmental technology, all of which are in different stages of development.

The most mature area is Power Fluidics' V-tex technology which has been shortlisted for the Manufacturing Industry Achievement Awards (MIAA winners to be revealed at a ceremony on 21st September 1999).

Activity and reliability

McCullogh explains: `The history of this came from our background in the nuclear industry. We looked at building diodes, pumps, diverters and mixing systems using just fluids to do it and this is really where it all started. The nuclear industry was looking for high reliability, no maintenance [systems] because you didn't want to send your staff into highly active areas.'

The system is based on the principle of a simple vortex. It contains no shafts, no seals and there is no mechanical energy input within the body of the unit. The internal geometry is completely open with no static packings to foul, corrode or cause cavitation.

The gas enters the port tangentially and spins in a vortex and leaves by the axial port in the centre. At the same time, scrubbing liquor is sprayed into the centre of the chamber forming droplets which fly outwards against the inward bound gas.

`With the gas coming in, and the droplets going outwards we achieve a counter current flow which allows us to get a very high mass transfer within a small area giving very good scrubbing efficiency.'

For a standard single pass unit, V-tex can treat up to 20,000m3/hr in a single stage but they can be stacked.

`If you have dirty liquid that you need to strip out VOCs from, we can pump the dirty liquid in place of scrubber liquor and use clean air or steam to strip out VOCs from the liquid - the same process in reverse.'

`The added advantage of V-tex over conventional packed columns is that you can take out particulate at the same time. We can load the scrub liquor with a significant weight of particulate without actually blocking it.'

V-tex also quenches gas. Gas may be coming in at the inlet at over 400 degrees C, but it can be cooled to ambient temperature on leaving the central port.

The traditional method of treating off-gases is through packed columns. But the use of packing to remove gaseous contaminants in itself creates problems - fouled packing needs maintenance.

`This is all the bio-fouling that you get (see picture), which all has to be stripped out, sent away, cleaned, brought back, and repacked at least twice a year. With our system you don't get any of that!'