Reporter 442, 8 November 1999

New centre offers perfect blend when mixing minerals, make-up and mayonnaise

Researchers in a new University centre believe they hold the key to perfect mayonnaise. Blending oils and water successfully is a tricky process. Gallons of lumpy sauces and runny sun tan cream are regularly thrown away by industry and many an amateur chef has been left with egg on their face and separated liquids in the bin. Help may be at hand, however, from the unlikeliest of sources...

See-through systems: Professor Richard Williams leads the new Centre for Particle and Colloid Engineering

"It may seem curious to be making foods and personal products in a mining and mineral engineering department," says Professor Richard Williams. "But the problems caused by emulsions go across all industries, from minerals, chemicals and pharmaceuticals to the food and drink sector."

Shake a bottle of Irish Cream and the alcohol and cream form an emulsion. Shake more bottles (wallet-allowing) and the gloopy mixture produced will be different each time. This inconsistency causes manufacturers real headaches. One batch of mayonnaise, paint or china clay can be very different from the next. As a result, entire lorry-loads of expensive creams and lotions never reach the shelves.

"Consumers want a product to feel the same each time," said Professor Williams. "Sun tan cream that seems too runny is probably just as effective against UV light but people don't like it because it feels funny. So it gets thrown away before it even reaches them."

Professor Williams is leading University research developing a novel way of producing these awkward mixtures. By pouring one liquid through a ceramic tube and squeezing a second through holes in the tube walls, the two can be mixed with more control, yielding more consistent results.

The team, in the new Centre for Particle and Colloid Engineering, has had great success using the technique to combine liquids, and solids and liquids, on a laboratory scale. The next stage is to scale up the technology to the monster-sized vats and reactors used by food, drink and chemical companies. Understanding how liquids flow inside these giant reactors is crucial to blending them consistently.

To this end researchers have developed state-of-the-art technology allowing them to ‘see’ inside pipes and tanks. Passing an electrical current across the flowing liquid means the locations of gases and solids can be picked out on a computer screen. Dozens of images a second can be taken across a ‘slice’ of the reactor, building up a reliable picture of what is happening within. Professor Williams is developing this ‘process tomography’ technique with Professor Brian Hoyle in electrical engineering and colleagues at UMIST.

The imaging technology also has important potential in developing safer chemical reactors. More accurate mapping of explosive gases such as hydrogen inside the vessels shows where problems are likely to occur, meaning better safeguards can be built into systems.

The Centre for Particle and Colloid Engineering’s official opening is on November 18 and Professor Williams is delivering his inaugural lecture Shake Rock and Roll on the same day. Professor Williams and Professor Hoyle are running a one-day workshop on the process tomography technology at Weetwood Hall on November 24. More

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