Australian Scientists have developed a new generation heat exchanger (RAMeX) which offers lower energy costs, a smaller industrial footprint and more efficient heat transfer and mixing.

The new heat exchange technology is based on CSIRO’s RAM Mixer technology developed by CSIRO Manufacturing & Materials Technology fluid dynamics laboratories based in Melbourne.

The RAMeX offers a new method of mixing and heat exchange for highly viscous fluids without the need for the current methods of using stirrers, impellers and plates.

There are a range of industrial applications suited to the RAMeX where a low shear and a high performance homogenizing mixer and heat exchanger offer advantages. These include the diary industry, cosmetics manufacturing, sugar making and the more efficient mixing of explosives compounds where poor mixing often leads to poor performance.

A RAMeX bio-reactor can also be used for mixing viscous cell cultures with nutrients and oxygen. Candidate bio-products include astaxathin (an aquaculture food additive) and xanthan gum (a common thickening and emulsion additive in food products, and for oil drilling muds) which have intrinsically large processing viscosities.

The chaotic mixing produced in the RAMeX creates very fine-scale structures within a polymer melt ideal for difficult new applications such as electrically conducting polymers.

The developers of the RAMeX, Dr Guy Metcalfe and Dr Murray Rudman said before building the original RAM Mixer, the concept was developed mathematically. They said the prototype proved its potential to revolutionise traditional mixing technology.

“After this, enthusiastic responses from potential users provided us feedback which has led to the development of the CSIRO RAMeX,” Dr Metcalfe said.

Like the earlier RAM technology, development of the RAMeX relied on the use of advanced mathematics and simulation technology to fast track the development of an operational RAMeX.

“Trials have shown the RAMeX now provides a single solution to the task of mixing and temperature control in highly viscous fluids, used for example in food processing, polymer processing and in the mixing of explosives,” Dr Metcalfe said

Laboratory trials of the CSIRO RAMeX have shown it produces homogenous heating or cooling through a smaller heat exchange unit at a faster rate than can be matched by typical mixers using shell-in- tube (jackets) or annular (tube-in-tube) heat exchangers.

The CSIRO RAMeX offers plant with a smaller footprint and is expected to be less expensive to manufacture than most current mixers. It can be used as a batch mixer or for in-line continuous mixing.

The CSIRO RAMeX design is similar to the earlier generation tube shaped RAM mixers, allowing for the easy application of selected heating mediums such as water, or steam.

The simple design removes the need for internal baffles and plates used in static mixers that generate large pressure drops and energy use.

The development of a pilot RAMeX has built on the advantages of the earlier RAM Mixer such as:  

• mixes twice as well as an equivalent commonly used static mixer
• consumes five times less energy
• offers low shear effective mixing
• produces no stagnant regions
• is easy to clean
• has no internal surfaces (baffles, plates, etc.) to produce material build up
• easy to scale-up to plant - flow fields are the same irrespective of size
• easily handles very high viscosity fluids

The RAMeX is CSIRO patented technology now ready for commercial development.