Can polymer replace titanium in thermal desalination?
Researchers from the Fraunhofer Institute for Manufacturing Technology & Advanced Materials in Bremen, Germany, have developed a heat-conducting polymer composite tube which they believe will soon be replacing titanium in thermal desalination plants.The material was introduced at the Composites trade fair in Düsseldorf (9‑11 October 2012).
"We introduced metal particles into the material - or more precisely, we add up to 50% copper microfibers by volume. This does not change the processing properties of the composite, and it can still be processed as any other polymer would," notes Arne Haberkorn, a scientist at IFAM.
The researchers have already developed the material itself; now they want to optimize its thermal conductivity. To accomplish this, they are installing the piping in a pilot seawater- desalination plant to test its thermal conductivity and check to see how much of a microorganism-based coating forms on the pipes and how heavily the material corrodes in its salty surroundings.
They will then optimize the composite properties based on the results. The researchers have set the evaporation process to run at a temperature of 70ºC - so there is hot gas heated to 70ºC pumped through the pipelines. This offers several advantages: fewer deposits congregate on the pipes, the material does not corrode as quickly, and the pressure differential between the inside and outside of the piping is not as dramatic.