Heat-conducting composite pipes could make desalination less costly
By Ben Coxworth
October 8, 2012
In a typical desalination plant, pipes made from titanium or other expensive types of metal are an integral part of the process. Now, however, scientists have created a new type of piping material that is much cheaper to produce – potentially making desalination possible in countries that previously couldn’t afford it.
Ordinarily, hot water or gas is pumped through pipes composed of titanium or a high-alloy steel. That piping conducts heat from the water or gas, which is transferred to its outer surface, causing it to become hot. When seawater is then sprayed onto the outside of that hot pipe, its pure water content evaporates and is collected, while its salt content forms into a sludge on the pipe.
In an effort to come up with a less costly heat-conductive piping material, researchers from Germany’s Fraunhofer Institute for Manufacturing Technology and Advanced Materials combined a polymer with copper microfibers – the mix is as much as 50 percent copper, by volume. The resulting composite can reportedly still be processed like regular plastic, yet it conducts heat like metal.
Pipes made from the material are now being tested in a desalination plant, where gas heated to 70ºC (158ºF) is continuously being pumped through them. The scientists plan on assessing the material’s thermal conductivity along with its corrosion resistance, then tweaking the mixture as needed.