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quarta-feira, 25 de abril de 2012

Nanoparticle Could Recapture Water Lost at Power Plants

I have covered the role that nanotechnology can play in providing clean drinking water numerous times in this blog over the years, going as far back as 2007 and as recently as February this year.  But over the years the various nanotechnologies I have covered have been related to desalination processes--like those I linked to above--or improved filters to provide clean drinking water in remote regions of the world.
The latest nano-related development for water comes from Argonne National Laboratory. It is completely different from what I have seen before and addresses a huge issue: water waste at nuclear- and coal-powered power plants.
Approximately 40 percent of the US’s freshwater withdrawals and 3 percent of overall freshwater consumption goes to simply feeding the steam generators at power plants. Because the power plants use partially condensed high-temperature steam to run the turbines, a significant amount of water is lost due to evaporation and cannot be recaptured.
The technology the Argonne researchers are developing to address this issue and reduce the amount of fresh water lost is a nanoparticle based on a “core-shell” configuration, which basically means that the nanoparticles have a core made of one type of material and the coating of that core is another type of material. In this case, the outer coating protects an inner core that melts above a certain temperature.
The nanoparticles are dispersed in the plant’s water supply so that they absorb heat during the thermal cycle of the process. This causes the nanoparticles to melt partially, but they totally solidify again once they reach the cooling tower. Apparently, water is conserved because the outer coating bonds with the water molecules.
This is very preliminary research and they are still experimenting with the chemistry at the boundary between the metal nanoparticles and the water molecules. But it is such a large issue that the project looks like it’s getting fast-tracked. There are plans to have a proof of concept this year and a full-scale commercial deployment in four years.
“It’s practically unheard of for industry to seek to deploy a new technology so quickly,” said Argonne associate division director Thomas Ewing. “However, water consumption is a major issue that limits the expansion of power. If we want to solve the energy crisis, we’ll have to move boldly.”
Fonte: NanoClast