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[Michaelangelica]

Saturday, April 21, 2007
NIOT's OTEC-based Desalination Plant

Chennai-based National Institute of Ocean Technology (NIOT) has achieved a world's first in sustainable technology by building a floating water desalination plant. But what's so great about putting a desalination plant on a barge? The uniqueness is in the detail of the technology used.

The Technology

"The plant is mounted on a 65-metre-long by 16-metre-thick barge. The ocean's surface water is boiled inside a vacuum container. The vapour created in the flash boil process is condensed through a refrigeration process with the help of deep-sea water collected from nearly 600 metres below the surface of the sea."

Thus this plant benefits from NIOT's cutting edge research and plans on OTEC, a fledgling clean energy technology which has huge potential. OTEC (Ocean Thermal Energy Conversion) is a method to use the energy difference between the surface of the ocean, which is exposed to the sun, and the water at lower levels, which not being exposed to the sun is much cooler.

The temperature of the water 600m below the surface was one third of the temperature at the surface, but bringing it to the surface presented the biggest challenge of the project. The water was brought up using one meter thick HDPE pipes, which come in 12m lengths, and when assembled the 600m stretch weighed 100 tonnes. Further the salinity of the seawater would make the pipes float, necessitating the attachment of heavy weights. The salinity however is useful in another way - the clean water is filled into water bags each capable of holding 200,000 liters, which were then easily towed to the shore since clean water floats on saline water.

The Indic View: NIOT's OTEC-based Desalination Plant - India Energy and Infrastructure

New Chinese solar de-salinator
But our device makes use of solar power. The only costs are the heliostat system and the infrastructure construction. It is the most economical and eco-friendly desalination method invented so far," said Zhou.

Furthermore, a special heliostat, invented by a scientist in the team, costs only a quarter of the normal price but still generates the same amount of energy, Zhou told China Daily.

Zhou did not reveal the exact cost for fresh water production, but said it would definitely be much lower than the current technologies,

Device offers end to fresh water shortage

desalination plant by environmental graffiti, a uk based environmental blog

The French utility services group Veolia has won a contract worth 702 million euros (945 million dollars) to design and build a water desalination plant in Saudi Arabia. The plant is expected to be completed by 2010 and will desalinate 800,000 cubic meters of water per day. Saudi Arabia already produces 24% of the total world capacity of freshwater using desalination.

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