Water-Repellent Coating

Water repellent coatings are already being used in a variety of energy-saving applications from self-cleaning buildings to more fuel-efficient ships. Now engineers have found a way to use them for reducing carbon emissions from fossil-fuel-burning power plants by improving the efficiency of steam condensers.

As fuel is burned, it produces steam which is fed into a condenser. In the condenser, it cools down and condenses back into water, creating a suction force that helps drive a turbine. Normally, there is a tendency for water to build up on the walls of the condenser pipes, which slows down the cooling process. But coating the pipes with the new water-repellent prevents that from happening and thereby increases the suction force.

The coating itself must be thick enough to withstand the high temperatures and steam, but thin enough so as not to slow down the cooling process in and of itself. A deposition process was developed whereby two gases flow past heated filaments causing a reaction that forms a polymer coating of the optimum thickness.

It has been estimated that the annual reduction in carbon emissions that would be realized by using the coating at just one coal burning power plant would be equivalent to taking as many as 4,000 cars off the road. And with 85 percent of the world’s power still coming from steam turbine power plants, the potential global impact could be significant.