Sea water – evaporator on a ship

User: THENAMARIS INC., Shipping company in Greece

We are proud on our first application in the marine industry. Right away we were pretty successful in solving problems around seawater. Since then we could install Merus Rings on many other evaporators with the same results.

In aEvaporator on a shiplmost every ship there is an evaporator used to evaporate sea water at a low temperature under low pressure. The resulting steam is condensed and used as fresh water. The left over water is led back to the sea.

With the seawater salt and other substances from the sea enter the system. Therefore the inner surface of the heat exchanger in the evaporator gets coatet with a crust of deposits. This builds up over the time and impedes the heat transfer. Subsequently the performance diminishes day by day until the required amount of fresh water can not be produced anymore. This is the point, where fresh water needs to be bought in addition.

A traditional solution for this problem is cleaning the system chemically and manually. Both methods are very expensive and time consuming. In addition the chemicals can harm the human and environmental health. One other disadvantage is that the evaporator can’t be used during cleaning times.

Improving the performance of the evaporator with a Merus Ring

We installed two Merus Rings at each sea water inlet. Furthermore there were two Merus Rings at a chemically cleaned boiler (A) and two more at a second boiler (B) which hadn’t been cleaned for a long time. In both cases one Merus Ring would probably have been sufficient, to ensure the results we decided to play safe with two Merus Rings.

The result

In the first boiler (A) no cleaning was needed since the installation of the Merus Rings. Astonishingly the performance in the first month of the installation did not only remain stable but even increased from 28 to 31 t of fresh water in one day. The explanation for this is that chemical cleaning is not able to reach all areas of a piping system. Whereas the Merus technology can act wherever water is.

The second boiler (B) similar to (A) didn’t need further cleaning. The production volume increased very fast and reached its maximum performance soon. This means that the boiler is now fully clean and no further cleaning is necessary anymore.

Abandoning chemical cleaning is also a great benefit for the life time of the system as this can lead to heavy corrosion.