Lime scale in a steam boiler

Company: SHELMAN A.E., paper industrie

Description of the problem and its negative consequences
The feeding water of the steamboiler is rather soft, so the client decided out of economical reasons, to use city water, instead of a expensive and service intensive chemical treatment. So the steam boiler had to be chemical cleaned each summer. Especially the coils have had a thick layer of lime scale. This cleaning was done chemical, which is expensive and time consuming. As well each chemical cleaning harms the inner surfaces of the machine, which leads to additional corrosion an the risc of leakage.
A few month after the chemical cleaning, the performance of the steamboiler start to drop. So it took more and more time until there was enough steam to start production, and as well the amount of steam produced per hour decreased steadily. At the same time the energy used to produce the steam increased, because of the isolation effects of the limescale. By the way just one mm of lime scale reduces the performance by 11%.

Our solution
Approximatelly three month after the last chemical cleaning, one Merus®-Ring was installed at the feedingpipe of the steam boiler. At this time the performance of the boiler already started to drop, with the above described effects.

In which way the customer checked the results of the trial
1. In the beginning it could be seen at the blowdown pipe, that the water contained small particles of lime scale. This particles get less with the ongoing cleaning of the boiler during the normal operation.
2. The performance of the steamboiler raised again. Not only the total amount of steam was increased again, but as well the start time in the morning until enough steam was ready shortened.
3. At the next inspection of the boiler in the following summer, it could be seen, inside the boiler was no lime scale at all. As well the lime scale which has build up before the installation couldn't be found. This was the first time since start of operation, that there was no chemical cleaning necessary .