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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 steam boiler is rather soft, so the client decided out of economical reasons, to use city water, instead of an expensive and service intensive chemical treatment. 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 and the risk of leakage.
A few month after the chemical cleaning, the performance of the steam boiler starts 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

Approximately three months after the last chemical cleaning, one PursanovaDiskTM was installed in the feed pipe 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. These particles get less with the ongoing cleaning of the boiler during the normal operation.
2. The performance of the steam boiler 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 limescale at all. As well the lime scale which has to build up before the installation couldn't be found. This was the first time since the start of operation, that there was no chemical cleaning necessary.