Corrosion in a steam boiler

Chemical Company, Cairo Egypt


The Problem

In the chemical industry significant amounts of steam are needed for different processes. This client uses several boilers, with a total capacity of more then 100m3 per hour. The feed water is treated chemically. The demineralised water becomes aggressive and together with the high temperatures inside the boiler corrosion starts at all surfaces in contact with the water.

The client regularly added inhibitors to prevent corrosion. Study shows that even by using chemicals, corrosion still occurs. Iron or rust in the steam will cause further corrosion in the pipe systems and this leads to a shorter lifespan of eqiupment.

The Solution

A Merus ring was installed at the feed pipe of the boiler. In the first weeks there no change in the use of inhibitors against corrosion

The Result

The iron content in the steam and the Blow down pipe was regularly checked. The iron in the steam became less and less, and finally stabilized on a very low level.

Adding inhibitors didn't stop until 6 weeks after installation. This was also the regular production break where service is carried out on the boiler. On visual recorded inspection, it was seen, that most of the surface was now black, coated with saturated iron oxide, only a few red spots of red rust was observed, and it was expected these would disappear too.

After witnessing this result the client decided to stop adding corrosion inhibitors. The steam is still regularly checked for iron.

  1. No more chemical dosing.
  2. No more chemical cleaning costs
  3. No mechanical cleaning costs.
  4. Corrosin has stopped, no more rust or scale
  5. Internal surfaces protected by black oxide.

It is assumed that the lifespan of the system has now also increased dramatically.


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