Boiler cleaning

Cleaning on the water side

Unwanted deposits result in reduction in efficiency

The surface of the water side of the steam boiler must remain clean from unwanted deposits, for example salt deposits such as calcium carbonate.

Steam has the very important property of reacting at certain high temperatures with the iron ion, from the steel of the boiler wall on the water side, to a thin, uniform iron oxide (Fe3O4) film, known as magnetite.
However, the thin magnetite layer formed can age after years, become porous or even comes off somewhat. As a result, there is a chance that locally thicker deposits are formed, so that there is no longer a thin, tight film. These locally too thick deposits and any other undesired deposits such as calcium carbonate, result in a lower thermal conductivity. This reduces the efficiency of the heat transfer as the deposits increase.

Chemical cleaning

When the efficiency of the steam production of the boiler has become too low or if there is even a chance of blockages and leaks, it is often decided to chemically clean the water side of the steam boiler to remove the old magnetite layer and to provide it with a new thin magnetite layer.

Most suitable procedure

The most suitable cleaning procedure will be proposed by Vecom on the basis of, for example, a laboratory examination of the amount and composition of the deposit. If copper oxides are found during the research, certain standard cleaning procedures can be adjusted to dissolve these copper oxides.

Vecom often uses the following methods during post-commissioning cleaning of the water side of a power plant. As stated, copper oxides can be removed by adjusting the standard cleaning method.

  1. Cleaning based on hydrochloric acid
    Suitable for: carbon steel, copper
    Removes: iron oxides (rust), welding skin, mill scale and annealing skin.
  2. Cleaning based on hydrofluoric acid
    Suitable for: carbon steel, stainless steel, alloys with chrome or P91/92
    Removes: iron oxides (rust), welding skin, mill scale, annealing skin & silicate compounds.
  3. Cleaning based on citric acid
    Suitable for: carbon steel, stainless steel, alloys with chrome or P91/92
    Removes: iron oxides (rust), at high temperatures or after adding of additional chemistry, also suitable for removing mill scale and annealing skin.

Contact us

For more information or questions, contact one of our specialists.