Good to know

Optimum protection against corrosion and deposits is essential for steam boilers and steam turbines in power plants as well as for heating and cooling systems (pumps, pipes, pipelines, heat exchangers, condensers, tanks, etc.).

What happens in unprotected water and steam systems?

The harmful substances in waste water include alkali metal salts, which are deposited on the heating surfaces at higher temperatures and form an insulating layer. This inhibits heat transfer. The insulating effect leads to increased energy consumption and reduced efficiency.

Under the deposited solid layer on the surface of the boiler tubes, overheating occurs, which leads to thermal stress cracks (thermal shock) and damages the boiler.

In addition, limescale deposits on vital components can impair their function. The same applies to cooling systems. Here, the precipitation and deposition of salts, e.g. on the fins of cooling towers, is favored by water movement, pressure, temperature fluctuations and evaporation and leads to the same technical and economic disadvantages as in steam operation. Detached corrosion and deposit particles circulating in the system cause erosion like sandpaper. Significant deposits also lead to an increase in circulation pressure. Both phenomena lead to a considerable reduction in the service life of the system (loss of production, repair and associated costs, need for premature investment). Iron and copper components are only resistant to the negative influences of (cooling) water and steam if they have an optimally thick, crack-free oxide layer on their surface. If the pH value is too high, this protective layer will peel off and lead to copper corrosion. A pH value that is too low leads to iron corrosion. It is therefore particularly important to set the optimum pH value range. To achieve optimum corrosion protection, the electrolyte content in the water should be kept as low as possible, ≤ 0.2 µS/cm. The conductivity, which is caused by the dosing of chemicals, also contributes to this. The content of dissolved residual oxygen should ideally be < 0.002 mg/l, usually < 0.005 mg/l. Summary The complexity of the above description makes it clear that when selecting the correct water treatment method (dosing points, chemicals, etc.) for optimal and economical operation, the quality of the water used, the properties and condition of the system, the type of user (e.g. engineering, food industry or pharmaceuticals) and general and local regulations and requirements must be taken into account, such as

MSZ EN 1074-1:2000 MSZ-09-85.0011:1988 MSZ 14121:1968 MSZ EN 442-1:1998 MSZ-09-85.0021:1989 MSZ-09-96.0721:1985 MSZ-09-96.0722:1985 MSZ-09-96.0723:1985 MSZ-09-96.0731:1985 MSZ-09-96.0732:1985 MSZ-09-96.0734:1988 MSZ-09-96. 0735:1988 MSZ 1752:1996 MSZ 4668:1983 MSZ 13834-2:1985 MSZ 14258:1983 MSZ EN 297:1997 MSZ EN 303-1:2004 MSZ EN 303-4:2000 MSZ EN 303-5:2000 MSZ EN 303-6:2000 MSZ EN 625:1998 MSZ EN 12952-1:2002 MSZ EN 12953-1:2002 MSZ EN 13445-1:2004 VGB Guidelines for Feed Water, Boiler Water etc. No. R450L; Technical Rules for Steam Boilers -TRD- of the German Steam Boiler Committee (DDA) and the Association of Technical Inspection Associations (VdTÜV); TRD611 - Data for steam generators of Group IV; Requirements for feed water for shell boilers according to EN 12953 Part 10 (except injection water)