POWER STATION - CORROSION CONTROL,
PRESERVATION AND ACCELERATED COOLING

The best way to solve high humidity problems in the preservation of equipment

  • Preserve equipment and to prolong its serviceability
  • Prevent corrosion on the surfaces of energy equipment, during is preservation
  • Reduce the costs of equipment preservation

In order to achieve these goals, it is necessary to choose an effective way to preserve equipment that will provide the best protection of corrosive surfaces from excessive humidity.

Why install industrial desiccant dehumidifiers in your power station?

  • Reduces costs of preservation of equipment
  • Reduces energy-consumption
  • Increases technical readiness of the power station
  • Prevents condensation
  • Prevents corrosion
  • Reduces the drying time of preserved equipment
  • Creates the necessary microclimate for preservation
  • Increases the serviceability of equipment

The main reason for occurrence and development of corrosion, and as the consequence for destruction of surfaces of units and mechanisms of the above-listed equipment is uncontrolled humidity.

At high relative humidity of 60-100% the rate of corrosion processes in steel is 100 – 2000 times higher than at a lower humidity of 30-40%.

The mechanism and rate of atmospheric (stationary) corrosion depends primarily on the humidity-level of the surface of the corrosive metal.

For example for boiler steels the critical relative humidity is 60%. At humidity higher than 60% the speed of atmospheric corrosion drastically increases g/m2h. As a result the thickness of the steel can reduce by up to 0.057 mm / year.

Dry air preservation retains the quality of equipment reduces repair and reconstruction costs by maintaining the safe parameters of the thermal power plant during shutdown.

Critical areas in a power station where desiccant air dryers are recommended during shut down include;

  • Re-heater tubes are much thinner than superheater tubes, and therefore more sensitive to corrosion. Inter-granular attacks on austenitic stainless steel can also be minimised by the constant supply of dry air.
  • Boiler – Condensate will form when the surface temperatures of fireside boiler tubing drops below the surrounding air dewpoint. This forms a highly acidic solution when the condensate reacts with sulphurous parts of the ash and acid deposits and hydrolyses. Resulting in damage to the internal metal surfaces.
  • Generator – To ensure a shorter restart time and to prevent corrosion it is important to keep the windings dry. As the Dry air is also warm it can additionally supplement generator heaters.
  • Reactor Vessel – To provide safe access, dry air is blown in to purge out CO2 and eliminate corrosion. In turn this will also help dry the graphite prior to recharging with CO2.
  • Re-heater tubes are much thinner than superheater tubes, and therefore more susceptible to corrosion. Inter-granular attacks on austenitic stainless steel are also minimised by the constant supply of dry air.
  • Condenser – to allow re-coating of water boxes and tube plates the internals of the condenser must be kept dry after flushing
  • Feed & Condensate Pipes – the constant flow of dry air will eliminate internal corrosion on pipes, this is especially important as oxides can contaminate feed water.

Contact one of our team today to find your humidity control solution...