Dry Scrubber Wall Surface Loss Reduced

NanoSteel coating provides severe corrosion resistance for extending dry scrubber chamber service life

Problem: Severe Corrosion and Pitting Damage

Spray drying absorption (dry scrubber) systems remove sulphur dioxide from flue gas at fossil fuel power plants. This process occurs inside a chamber fabricated from A36 carbon steel.

As flue gas enters the chamber at 300° F, a mixture of fly ash, lime milk and cooling tower blowdown water is sprayed to absorb sulphur dioxide into alkaline droplets. As the water evaporates almost immediately, the droplets are converted to a powder which falls to the bottom of the chamber for removal.

Where spraying occurs, a combination of corrosion scale, fly ash and lime milk containing high concentrations of calcium sulfite, calcium sulfate and chlorine can build up on the ID surface of the chamber wall and cause severe corrosion and pitting damage. This damage can result in significant wall material loss and cause the chamber to buckle and fail.

 

    Solution: NanoSteel Thermal Spray Coating

    To reduce material loss inside dry scrubber chambers at a coal fired power plant in Arizona, a NanoSteel SHS 7570 TWAS thermal spray coating is applied for resisting corrosion and pitting.

     

      Result: Improved Corrosion Resistance and Longer Service Life

      The NanoSteel SHS 7570 TWAS thermal spray coating provides resistance to severe corrosion and pitting damage, reduces wall material loss and extends the service life of the dry scrubber chamber.

      Corrosive material build up

      Corrosion scale, fly ash and lime milk builds up on chamber ID wall surface

      Corrosive Material Build Up in Dry Scrubber Chamber

      Resulting Catastrophic Chamber Wall Failure

      Significant surface material loss caused the wall of this dry scrubber chamber to buckle and fail

      Dry Scrubber Chamber Wall Failure

      NanoSteel Coating Prevents Material Loss

      NanoSteel coating provides severe corrosion resistance, reduces wall material loss and extends the life of the dry scrubber chamber

      NanoSteel Coating Extends Dry Scrubber Chamber Life
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