Corrosion of flue gas reheater for sewage incineration 1

[Housemouse]

Flue gas is reheated in a 2-stage reheater for plume supression, low pressure steam is provided for reheat and limited to 190oC. Reheat stage-1 has protective coating protect against dew-point corrosion. Reheat stage-2 constructed from mild steel. Flue gas temp is:

35-45oC to 70-85oC to 110-115oc to atmosphere.

Flue gas composition:
Inorganic compounds of chlorine as HCl 10mg/m3
Sulphur dioxide & sulphur trioxide as SO2 50mg/m3
Nitrogen monoxide and dioxide as NO2 200mg/m3

Reheat-2 has serious corrosion, can anyone suggest a suitable replacement material or protective paint to use for new reheater, or is sacrificial anodes an option.

Many Thanks

 

[Knorris]

Mr. Housemouse

A good material or coatings for your problem is a ceramic. First choices of material is Cr-oxide or Zr-oxide widely used in the chemial industry. Try to contact a metallizing company in your area that has a plasma unit. If no luck contact us at the below address. We have field services.

http://www.hvof.com

knorris@hvof.com

 

[rustbuster1]

Organic protective coatings can prevent dew point or condensate corrosion at the temperatures you list. You should evaluate both 100% solids, epoxy novolac and also vinyl ester coatings. Companies like Plasite and Blome International have both of these types of coating in their product lineups and should be able to help you evaluate or even test them to devise the best solution. Thermal spray coatings can work too but typically are approx. 10 times more costly than high-performance organic coatings. Search for the above companies on

http://www.google

.com