Paint system for Aboveground Storage Tanks in Marine+Acidic environment
Paint system for Aboveground Storage Tanks in Marine+Acidic environment
(OP)
I am responsible for upgradation of the external paint system on a number of carbon steel aboveground storage tanks at a chemical plant.
The environment that the paint system will have to protect against is:
1. Marine conditions - we are a stones throw from the sea.
2. Moisture - Spray of chemical-dosed water from nearby cooling towers
3. Acid - There is some concentration of acetic acid and hydrochloric acid in the air.
4. Caustic - There is a caustic plant in the neighborhood, as well as Caustic storage/processing at our plant.
5. Chlorine and other chemicals - we are located in an industrial zone with a number of chemical plants nearby.
6. Temperatures in excess of 40 C/104 F for much of the year.
7. Smoke, unburnt hydrocarbons and other combustion products from next-door steel processing facility.
The original paint system was:
Primer: 2 pack epoxy zinc phosphate - 75 DFT
Intermediate: 2 pack high build epoxy - 125 DFT
Finish: Acrylic Urethane - 125 DFT
Minimum surface prepapration specified was SSPC-SP10.
The system failed with widespread blistering and through holes in the tank roofs which we have had to repair.
What paint system can I apply to achieve the most comprehensive protection with least amount of maintenance?
Thanks!
Shaafi
The environment that the paint system will have to protect against is:
1. Marine conditions - we are a stones throw from the sea.
2. Moisture - Spray of chemical-dosed water from nearby cooling towers
3. Acid - There is some concentration of acetic acid and hydrochloric acid in the air.
4. Caustic - There is a caustic plant in the neighborhood, as well as Caustic storage/processing at our plant.
5. Chlorine and other chemicals - we are located in an industrial zone with a number of chemical plants nearby.
6. Temperatures in excess of 40 C/104 F for much of the year.
7. Smoke, unburnt hydrocarbons and other combustion products from next-door steel processing facility.
The original paint system was:
Primer: 2 pack epoxy zinc phosphate - 75 DFT
Intermediate: 2 pack high build epoxy - 125 DFT
Finish: Acrylic Urethane - 125 DFT
Minimum surface prepapration specified was SSPC-SP10.
The system failed with widespread blistering and through holes in the tank roofs which we have had to repair.
What paint system can I apply to achieve the most comprehensive protection with least amount of maintenance?
Thanks!
Shaafi





RE: Paint system for Aboveground Storage Tanks in Marine+Acidic environment
Steve Jones
Corrosion Management Consultant
http://www.linkedin.com/pub/8/83b/b04
All answers are personal opinions only and are in no way connected with any employer.
RE: Paint system for Aboveground Storage Tanks in Marine+Acidic environment
You could replace the epoxy with a polysiloxane- more expensive but definitely more resistant than either the polyurethane or the epoxy, but both of those are good finishes and quite acid/base/chloride resistant- and you had the organic zinc underneath too...
Thermal spray aluminum isn't going to survive the acid exposure unless you top-coat it with something, again unless I'm missing something which makes the coating more resistant than solid aluminum.
RE: Paint system for Aboveground Storage Tanks in Marine+Acidic environment
I suspect that poor surface preparation is the problem. Salt spray on the surface before painting will lead to blisters.
RE: Paint system for Aboveground Storage Tanks in Marine+Acidic environment
JPCL,PCE, March 2005, pp 48 - 50
Steve Jones
Corrosion Management Consultant
http://www.linkedin.com/pub/8/83b/b04
All answers are personal opinions only and are in no way connected with any employer.
RE: Paint system for Aboveground Storage Tanks in Marine+Acidic environment
I am looking into polysiloxane and thermal spray aluminium. Im also going through ISO 12944 which has some useful info.
I will try to update this thread with some pictures of the failure mode of our original system.
I strongly suspect that the failure was related to improper application. Since we're dealing with large surface areas and a seaside location, perhaps flash rusting/condensation may have had a role to play.
Thanks again for your inputs.
Shaafi
RE: Paint system for Aboveground Storage Tanks in Marine+Acidic environment
I suspect a salt contamination during application. If your surface has not been properly cleaned and checked for salt contamination (bresle, scm400...) before application of your epoxy zinc phosphate, you surely have a large amount of salt under your paint system.
RE: Paint system for Aboveground Storage Tanks in Marine+Acidic environment
RE: Paint system for Aboveground Storage Tanks in Marine+Acidic environment
Interestingly enough the paint on the tank shells did not deteriorate very much.
RE: Paint system for Aboveground Storage Tanks in Marine+Acidic environment