Acid Dew Point Corrosion

By Steven Williams posted 03-13-2017 08:07 PM

As a veteran in the industrial coatings business without question corrosion caused by condensing flue gases can be the worst. Not only is this type of corrosion damaging to very critical assets it is very costly. As fuels are burned the gases travel through the systems ducts, scrubbers, baghouses, hoppers and stacks become subject to this type of corrosion if interior steel temperatures drop below the acid dew point. Rapid heat loss is what causes this problem as hot goes to cold the gases condense from gas state to liquid state forming acid enriched condensation on the interior steel surfaces.

Over the years as a coatings contractor the answer to these problems were high solid epoxies or vinyl ester systems and linings. Thicker would seem to be better well at least till it had to be replaced or repaired. 60 to 120 mil thick coating materials lining equipment presents their own problems cost, time to install, temperature tolerance and service life or repairs as these harsh conditions attack the coating. These problems have lead many plants to convert from carbon steel to stainless or other alloy wall paper process to gain longer life and minimize problems. But again this approach can be very cost prohibitive and marginally effective if you're not able to treat the entire system.  

Both the approaches I mention do not address the core problem which is rapid heat loss creating cold spots throughout the system. As you travel throughout the country you'll commonly see power plants with metal cladding with conventional insulation materials under this metal sheeting. But its what is hidden under this metal cladding we have found to be the real problem. Conventional insulation materials such as mineral wool do not block heat energy at the metal but allows heat loss from the equipment into the insulation the insulation material. And as the material is subject to atmospheric conditions and moisture the effectiveness is less and less. Most of the time plants have to install heaters to equipment because the insulation materials cannot keep steel temperatures elevated. Corrosion, ash build up and heat stratification creates real maintenance headaches.

What's the answer ceramic thermal barrier coating technology! Eliminate acid dew point corrosion, build up due to condensation, need for exterior heaters and heat stratification by encapsulating equipment with spray applied ceramic coating system. 200-300 dry film thickness DFT out performs 20 inches of conventional insulation. How can that be... our ceramic material creates a heat block at the steel surface and the unique suspended ceramic compounds remits heat energy back into the steel. This block only allows the steel to cood as the gas or ash it's self cools keeping the temperature spread well above the acid dew point. 

This technology is a game changer for WTE and Coal Burning plants and even better the material likes to be applied when the steel is hot minimizing down time and maintenance. High temperature resin infused with ceramic compounds is a cost effective approach to solving numerous problems want to hear more I would love to connect.