Frequently Asked Questions (FAQ)
Will GreenShield be appropriate for all my wear areas?
GreenShield will protect all but the most aggressive wear areas in your combustor. In fact, GreenShield will protect over 95% of the areas prone to abrasion in your combustor. Many power plant operators use GreenShield to determine precisely where these extraordinary wear areas are located. This is accomplished due to the green colour of GreenShield. If during your second outage, the coated areas are still green, you will know that there was zero tube wastage. You will also be able to see at a glance the most aggressive wear areas that may require weld overlays. This GreenShield feature will save you money and time as any weld overlays and or metal spray products are only used where they are absolutely required.
How does GreenShield protect against corrosion and slag buildup?
GreenShield has an extremely low porosity; it seals the exposed metal tubes and functions as an impervious membrane. This GreenShield feature prevents the initial sintering process and stops the slagging material from anchoring itself to the water wall tubes. Any slagging material that has not formed sufficient mass to fall off under its own weight is easily brushed off.
How fast can you apply GreenShield?
The FMP crew can apply 1,500 square feet of GreenShield in one shift.
Does GreenShield impede heat transfer through the water walls?
No, FMP has conducted the Chordal thermocouple test which showed equal heat transfer through coated and uncoated tubes. GreenShield actually increases heat transfer because it prevents the insulating properties of slag to build up.
How much does GreenShield cost?
GreenShield is priced at about one-fifth the cost of the least expensive metal spray. FMP prices each job individually, predicated on the total square footage.
How long will GreenShield last?
That depends on how aggressive the wear is. We have had coated economizers in service for over 3 years with zero tube wastage. At each scheduled outage, FMP will measure the thickness of the remaining GreenShield and re-apply coating to bring the thickness back to the original. GreenShield will adhere to itself.
Can GreenShield protect other areas at my facility?
It really depends on the application and service temperature. FMP offers additional products like CeramaClad and EnerCote that have been used successfully to line duct work, bag houses and repair water boxes.
Can you coat over metal spray products?
FMP is able to coat over freshly applied metal spay, however if the metal spray has been in service for sufficient time to allow the surface to become smooth, FMP would first have to profile the surface.
Is GreenShield safe?
FMP will provide an MSDS which will assure you of its safety. GreenShield is non-toxic and non-flammable.
Why is GreenShield green?
GreenShield is green due to the chemical compounds that are used to formulate the product.
How does it reduce NOx?
A cleaner tube surface free from slag and oxide scale improves heat transfer and the furnace can operate at a lower temperature to maintain its desired heating. Several FMP products including GreenShield, BlackStone and Refraxe offer high emissivity. NOx emissions is related to flame temperature and flue gas temperature. An affect of high emissivity coatings on a furnace surface is to change the surface to as close to black body as possible. When Refraxe is applied over top of refractory there is a significant change in the refractory surface emissivity. An increase in radiant heat transfer efficiency allows for more radiant absorbed duty per energy employed, this leads to lower flue gas temperatures.
What are the limitations of GreenShield?
As with any of our water based inorganic ceramic coatings the curing temperature is a limitation. The service temperature must be at least 500oF for the coating to provide adequate protection. The coating cannot be used for immersion service in water and before curing the coating must remain free of water or high moisture contact.