Induced Draft Fan Blade Erosion Protection
Eroded ID fan blades and housing rebuilt cold and coated to resist ash-laden gas and extend the run between rebuilds.
The challenge
An induced draft fan pulls ash-laden flue gas across its blades and housing, and the suspended particulate wears the metal away wherever it strikes hardest. The leading edges of the blades lose profile first, the housing thins behind them, and the loss throws the rotor out of balance. As that wear spreads, the fan vibrates, moves less gas, and runs the risk of an unplanned trip. Left untreated, the blades and housing keep degrading until the fan has to come out for a full rebuild far sooner than the plant can afford.
Our approach
We take the rotor and housing where the metal has been carried away by the gas stream and bring it back. We blast the worn surfaces to clean, profiled steel, then rebuild the lost leading edges and the thinned housing with Belzona 1000 Series composites, working cold so the blades see no heat distortion that would warp the profile or shift the balance. Once the metal is back to shape, we apply an erosion-resistant coating over the blades and the high-wear paths so the new surface takes the particulate instead of the steel. The coating gives the gas a sacrificial face that is easy to renew at the next outage, which is what stretches the run between rebuilds.
- Assess and mapWe inspect the rotor and housing to locate where the ash-laden gas has eaten the leading edges and thinned the metal, and confirm the wear paths through the fan.
- Surface preparationWe grit-blast the worn blades and housing back to clean, profiled steel so both the rebuild and the coating bond properly.
- Cold rebuild leading edgesWe rebuild the lost leading edges and thinned housing with Belzona 1000 Series composites, working cold so the blades take no heat distortion.
- Apply erosion-resistant coatingWe coat the blades and high-wear paths with an erosion-resistant system that gives the gas stream a sacrificial face instead of bare steel.
- Cure and return to serviceWe confirm cure and check the finished profile, then hand the fan back ready to run within the outage window.
The result
- Eroded leading edges and housing rebuilt in place without replacing the rotor
- Blades returned to profile cold, with no heat distortion to the balance
- Erosion-resistant coating gives the ash-laden gas a sacrificial face that renews at outages
- Longer run between fan rebuilds, delivered by factory-trained and factory-certified Belzona applicators
Belzona systems used
In the field
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