A coal burner nozzle erodes from the inside out, and by the time a flame pattern visibly changes, the underlying wear has usually been progressing for far longer than anyone realized.

Why Burner Nozzles Wear and Why It Matters

Coal burner nozzles operate under a uniquely harsh combination of extreme heat, abrasive particulate flow from pulverized coal, and repeated thermal cycling as burners fire and idle across a plant’s operating schedule. The abrasive nature of coal particulate accelerates erosion at nozzle surfaces compared to gas or oil firing, and once erosion changes a nozzle’s internal geometry even slightly, it can affect flame pattern, combustion efficiency, and in some cases increase emissions as combustion becomes less complete. Catching nozzle wear early and addressing it with a targeted repair, rather than waiting for a flame pattern problem to force attention, keeps combustion performance consistent between scheduled nozzle replacements.

What a Burner Nozzle Repair Compound Needs

Repairing coal burner nozzle erosion calls for a putty that offers:

• Extreme sustained temperature resistance, since burner nozzle tips operate at some of the highest sustained temperatures in a coal-fired system, often exceeding 2,000°F.
• Abrasion resistance, given the continuous exposure to pulverized coal particulate flow that caused the original erosion.
• Strong adhesion to nozzle metal substrates, typically high-temperature alloy steels engineered for burner service.
• A stable, precisely applicable cure that can restore original nozzle geometry accurately rather than just filling a defect approximately.

Incure’s Approach to Burner Nozzle Repair

Incure’s Epo-Weld™ high-temperature putty is a ceramic-filled, one-part paste suitable for addressing erosion and minor damage on burner nozzle surfaces. It’s formulated to cure to a hard, abrasion-resistant, ceramic-reinforced state capable of withstanding continued particulate exposure, and its workable, moldable consistency allows technicians to restore nozzle contours with reasonable precision during the repair process.

Repair Procedure for Burner Nozzles

1. Schedule the repair during a planned outage, allowing the burner to cool fully and providing safe, direct access to the nozzle assembly.
2. Clean the eroded area thoroughly, removing loose scale, ash deposits, and any friable material to expose sound base metal.
3. Apply the putty to restore the original nozzle contour as closely as practical, using reference measurements or a template where available to maintain accurate flame geometry.
4. Cure fully per specification before returning the burner to a controlled, gradual startup.

Restoring nozzle geometry approximately, without reference to original dimensions, is a common reason a repaired nozzle produces an altered flame pattern even after the erosion itself has been addressed — taking careful measurements before erosion progresses further, or referencing OEM nozzle drawings, meaningfully improves repair accuracy. If you’re planning nozzle repairs and want guidance on restoring precise geometry for your specific burner design, Email Us.

Building Nozzle Inspection into Routine Maintenance

Because coal particulate erosion progresses gradually and predictably rather than suddenly, tracking nozzle wear rates across scheduled outages helps plant engineers anticipate when a repair or full nozzle replacement will be needed well before it affects combustion performance. Facilities that measure and log nozzle dimensions at each outage build a wear-rate history that makes future maintenance planning considerably more precise than reacting only after a flame pattern problem is observed during operation.

Common Questions on Burner Nozzle Repair

Q: How much erosion is too much for a putty repair?
A: Erosion that has significantly altered the nozzle’s overall geometry or reduced wall thickness substantially generally calls for nozzle replacement rather than a putty repair, since a repair works best when it’s restoring a moderate defect rather than compensating for extensive material loss.

Q: Does coal type affect erosion rate?
A: Yes — coal with higher ash and particulate content tends to accelerate nozzle erosion compared to lower-ash coal, which is a useful factor to weigh when setting inspection and repair intervals for a specific plant’s fuel supply.

Q: Can repaired nozzles be reused indefinitely with periodic touch-ups?
A: Nozzles can generally be repaired multiple times over their service life, but each repair should be evaluated against the nozzle’s original design tolerances — a nozzle nearing the end of its practical repair life is usually better replaced than repaired again.

Related Reading

Because thermal expansion mismatch between repair compounds and high-temperature alloy substrates is relevant to understanding repair durability under repeated firing cycles, our explainer on how CTE mismatch causes adhesive bond failure offers useful background. Facilities also managing thermally emissive coatings on adjacent boiler components should review our guide to Epo-Weld™ HECC ceramic coatings by substrate and service temperature.

Coordinating nozzle repair timing with a plant’s broader combustion tuning schedule also helps — restoring nozzle geometry right before a combustion efficiency assessment gives the clearest picture of whether the repair fully addressed the erosion-related performance drift, rather than conflating it with other seasonal or fuel-supply variables.

Contact Our Team to discuss the right high-temperature putty for your coal burner nozzle repair needs.

Visit www.incurelab.com for more information.