Repair & Rebuild of Fly Ash Pipeline Elbow



Vigorous erosion was noticed on various carbon steel fly ash elbows installed at a Thermal Power Station. Erosion were primarily due to the inability of these carbon steel structures to handle the abrasion levels of the high temperature (up to 200°C) dry fly ash passing through these pipelines. This resulted in frequent dismantling of the eroded elbows, thereby not only causing delays but also drastically increasing the Operations & Maintenance cost for the Power Station.




Upon assessing the situation and associated problems, Arudra identified that multiple thick layers of high temperature - abrasion resistant 100% solid epoxy putty’s would be required to protect these elbows from the erosive high pressure & temperature intense operating conditions.

A blasted carbon steel plate was welded onto the elbow to cover up the eroded portion.

A buffing technique was further used to re-do the damaged surface internally and externally. A thick layer of Duromar - HAR was then applied on both the internals and external side of the elbow. Duromar HAR is a 100% solid thick Carbide Putty with outstanding Abrasion and High Temperature resistance.

In order to increase the adhesion levels, multiple layers of Duromar EXP - Thixset was applied on top of the HAR material, on both sides of the damaged portion of the elbow. Duromar EXP - Thixset is a thicker 100% solid epoxy putty than Duromar HAR, which has high temperature & chemical resistance that helps enhance long term flexibility of the protective coating


Upon installation, it was noted that application of the High Temperature & Abrasion resistant 100% solid epoxy putty’s helped protect the carbon steel elbow from any further erosion/corrosion related issues under the extreme operating conditions. The epoxies not only helped rebuild and enhance the Asset Life of the Fly Ash Elbow, but also helped eliminating unforeseen Operations & Maintenance costs.