Conforma Clad Helps Raichur Thermal Power Station Nearly Double Equipment Life

Problem:
The Raichur Thermal Power Station (RTPS) is located approximately 20 kilometers north of Raichur, India. It includes seven 210 MW capacity units that, combined, currently generate approximately 10,000 million units annually. The plant burns roughly 7 million tons of coal (40% ash) per year. With that amount of coal at 40% ash, erosion and wear are issues that RTPS has been facing.

RTPS was getting 8 to 12 months out of their coal nozzle tips. The tips were stainless steel (SS 310) with a 6mm layer of weld overlay for protection. Each year during their overhaul, they would refurbish the coal nozzle tips by replacing the eroded portion with a new stainless steel plate protected with the weld overlay. After two to three rounds of repair, it would be discarded and replaced with a new burner tip.

Solution:
In 2006, Kennametal Conforma Clad (Bangalore location) approached RTPS about using their infiltration brazed tungsten carbide cladding as protection on the plant's coal nozzle tips. Conforma Clad has been very successful at protecting and extending the life of burner tips and was sure t hey could help with the erosion issues RTPS was facing.

A field test was started in November 2006, placing two burner tips side by side in one of RTPS's units. One of the tips was the standard SS 310 weld overlay protected piece while the other was SS 310 protected with Conforma Clad’s infiltration brazed tungsten carbide cladding which is metallurgically bonded to the substrate. After one year of run time, both coal nozzle tips were pulled out and examined.

Results:
The weld overlay protected tip showed extreme erosion; the top splitter was completely eroded and severe erosion was found in the rest of splitters and partition plates. On the boiler side of the weld overlay protected tip, the inner annulus plate was severely eroded. The Conforma Clad protected tip maintained its size and shape and on the boiler side, showed no erosion. Using these results, it is expected that the Conforma Clad burner tip will last a minimum of 2 years.

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