Enhanced protection through laser coating technology increases life of thermal power plant boilers by 2-3 times

Vijay Mohan

Tribune News Service

Chandigarh, October 7

Indian scientists have developed a unique laser-based clad coating technology (LCCT) that provides improved protection to boiler parts in thermal power plants. This can enhance the life of boiler parts by 2-3 times as compared to currently in use surface coating technologies.

It has been found that this technology is suitable not only for boiler parts of thermal power plants but also for any engineering application involving high temperature erosive and corrosive environments.    

Laser cladding is a technique for fusing a coating material on a substrate. It allows materials to be deposited accurately, selectively and with minimal heat input into the underlying substrate. Such a process leads to property improvements of the surface of a component, including better wear resistance, thus allowing for the repair of damaged or worn out surfaces..

In advanced supercritical and ultra-supercritical thermal power plants, various parts of the boiler and its accessories such as feeder nozzle tip, re-heater boiler tube bends and burner spreaders often degrade due to severe wear and corrosion at high temperature, requiring frequent replacement during breakdown or maintenance schedules.

Shutdown due to such problems severely affects power production. Failure of components during the running period of the plant makes the maintenance job challenging and cumbersome due to the prevailing high temperature and dust enveloped conditions and leads to a massive loss in production in coal-fired power generation plants.

To overcome this challenge, scientists from the International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), an autonomous institute of the Department of Science and Technology, came up with the LCCT, for which an Indian patent has also been granted, according to a statement issued by the Ministry of Science and Technology, today.

The LCCT is a meticulous fusing of a nickel-based soft matrix with hard metallic carbide particles of tungsten, chromium, or vanadium that is coated on steel parts by employing a high-power laser.    

The patented LCCT has been successfully tested for feeder nozzle tips of boilers for 200 and 500 megawatt plants belonging to the National Thermal Power Corporation. Field results have indicated 2-3 fold life enhancement of LCCT driven boiler parts compared to other surfacing technologies. 

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