Ammonia filling method for boiler protection

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The ammonia filling method is generally used for the protection of power plant boilers during long-term shutdowns. Since ammonia is corrosive to copper, when using the ammonia filling method, all copper components in the boiler’s steam and water systems must be removed or sealed off. The ammonia filling method involves filling the boiler with ammonia gas after draining it when the boiler is not in use, maintaining the ammonia pressure inside the boiler at 13 kPa in order to expel air and reduce the oxygen content in the water film on the metal surface. Since ammonia, when dissolved in the water film, confers good corrosion resistance to metal surfaces, the ammonia filling method does not have strict requirements regarding the dryness of the metal surface; however, it is necessary that the entire system be leak-free. Use a moist red litmus paper to check the areas where ammonia leakage may occur; if the paper changes from red to blue, it indicates an ammonia leak, and sealing the leak should be carried out immediately. Open-flame operations should also be strictly prohibited to prevent explosions.