What are the functions of boiler anti-corrosion spraying in the industry

       

Boiler anti-corrosion spraying is a coating method that is dispersed into uniform and fine droplets by means of pressure or centrifugal force through a spray gun or disc atomizer, and is applied to the surface of the object to be coated. Due to the presence of a large amount of sulfur and other harmful impurities in the coal used in the boiler, the temperature in the furnace can reach 1600 °C during the operation of the boiler. The water-cooled wall forms high-temperature corrosion, which leads to reducing atmosphere corrosion, molten salt corrosion formed during the combustion of metal oxides, and H2SO4 corrosion formed by dissolving sulfides in water. main reason.

The hazards of high temperature corrosion of boilers mainly include sulfides, alkali metal salts and vanadium salts generated during the combustion process. These chemicals jointly carry out a complex corrosion process on the tube wall under the action of high temperature. The main factor is the high-temperature corrosion of sulfides in coal combustion. When high-sulfur coal burns in an environment with insufficient oxygen in the boiler, it is easy to generate corrosive gases such as hydrogen sulfide, and sulfur-containing substances in flue gas produce single atoms at high temperatures Sulfur reacts with iron in the pipeline to form iron sulfide, which will destroy the protective film of the pipe wall at high temperature and erode the pipe directly and react with metal iron, resulting in the continuous thinning of the metal pipe wall to form corrosion. The other is that non-combustible sulfur generates sulfate under the action of high temperature, which is mixed with the burning ash powder, and attaches to the surface of the pipe wall to form corrosion, which leads to the reduction of the useful wall thickness of the water-cooled wall pipe and reduces the water-cooled wall pipe. The high-temperature mechanical properties of the water-cooled wall continuously reduce the effective bearing capacity of the water wall. In addition, the water used has not been treated, which leads to serious scaling of the boiler, and gradually blocks the water-cooled wall tubes. Under the action of long-term high temperature, the water-cooled wall is gradually corroded and the wall thickness is reduced.