Effect of sodium vanadium complex on the protective layer of metal oxide film

The disadvantage of increasing the temperature of the exhaust gas is increased heat loss and reduced thermal efficiency. However, for enterprises whose industrial furnace combustion conditions are relatively inadequate, the increase of the temperature of the exhaust gas may be a method of delaying low-temperature corrosion. In addition, for the part of the metal wall temperature close to or below the acid dew point, you can additionally take the following two measures: metal flue or chimney plus insulation, in order to reduce flue gas in the flue or chimney heat loss, to ensure high flue gas temperature Dew point in acid.

Reducing the water vapor component of flue gas The increase in water vapor mainly increases the low-temperature corrosion degree from two aspects: at the same temperature and in the case of sulfur trioxide, the more water vapor, the more sulfuric acid vapor is generated. U In the same sulfur trioxide The higher the water content, the higher the dew point of the water and the greater the amount of water condensation, the more liquid sulfuric acid is produced. In particular, for the use of water vapor atomization, the amount of atomized water vapor must be strictly controlled under the premise of meeting the full combustion requirements.

Cleaning ash deposits also plays a catalytic role in low-temperature corrosion. The ash accumulated on the metal wall will undergo a series of physical and chemical reactions with sulfuric acid to form a "cement-like" white slime, which contains vanadium, sodium and sulfur compounds. It is theorized that the continuous action of the sodium vanadium complex on the protective layer of the metal oxide film is the cause of accelerated corrosion. In addition, this slime will absorb more ash and sticky mud coagulation down, playing a vicious cycle, adding low temperature corrosion of heavy metal walls. Therefore, these accumulated dust must be regularly removed.