At the same time that pitting corrosion occurs, the sulfur in the coal and sulfides such as H2+S will undergo high-temperature sulfide corrosion with the steel plate at the bottom of the jacket under high temperature conditions, H2+S+Fe → FeS+H2+, S+Fe → FeS. Under the combined action of pitting corrosion and sulfide corrosion, the steel plate at the bottom of the jacket becomes thinner.

The temperature of the inner tank of a single-stage gas generator is very high, and the internal reactions are complex. During daily production, the oxide layer releases a large amount of heat, causing the temperature of the furnace tank to reach over 1200°C, and the middle temperature of the inner tank to reach around 1400°C. At this time, the cooling water in the jacket plays an important role in protecting the inner tank steel plate. When the jacket is short of water or has no water, it will cause the furnace body steel plate to overheat and possibly deform. If the operation is incorrect at this time and the water is replenished urgently, the jacket pressure will suddenly increase, causing the jacket to deform, and the furnace body may burst, causing casualties and economic losses.

In daily production,Single stage gas generatorThe steel plate of the inner tank has been in a high temperature and high humidity environment for a long time, and the mechanical properties and corrosion resistance of the steel plate are greatly reduced. The humid water environment makes the steel plate prone to electrochemical corrosion. After a large number of anions are adsorbed on the metal surface, the passivation film on the surface of the steel plate is destroyed. After the passivation film is destroyed, the steel plate lacks self-passivation. Ability, corrosion occurs on the surface of the steel plate. The surface defects of the corroded steel plate easily leak out of the body metal, which is in an activated state, while the passivation film is still in a passive state. Since the anode area is small and the anode current density is large, the corrosion continues to develop deeper, and the surface of the steel plate is quickly corroded into small holes, forming pitting corrosion.

The sulfur content of coal is generally high. Under high temperature and humidity conditions, a series of oxidation-reduction reactions occur between sulfur and the oxygen in the gasification agent and the carbon in the coal in the oxidation layer and the reduction layer, generating SO2 and H2+S. In a water environment, acid liquid is generated, and the steel plates of the single-stage gas generator will be corroded by the acid liquid. At the same time, due to the decrease in PH value and the increase in temperature, this increases the possibility of pitting corrosion. The Fe3+ generated after corrosion of the steel plate can cause pitting corrosion to occur. Therefore, the steel plate in the oxide layer will continue to suffer from pitting corrosion.