渗铝钢在高酸值原油中的耐腐蚀机理

Corrosion-resisting Mechanisms of Al-diffused Steel in High TAN Crude Oils

渗铝钢耐环烷酸腐蚀的性能远远超过1Cr18Ni9Ti不锈钢,与316 L不锈钢耐蚀性能相当。改进型固体粉末渗铝钢主要由FeAl相构成。在高油气流冲刷下和高温环烷酸腐蚀环境下,碳钢表面形成的FeS膜不具备保护性,而渗铝钢的渗层表面形成了均匀、致密、非常薄、附着力强及修复速度快的Al_2O_3保护膜。虽然这种氧化膜同时受到环烷酸的溶解作用及Cl^-渗透、S的影响,但FeAl合金层可以提供足够的Al来保持Al_2O_3膜,这是渗铝钢耐高温环烷酸腐蚀的主要原因。

The resistance of Al-diffused steel to naphthenic acid corrosion is much more superior over that of 1Cr18Ni9Ti stainless steel and equivalent to that of 316 L stainless steel. The modified A1 powder diffused steel mainly consists of FeAI phase. Under the erosion of high-velocity oil vapor and high-temperature naphthenic acid corrosion environment, the FeS film formed on the carbon steel surface no long provides protection. Whereas, in Al-diffused steel, a uniform, compact, thin and cohesive Al2O3 protection film is formed on the surface. Although the Al2O3 film is subject to the dilution of naphthenie scid, penetration of Cl^- and impact of sulfur, the FeAl alloy layer can provide sufficient Al to maintain Al2O3 film. This is why the Al-diffused steel is resistant to naphthenic acid corrosion.