高温下环烷酸与硫耦合腐蚀实验研究

Coupled Erosive Behavior of Naphthenic Acid and Sulfur at High Temperatures

在炼油过程中,环烷酸与硫同时存在,它们的耦合腐蚀成为影响炼油企业生产的重要因素。通过模拟炼油现场腐蚀情况,在高温反应釜中开展了环烷酸与硫耦合腐蚀行为的实验研究,同时采用EDS和XRD对腐蚀产物膜进行分析。结果表明:高温下,Q235和316不锈钢在单独硫介质中的腐蚀速率呈现出先增加后减小的趋势;在环烷酸与硫耦合腐蚀情况下,当硫含量为1%(质量分数),随着酸值的增加,Q235钢的腐蚀速率呈一直增加趋势,当酸值大于9mgKOH.g-1时其速率增加趋势变大;而316不锈钢腐蚀速率先增加后减小再增加,使得316不锈钢存在临界酸值9mgKOH.g-1和12mgKOH.g-1;在酸值为9mgKOH.g-1时,随着硫含量的增加,316不锈钢腐蚀速率先增加后减小,Q235钢腐蚀速率则一直增加;通过腐蚀产物膜形貌分析发现Q235钢腐蚀产物膜物相是疏松的Fe7S8;硫含量、酸值以及温度影响环烷酸与硫耦合作用下的腐蚀产物膜形貌。

Naphthenic acid and sulfur exist simultaneously during the refining process,and so its coupled coordination corrosion affects the manufacture of oil refining enterprises.By simulating the corrosion of oil field,the coupled coordinated corrosion research of naphthenic acid and sulfur was carried out in high-temperature reactor,and then the corrosion products were analyzed by EDS and XRD.The results show that at high temperature,in sulfur only medium,the corrosion rate of two kinds of steels increases firstly and then decreases with the increase of mass fraction of sulfur;in the condition of coupled coordinated corrosion,when sulfur content is 1%（mass fraction）,with the increase of acid value the corrosion rate of Q235 increases all the way,and the increase tendency of corrosion becomes bigger when acid value is over 9mgKOH·g-1;while the corrosion rate of 316 steel increases firstly,decreases secondly and then increases,so 316 steel has two critical acid value of 9mgKOH·g-1 and 12mgKOH·g-1;when acid value is 9mgKOH·g-1,with the increase of mass fraction of sulfur the corrosion rate of 316 increases firstly and then decreases,while Q235 increases all the way;after analyzed the corrosion films,found that the corrosion film of Q235 steel has crumbly Fe7S8;sulfur content,acid value and temperature affect the corrosion membrane morphology of coupled coordinated corrosion.