减压塔三线集油箱支撑梁局部产生腐蚀原因

对某厂减压塔三线集油箱支撑梁局部部位产生腐蚀的原因及改进措施进行了研究。对支撑梁蚀坑形貌的检查和分析表明该腐蚀为小孔腐蚀。对支撑梁的化学成分分析及对机械性能的检验表明支撑梁的材质发生了误用,0Cr18Ni9Ti奥氏体不锈钢误用为00Cr17Ni14Mo2奥氏体不锈钢。对支撑梁的金相检验表明其基体组织正常。电子探针的分析结果表明支撑梁局部腐蚀部位外表面的腐蚀产物中含有S2-和Cl-。通过分析小孔腐蚀机理和腐蚀条件,提出3种解决方案:应采用00Cr17Ni14Mo2奥氏体不锈钢;限制并降低进入减压塔内的常压重油中的杂质含氯的无机盐和氧的有机化合物的含量;采用阴极保护的方法。

Analysis of Corrosion on Local Position of Supporting Beam of Accumulator Tank in Decompression Tower

The cause of corrosion on the supporting beam in some one finery was studied, and strategy of improving measure was researched. The check and the analysis of the pattern of corrosion pit indicated that it was pit corrosion. The analysis of chemical component and mechanical performance check suggested that the material had been misused: 00Cr18Ni9Ti had been misused as 00Cr17Ni14Mo2. The microstructure observation showes that the microstructure is normal. The electron probe micro-analysis shows that the corrosion products are composed of S2- and Cl-. After analyzing the mechanism of corrosion and its condition, the following suggestions were put forward: 00Cr17Ni14Mo2 steel should be applied; the percentage of inorganic salt and organic compound in heavy oil entering to decompression tower should be limited; and the method of sacrificial corrosion should be taken.