炼油厂石蜡成型原料夹套管腐蚀失效分析

Study on Corrosion Failure of Jacket Tubes of Wax Molding Unit in Refinery

介绍了炼油厂石蜡成型装置的结构和工艺流程,在运行过程中发现管线多次泄漏,并且泄漏都是发生在水侧的坑状腐蚀。对腐蚀形态、产物和介质的分析表明,管线的腐蚀不论是点蚀还是全面腐蚀,氧是碳钢在水介质中腐蚀的关键因素;耗氧反应的不断进行,促使阳极金属不断溶解,引起的金属腐蚀为氧腐蚀;氯离子的存在使反应生成了铁离子加剧了腐蚀的进行。通过采取措施如适当降低热水温度、减慢水流速度和定期地更新水质防止氯离子浓度不断升高可以有效地降低腐蚀的速率。

The configuration and process flow of the wax molding unit in a petroleum refinery are described. Corrosion leakages occurred many times on pipelines in unit operation , and the corrosion was pit corrosion on the water side. The analysis ofcorrosion form, corrosion product and corrosive media shows that oxygen is the important factor of corrosion of carbon steel in water whether it is pit corrosion or overall corrosion. The continuous oxygenation reaction accelerates the continuous dissolving of the anode metal, resulting in oxygenation corrosion of metal. In addition, iron ions formed from reaction in the presence of chlorine ions at lower concentration has accelerated the corrosion. The taking of effective measures, such as properly lowering the temperature of hot water, reducing water flow velocity and regularly replacing water to prevent continuous concentration of chlorine ions, can effectively reduce the corrosion rate.