分馏塔顶循环油换热器管束失效原因分析

文章对催化裂化装置分馏塔顶循环油换热器管束腐蚀穿孔原因进行了详细分析,指出换热器管外壁的腐蚀主要是H_2S-HCl-NH-3-H_2O型的全面腐蚀,管内壁主要是氯离子及氧的去极化引起的点蚀。腐蚀穿孔是由管外壁开始,并向管内壁发展,而管内壁的点蚀则加速了换热器管束的腐蚀穿孔。通过对换热器管束进行消除应力处理、采用相关“工艺防腐蚀”措施以及选用合适的耐蚀材料使腐蚀问题得到解决。

Analysis of Fractionator Overhead Recycle Oil Heat Exchanger Tube Failure

The detailed analysis of contusion failure of FCC main fractionator overhead recycle oil heat exchanger tubes,concludes that the corrosion of external wall of heat exchanger is mainly the comprehensive corrosion of H_2S-HCl-NH_3-H_2O while the internal corrosion is main- ly the pit corrosion by chlorine ion and oxygen depolarization.The corrosion failure starts from external wall and promulgates to the internal wall.The pit corrosion of internal wall accelerates the corrosion failure of heat exchanger tubes.The stress relief of the tubes,the applica- tion of process corrosion protection measures and the selection of the proper materials can effectively prevent the corrosion.