酸性水汽提塔顶回流进料分布管腐蚀原因分析

Cause analysis of corrosion of top reflux distribution pipe on sour water stripper

针对酸性水汽提塔顶部的顶回流分布管、生气孔顶板等内构件的腐蚀问题进行了原因分析,并提出了改进建议。对分布管的腐蚀形貌观察、材质分析、成分分析、介质分析和工艺操作分析结果表明,塔顶物料的高速冲刷造成了冲刷腐蚀,氯离子对奥氏体不锈钢的点蚀造成了金属表面钝化膜的破坏,加剧了冲刷腐蚀;提出了升级顶回流分布管材质、控制顶回流进料量、回用净化水改去污水处理厂处理等改进措施。

The cause analysis was made regarding the corrosion problems of the top reflux distribution pipe and gas hole top plate at the top of the sour water stripper, and improvement suggestions were put forward. Through the observation on the corrosion morphology of the distribution pipe, material analysis, component analysis, medium analysis and process operation analysis, it was found that the high-speed scouring of tower top materials led to the erosion corrosion, and the chloride ion pitting corrosion on austenitic stainless steel caused the destruction of passive film on the metal surface, which further exacerbated the erosion corrosion. The improvement measures were proposed, such as upgrading the material of top reflux distribution pipe, controlling the feed rate of top reflux, and changing the purified water treatment to the sewage treatment unit.