吸收氧化塔腐蚀机理分析及防腐策略  

Analysis of corrosion mechanism and anti-corrosion strategy for absorption oxidation tower

作　　者：秦雪源[1] 何巍杨 刘勇[1] 肖淑国[1] QIN Xueyuan;HE Weiyang;LIU Yong;XIAO Shuguo(Northwest Oilfield Branch of China Petroleum and Chemical Corporation,Urumqi 830011,China;School of Mechanical Engineering,Xinjiang University,Urumqi 830017,China)

机构地区：[1]中国石油化工股份有限公司西北油田分公司,乌鲁木齐830011 [2]新疆大学机械工程学院,乌鲁木齐830017

出　　处：《压力容器》2024年第8期56-63,88,共9页Pressure Vessel Technology

基　　金：中石化重点科研项目(319016-5)。

摘　　要：为探索吸收氧化塔内壁、内部附属管件严重腐蚀的本质原因,通过材质分析、宏观形貌观察、腐蚀产物表征分析、脱盐水和药剂检测、运行参数分析、模拟试验分析手段对腐蚀机理进行分析。结果表明:所有材质符合国标要求;塔内溶液中Cl^(-)浓度(254 mg/L)偏高,脱盐水和塔内溶液中存在较高含量的溶解氧(7.5 mg/L),同时溶液中还存在残留的H_(2)S(停产期间持续通入);腐蚀产物EDS测试结果显示,腐蚀部位发生一定的化学反应。综合分析得出造成腐蚀的主要原因为Cl^(-)吸附在金属表面缺陷处,致使氧化膜难以修复,在高含量氧条件下,氧与不锈钢基体发生反应,基体开始溶解,未完全吸收的H_(2)S导致不锈钢表面氧化膜发生硫化,致密性下降,又在停运期间FeCl_(3)溶液作用下,点蚀进一步发展成为稳态的点蚀坑,形成腐蚀。该研究结果为同类型装置腐蚀原因提供了排查方向,对装置防腐提供了具体参考措施,避免了造成装置腐蚀的严重后果。To explore the fundamental causes for severe corrosion of the inner walls and internal accessory fittings of the absorption oxidation tower,the corrosion mechanism was analyzed through material analysis,macroscopic morphology observation,corrosion product characterization analysis,desalinated water and chemical detection,operating parameter analysis,and simulation experiment analysis.The results show that all materials meet the requirements of national standards;The concentration of CLin the solution inside the tower is relatively high(254 mg/L),and there is a high content of dissolved oxygen(7.5 mg/L)in the desalinated water and the solution inside the tower.At the same time,there is also residual H_(2)S in the solution(which is continuously introduced during the shutdown period);The EDS test results of corrosion products show that a certain chemical reaction occurs at the corrosion site.In summary,the main cause of corrosion is the adsorption of chloride ions on metal surface defects,making it difficult to repair the oxide film.Under high oxygen content conditions,oxygen reacts with the stainless steel substrate,causing the substrate to dissolve.Incomplete absorption of H_(2)S leads to sulfidation of the oxide film on the stainless steel surface,resulting in a decrease in density.During the shutdown period,under the action of FeCl_(3)solution,the pitting corrosion further develops into a steady-state pitting corrosion pit,forming corrosion.The research results provide a direction for the investigation of the causes of corrosion of the same type of device,and provide specific reference measures for the anti-corrosion of the device,so as to avoid the serious consequences of device corrosion.

关 键 词：吸收氧化塔 腐蚀机理 形貌分析 防腐策略 

分 类 号：TH49[机械工程—机械制造及自动化] TQ053.5[化学工程] TQ050.9