脱硫装置用316L不锈钢管道泄漏原因分析  

Leakage Cause Analysis of 316L Stainless Steel Pipeline used in Desulfurization Device

作　　者：刘成[1] LIU Cheng(Shanghai Environmental Engineering Technology Branch of Energy Development Co.,Ltd.,CNOOC)

机构地区：[1]中海油能源发展股份有限公司上海环境工程技术分公司

出　　处：《油气田地面工程》2020年第11期87-91,共5页Oil-Gas Field Surface Engineering

摘　　要：某热电厂内氨法烟气脱硫装置采用316L不锈钢管道,在运行3个月后发生泄漏失效。通过直读光谱仪、光学显微镜、扫描电子显微镜(SEM)和X射线衍射仪(XRD)等技术手段,对失效管道的化学成分、显微组织及腐蚀产物进行了分析;采用pH计和滴定法,对管道内水介质的pH值和相关组分含量进行了检测;采用动电位极化法测定了316L不锈钢在管道内水介质中的临界点蚀温度。结果表明:该316L不锈钢管道的泄漏失效原因主要是管道中水介质的Cl-含量超过了其临界范围,引起材料点蚀穿孔;另外,水介质的运行温度超过了临界点蚀温度,促进了点蚀的发生和发展。可通过控制介质中Cl-含量、降低管道运行温度或选用耐蚀性更高的材料等措施延长管道的使用寿命。The 316L stainless steel pipeline used in ammonia flue gas desulfurization unit in a thermal power plant has leakage failure after 3 months of operation.By means of direct reading spectrometer,optical microscope,scanning electron microscope(SEM),and X-ray diffractometer(XRD),the chemical composition,microstructure,and corrosion products of the failed pipeline are analyzed.The pH value and relevant component content of the water medium in the pipeline are tested by means of pH meter and titration.The critical point corrosion temperature of 316L stainless steel in water medium is determined by the potentiometric polarization method.The results show that the leakage failure of the 316L stainless steel pipe is mainly caused by the fact that the Cl-content of the water medium in the pipe exceeds its critical range,which leads to pitting and perforation of the material.In addition,the operating temperature of the water medium exceeds the critical corrosion temperature,which promotes the occurrence and development of pitting.The service life of the pipeline could be extended by controlling Cl-content in the medium,reducing the operating temperature of the pipeline,or selecting materials with higher corrosion resistance.

关 键 词：316L不锈钢管道 氨法脱硫 点蚀 CL-含量 运行温度 耐蚀材料 

分 类 号：X773[环境科学与工程—环境工程] TM621[电气工程—电力系统及自动化]