某焦化厂脱硫脱硝系统空冷管穿管原因及预防措施  

Causes of Perforation of Air-Cooled Tubes in Desulfurization and Denitrification System in a Coking Plant and Its Preventive Measures

作　　者：董登超 张继明 邵久刚 石丽丽 DONG Dengchao;ZHANG Jiming;SHAO Jiugang;SHI Lili(Institute of Research of Iron and Steel,Shagang,Jiangsu Province,Co.,Ltd.,Zhangjiagang 215625,China)

机构地区：[1]江苏省(沙钢)钢铁研究院,张家港215625

出　　处：《腐蚀与防护》2023年第9期107-112,共6页Corrosion & Protection

摘　　要：采用金相显微镜、扫描电镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD)等方法,分析了某焦化厂脱硫脱硝系统空冷管穿管的原因。结果表明:由于含有水汽的高温烟气在空冷管外壁产生冷凝水,烟气中SO_(2)、SO_(3)、O_(2)和Cl^(-)等腐蚀介质发生溶解,含有腐蚀性介质的冷凝水渗入,并在空冷管基体与搪瓷层界面处积存,空冷管基体发生腐蚀,生成较为单一的腐蚀产物α-FeOOH,α-FeOOH为多孔结构,附着在空冷管基体表面,使腐蚀介质在搪瓷层与基体界面富集,加速了腐蚀的扩展和空冷管壁减薄,最终导致穿管。The causes of perforation of air-cooled tubes in desulfurization and denitrification system in a coking plant were analyzed by means of metallographic microscope,scanning electron microscope(SEM),energy dispersive spectrometer(EDS) and X-ray diffractometer(XRD).The results showed that the high-temperature flue gas containing water vapor generated condensate water on the outer wall of the air-cooled tube,and the corrosive media such as SO_(2),SO_3,O_(2) and Cl~- in the flue gas was dissolved.The condensate water containing corrosive media infiltrated and accumulated at the interface between the air-cooled tube substrate and the enamel layer.The air-cooled tube substrate was corroded to form a relatively single corrosion product α-FeOOH.The α-FeOOH had a porous structure and was attached to the surface of the air-cooled tube substrate,so that the corrosive medium was enriched at the interface between the enamel layer and the substrate,which accelerated the expansion of corrosion and the thinning of the air-cooled tube wall,eventually leading to the penetration of the tube.

关 键 词：脱硫脱硝 空冷管 Α-FEOOH 电化学腐蚀 不锈钢 

分 类 号：TG172[金属学及工艺—金属表面处理]