转炉煤气柜柜内钢结构的腐蚀原因

摘要

The corrosion reason and mechanism of a steel strusture inside a converter gas lolder were discussed through the analysis of corrosive medium and corrosion products.The results show that the corrosion products were mainly composed of FeCO3,CaCO3 and a little of iron oxides.In addition,the gas condensate in the gas holder contained a lot of corrosive ions,such as HCO3-,Cl-.When the gas condensate had formed a layer of liquid film on the carbon steel surface,homogeneous corrosion of CO2 on the carbon steel surface in the gas holder occurred.The corrosive irons,such as Cl-and O2,could penetrate through the corrosion product films and the corrosion of carbon steel was accelerated,which could cause lots of corrosive pits on the surface of carbon steel in the gas holder.%对转炉煤气柜内腐蚀介质与腐蚀产物进行分析,探讨了柜内钢结构腐蚀的原因与机理.结果表明:柜内碳钢表面腐蚀产物主要由FeCO3及少量铁氧化物和CaCO3组成,煤气冷凝水中含有大量的HCO3-及Cl-等腐蚀性离子,因此气柜内钢结构腐蚀主要是由CO2引起的,CO2溶于冷凝水后,在碳钢表面形成一层弱酸性腐蚀液膜,使得钢结构表面发生了CO2均匀腐蚀.由于柜内煤气温度较低,形成的腐蚀产物疏松,使得氧气、Cl-等能渗透到碳钢表面,加速局部腐蚀,使得气柜侧壁及底板表面出现许多腐蚀孔洞.