站内工艺管网局部腐蚀分析

Analysis on Local Corrosion in Plant Piping.

随着输油管道及设备的不断老化,站内工艺管网的局部腐蚀日益严重,通过重点抽样调查,总结了站内管网局部腐蚀的多发部位为:埋地管段的底部、地沟管段、架空管段、穿墙管段的伴热线附近、管段的支撑架接触区、保温管段的上部及压力表接头等。造成管道易发生腐蚀的原因有:土壤腐蚀、点蚀、缝隙腐蚀、浓差电池腐蚀、微电池腐蚀等多种类型。针对上述的腐蚀可采用对站内工艺管网进行阴极保护,缓蚀剂防止局部腐蚀破坏,改变管段周围的腐蚀介质,选择有效的防水层和防腐层,加强维护管理等措施。

Local Corrosion occurs in plant piping when oil pipeline and equipment are aging with time. Through sampling investigation, the following positions are recognized where local corrosion is most likely to occur: the bottom of hurried pipes through wall, contacting areas between pipe and its support, the connection between insulated pipe and pressure guage, etc. Local corrosion results from soil corrosion, spot corrosion, crevice corrosion, concentration cell corrosion, micro-cell corrosion, etc. Such measures against the said corrosion are taken as CP system, corrosion inhibitor, correct surrounding medium for pipe, effective corrosion/water proof layer, and internal corrosion prevention.