火电厂输灰埋地管道腐蚀爆管试验

Experimental research on the tube explosion caused by corrosion of ash-transporting buried pipelines in power plant

针对某电厂埋地钢质浓灰管道外壁产生严重腐蚀穿孔并频繁发生泄露的问题进行了分析,并采用PCM(多频管中电流检测法)进行了管道外防腐层的质量评估及外防腐层的漏点检查,找出了管道腐蚀的主要原因:外防腐层破损点较多、土壤腐蚀性强、外部腐蚀电流进入、管道之间有电连接从而形成电偶腐蚀等多个因素共同作用,最终导致管道的严重腐蚀泄漏。提出了对腐蚀最为严重的部分管道进行开挖,对钢管及防腐层进行修补,部分管线进行阴极保护的处理措施。经过3 a的运行检验,长60 km的埋地管道没再发生爆管。

The problem of serious corrosion perforation and frequently occurred leakage happened on the outer surface of a buried steel ash-transporting pipelines in a power plant was analyzed. The leakage points of the pipeline external anti-corrosion layer were checked and the quality evaluation was carried out by means of PCM （Current Monitoring Method in Multi-frequency Pipeline）. The main reason of pipeline corrosion was found out, which is mass of damage points on the outer anti-corrosion layer, the strong corrosion of the soil, the entrance of the external corrosion current, the galvanic corrosion caused by electrical connections among pipelines and so on. The combined action of these factors will finally lead to heavy corrosion leakage. The excavation was carried out to the most serious corrosion part of pipelines, the patching to steel pipeline and anti-corrosion layer was carried out, and cathodic protection treatment measures were used on parts of pipeline. Through the operation test, none tube explosion happened on the 60 km buried pipelines in the last three years.