一种少见的阴极保护系统失效情况分析

A Rare Failure Case Analysis of Cathodic Protection System

北京某热电厂输油管道为硬质聚氨酯泡沫塑料保温层外加高密度聚乙烯夹克层的保温管道。为了摸清该管道现行阴极保护系统的运行状况,通过测量牺牲阳极的开路电位、输出电流和管道保护电位等参数,证实该管道阴极保护没有起到应有的作用。文章分析了该阴极保护系统失效的原因,提出了改进建议。其一,此类防腐结构的管道可以不采用阴极保护;其二,在设计和安装阴极保护系统时应对相邻管道的影响予以充分重视。

The oil transmission pipeline of a thermoelectric plant in Beijing is an insulation pipeline, which consists of a rigid PU foam thermal insulation layer with a high density PE jacket. In order to understand clearly the working status of a current cathodic protection system, the related parameters such as open circuit potential, output current and pipeline protection potential were tested. The test results shows the cathodic protection system of the pipeline does dot function as expected. After analyzing the reason of functional failure of the cathodic protection system, the corresponding improvements are suggested, which include: (1) pipeline with such insulation structure may not apply cathodic protection; (2) in design and installation of cathodic protection system, the effect of adjacent pipeline on cathodic protection should be paid more attention to.