城市在役旧煤气管道的阴极保护研究及实践

Cathodic Protection Practice of Used Urban Gas Pipeline in Service

城市管道地下环境复杂,拟采用牺牲阳极法对一条城市在役管道主线实施阴极保护,采用变频选频法和分段馈电试验法获得了管道的保护电流密度等重要参数,并探讨分析了影响城市旧煤气管道保护电流密度设计的某些因素。最终方案中阴极电流密度分别为0.65～1.00mA/m2(武汉市中北路),1.50～3.00mA/m2(武汉市徐东路),2.50～3.00mA/m2(武汉市团结路至团结一路),影响电流密度的因素有管线腐蚀状况、土壤腐蚀性及阀门井数量。该方案成功地实施于工程中。

It is imperative to protect the urban pipelines working under complex underground surrounding. Thus sacrificial anode method was tried to realize cathodic protection for the used main pipelines in urban service. The major parameters including protection current density for the cathodic protection of the pipelines were determined making use of frequency-conversion/frequency-selection method and power feeding test. The factors affecting the design of the protection current density of the used gas pipelines were discussed. As the results, the cathodic protection could be successfully used for the protection of the urban gas pipelines. The factors affecting the current density included the corrosion situation of the used pipelines, the corrosiveness of the soil, and the number of the valve well. The cathodic protection current density was suggested as 0.65~1.00 mA/m^2 for the pipelines on Zhongbei Road, 1.50~ 3.00 mA/m^2 for the pipielines on Xudong Road, and 2.50~ 3.00 mA/m^2 for those from the Unity Road to No.1 Unity Road.