海水管道内壁外加电流系统棒状辅助阳极保护距离探讨

目的研究不同管径海水管道在静态及不同海水流速环境中外加电流系统棒状辅助阳极对管道内部腐蚀防护的规律。方法模拟海水管道实海环境,对管道施加棒状辅助阳极外加电流阴极保护,连续测定管道不同部位保护电位,由此得到防护规律。结果静态试验中,随管径变小,最大保护距离越短,当管径直径≤100 mm时,棒状辅助阳极基本起不到保护作用,不适宜用此种方法保护。动态试验中,同一管径的管道,流速越大,保护效果越差,但影响不大,流速在2~4 m/s之间保护距离差异不大;不同管径,仍如静态实验结果相似,随管径变小,保护距离越短。结论棒状辅助阳极在海水管道中的保护距离有限,且不适合小管径管道,要想提供管道长距离稳定的保护效果需考虑其他方式。

Protection Distance of Impressed Current System Rod-shaped Auxiliary Anode in Seawater Pipe

Objective To study corrosion protection rules of impressed current system bar-shaped auxiliary anode in different diameter seawater pipes based on the static and dynamic environments. Methods The marine environment of seawater pipes were simulated, the seawater pipe was protected with rod-shaped auxiliary anode and cathode and the protection potential on different position of the pipe was measured to obtain the rules of corrosion protection. Results In static test, the smaller the diameter, the shorter the maximum protection distance. When the pipe diameter was less than or equal to 100 mm, the rod-shaped anode almost did not work. This protection method was unsuitable. In dynamic test, in case the pipes of the same diameter, the greater the flow velocity, the worse the protection effect. But the influence was not significant. There was little different in protection distance when the flow velocity was between 2 m/s and 4m/s; in case of different pipe diameter, the result was also similar to that of static test. The smaller the diameter, the shorter the protection distance. Conclusion The protection distance of rod-shaped auxiliary anode is limited, and it is unsuitable for small diameter pipes. It needs to consider other ways to provide uniform protection effect of long distance for pipe.