Common Defects and Protection Countermeasures of Cathodic Protection for Long-distance Natural Gas Steel Pipeline

Common Defects of Cathodic Protection for Long-Distance Natural Gas Steel Pipelines

After a long period of operation, many problems have arisen in the application of cathodic protection systems for long-distance natural gas steel pipelines. On the one hand, the cathodic protection equipment is old and aging, and can no longer operate normally. The reason for this problem is that the potentiostat adjustment switch at the first station of the long-distance natural gas steel pipeline fails due to time problems, and the protection potential cannot be adjusted. The potentiostat converter at the end station cannot perform the efficient conversion, resulting in output from the machine, but no output from the steel pipeline. The high resistance of the anode ground bed has a great impact on the divergence of the cathode current, and the sacrifice of the anode cannot play its due role, which leads to the loss of protection of most steel pipelines and serious corrosion. On the other hand, the protection potential of the steel pipeline is too high, causing serious corrosion of some steel pipeline sections. At this stage, the potential of most long-distance natural gas steel pipelines is in a relatively high state, and the steel pipeline protection potential deviates from the normal potential, which in turn aggravates steel pipeline corrosion.

Countermeasures for improving cathodic protection of long-distance natural gas steel pipelines

In the natural gas steel pipeline cathodic protection process, the first method to be selected is the steel pipeline cathodic protection method. Since long-distance natural gas steel pipelines usually use sacrificial anodes and forced current cathodic protection for steel pipeline anticorrosion, at this time, the buried depth of steel pipelines and sacrificial anodes is usually kept within the range of 2m to 2.5m, but for long-distance natural gas steel pipelines At the same time, due to the natural landform, many steel pipelines have a serious drop at both ends. At the same time, the groundwater level at both ends of the steel pipeline is different from the geological conditions, and the resistivity of the soil where some steel pipelines are located is too high. , the efficiency of the cathodic protection method using sacrificial anodes in this area is not high. The way to solve this problem is to change the sacrificial anode protection method to forced current protection for the high soil resistivity section steel pipelines in the long-distance steel pipeline process Law. Secondly, the potentiostat can provide continuously adjustable cathodic protection current to the metal body to be protected during the application of the forced current method. It provides an auxiliary function to the anode in the forced current method and is used to make the cathodic protection current provided by the potentiostat form a loop. Finally, in the actual cathodic protection process of long-distance natural gas steel pipelines, a professional team with a strong sense of responsibility can be created, and the principle of fixed positions and responsibilities can be adopted for management. Cathodic protection of long-distance natural gas steel pipelines.