社区燃气管道腐蚀热点现场测试与特征识别浅析

Preliminary Analysis on On-Site Test and Feature Recognition of Corrosion Hotspots in Community Gas Pipelines

由于城市燃气管道服役环境日益复杂,社区燃气管道的泄漏事件频繁发生,因此,有效识别社区燃气管道腐蚀的热点区域,对于社区燃气管道安全运行至关重要。在A、B、C 3个社区开展了现场测试与试验,测试了A、B、C 3个社区管道的试片通、断电电位、试片电流密度、地电位梯度以及土壤电阻率等服役参数,采用XRD分析了与A社区管道相连的极化检查片腐蚀产物的成分,并对A社区的燃气管道与周围钢质结构进行了电连接性测试。结果表明:A、B、C社区燃气管道均存在管地电位明显偏正的现象,且通电管地电位明显正于断电电位,有电流稳定流出。A社区管道的极化检查片的腐蚀产物主要是Fe_(3)O_(4)、SiO_(2)和Fe_(2)MgO_(4),其中SiO_(2)主要来自于极化检查片表面的泥土。A社区燃气管道与周围钢结构物存在电连接,从而加速了管道腐蚀。

Due to the increasingly complex environment of urban gas pipeline service, community gas pipeline leakage events occur frequently, so, effective identification of hot spots for corrosion in community gas pipelines is crucial for the safe operation of community gas pipelines. In this paper, field tests and experiments were carried out in communities A, B and C, and service parameters such as test piece power-on/off potential, test piece current density, ground potential gradient, and soil resistivity of pipelines in communities A, B and C were tested, and the corrosion products of the polarization inspection piece connected to the community A pipeline were analyzed by XRD. Besides, the electrical connectivity between the gas pipeline and the surrounding steel structures in community A was tested. Results showed that the gas pipelines in communities A, B and C all had a significant positive pipe-to-soil potential, the power-on pipe-to-soil potential was significantly positive compared to the power-off potential, and there was a steady current outflow. The corrosion products of the polarization inspection piece of the pipeline in community A were mainly Fe_(3)O_(4), SiO_(2) and Fe_(2)MgO_(4), in which SiO_(2) mainly came from the soil on the surface of the polarization inspection piece. In addition, there existed the electrical connection between the gas pipeline in community A and the surrounding steel structures, which accelerated the corrosion of the pipeline.