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

Abstract

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 Fe3O4，SiO2and Fe2MgO4，in which SiO2mainly 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.

Keywords

• community gas pipeline|corrosion hot spot|field test|feature recognition|electrical connection