Corrosion of buried gas pipelines

Thread Content

Gas pipelines are often laid in harsh geological conditions, and due to impurities in the gas, severe corrosion occurs on the inner walls of certain sections of these pipelines, creating a safety risk of sudden gas leaks. Due to the unpredictability of localized corrosion in gas pipelines, it is a major cause of pipeline accidents. Generally, the factors that lead to localized corrosion in gas pipelines include the geological environment as well as the material of the pipeline and its manufacturing process. In underground conditions, gas pipelines are primarily corroded by bacteria, soil, and stray currents. The secondary induced alternating current generated near the pipeline overlaps with the destructive current produced by the pipeline, resulting in stray current corrosion. The amount of corrosion is small, but the degree of localized corrosion is high. Furthermore, sulfate-reducing bacteria in the soil reduce soluble sulfates to hydrogen sulfide and iron, resulting in bacterial corrosion. The material composition and manufacturing factors of pipeline steel are the internal causes of pipeline corrosion; in particular, the chemical composition of pipeline steel along with its numerous microcrystals lead to severe corrosion problems.