Failure analysis of CO2 corrosion of natural gas pipeline under flowing conditions

Abstract

The CO2 corrosion mechanism of pipelines is a controversial topic, especially under flowing conditions. In this work, the CO2 corrosion behavior of X80 steel under static and flowing conditions was studied by the electrochemical measurement and computational fluid dynamics (CFD). The results showed the CO2 corrosion was controlled by charge transfer in static conditions and mass transfer in flowing conditions. Localized damage of corrosion product film under flowing conditions is caused by CO2 bubble cavitation rather than wall shear. The failure process under flowing conditions can be divided into three stages: localized corrosion, bubble cavitation-film rupture and enhanced localized corrosion. The corrosion behaviors of CO2 under static and flowing conditions were described, and the corrosion mechanism was expounded.