Influence of operation of Kh52 steel on corrosion processes in a model solution of gas condensate

We investigate the corrosion and electrochemical properties of Kh52 steel in the initial state and after 30 years of operation in main gas pipelines. It is established that the behavior of the steel in a model medium of aqueous condensate is intensified due to a high concentration of chloride depassivators. The corrosion rate is controlled by the diffusion of cathodic depolarizers, mainly hydrocarbonate ions. In the static medium of water condensate, no influence of the long operation of Kh52 steel on its corrosion resistance was found, which is due to the shielding action of a layer of corrosion products. The corrosion rate of the steel of the operated pipes is substantially higher than that of the initial steel in a dynamic medium, but the corrosion mechanism is the same. The decrease in the corrosion resistance of the operated steels is caused by the intensification of the reaction of their anodic dissolution. For assessing the influence of in-service degradation of a steel on its corrosion properties, we recommend carrying out corrosion investigations with vigorous stirring of the working medium.