Effect of Temperature on Corrosion of Pipeline Steel in SRB/CO2 Environment

The present work explored the effect of temperature on its corrosion performance, and investigated the corrosion characteristics of X65 pipeline steel in sulfate reducing bacteria (SRB)/ saturated CO2 environment. Immersion and electrochemical tests were conducted on X65 pipeline steel at three temperature levels of 20 ℃, 40 ℃, and 60 ℃. The changes in SRB in the solution at high temperature were detected through 16S rRNA gene sequencing, and the surface morphology and pitting characteristics after corrosion were observed. The results showed that as temperature of the solution increased, SRB metabolism accelerated. Thermophilic SRB preferentially proliferated at high temperatures, and together with other thermophilic bacteria that produce S2-, it accelerated the generation of S2-, promoting the transition of S from an oxidizing state to a reducing state, and depositing it in corrosion products. At 40 ℃, the number of SRBs was the highest and the pitting rate was the highest, which could be attributed to the adsorption of SRBs on the surface of the sample. In the adsorption area of the SRB community, the reduction effect on the sample surface was enhanced, local cathodic reactions were accelerated too, and corrosion pores were generated. At 60 ℃, the uniform corrosion rate was the highest, the ion mass transfer was accelerated, and the thermophilic SRB genus largely proliferated. The combined action of microorganisms and CO2 caused severe uniform corrosion. © 2024 Cailiao Daobaoshe/ Materials Review. All rights reserved.