Corrosion Behavior of 2205 DSS in Sulfate Reducing Bacteria and Ferro Bacteria Microbial Environment

Abstract

Aiming at the problem of bacterial corrosion in the gathering and transportation pipeline of shale gas field, the corrosion behavior of 2205 DSS in sterile and bacteria-bearing simulated media [Containing 2.5×104/mL sulfate reducing bacteria(SRB) and 6.0×103/mL ferro bacteria(FB)] was compared and studied by means of SEM, EDS, AFM and electrochemical analysis. Results showed that the pitting of 2205 DSS occurred in both environments, but the pitting of the sample in simulated water with bacteria was more serious. There were many dispersed attachments of elements such as Fe, O and S on the surface of samples corroded by simulated media with bacteria. Impedance analysis showed that the passivated film on the surface of the sample was vulcanized under the influence of microorganisms, resulting in a decrease in polarization resistance. Moreover, the polarization curve analysis showed that the corrosion potential of the sample decreased under the influence of microorganisms, indicating that its corrosion resistance decreased. Through the analysis of experimental results, the corrosion mechanism of 2205 DSS in the shale gas transmission environment was: when there was residual oxygen in the early stage, it was mainly the activity of FB that produced an anaerobic environment rich in iron; later, SRB proliferated in the anaerobic zone under the action of Cl-, producing sulfide precipitation, which intensified the corrosion of stainless steel.

Keywords

• shale gas gathering and transportation pipeline；2205 dss；bacterial corrosion；srb；fb