Sulfate-reducing Bacteria On The Corrosion Behavior Of The Buried Gas Pipeline

The sulfate-reducing bacteria is a kind of disgust oxygen, it can accelerate corrosion rate of the undergroud gas pipeline,it is an important factor that cause undergroud gas pipeline to be decayed partly, which can cause undergroud gas pipeline to explode and reveal affairs. In this paper, we selected especially soil in Gui Zhou. The effects of SRB on the corrosion behavior of underground gas pipeline were investigated by electrochemical impedance spectroscopy(EIS), polarization curve, scan-ing electron microscope(SEM), Energy dispersive spectroscopy (EDS), weight loss. what we do and the main conclusion as follows:(1) The effects of SRB on the corrosion behavior of underground gas pipeline. As a result: SRB accelerated corrosion rate of the underground gas pipeline. the average corrosion rate of underground gas pipeline in soil with SRB as larger as 2. 2 times than that in soil without SRB, but pitting rate in soil with SRB as larger 6 times than that in soil without SRB.(2)SRB influenced the corrosion of undergroud gas pipeline in different soil humidity. The results showed as follows: The humidity obviously influenced the corrosion behavior of undergroud gas pipeline when soil with SRB. With humidity increasing, the number of SRB would add;average corrosion rate and pitting rate of the underground gas pipeline would increase. Average corrosion rate reached a peak value when water content was about 20%-25%. In contrast, pitting rate reached a peak value when water content was about 15%-20%. average corrosion rate was as larger as 10 times than the pitting rate.(3) cathode protection influenced the corrosion of undergroud gas pipeline when the soil with SRB. the result showed:with the increasing of applied cathodic potential, the pH of soil gradually increased, the number of SRB and corrosion rate of the underground gas pipeline would decrease, and cathodic protection efficiency would increase. At the same cathodic pote- ntial, the corrosion rate of underground gas pipeline in soil with SRB was obviously larger than that in soil without SRB. When cathode potential reached -1150 mV, corrosion rate of the underground gas pipeline would increase and cathodic protection efficiency would decrease. In order to control SRB destroy underground gas pipeline, The best cathodic potential of the underground gas pipeline in soil without SRB should select -950mV, but the best cathodic potential of the underground gas pipeline in soil with SRB should select -1050mV.