油田污水中碳钢表面生物膜生长规律及腐蚀电化学行为  

Evolution of SRB Biofilm and Its Influence on Corrosion of Q235 Carbon Steel in Oilfield Sewage

作　　者：叶琴[1] 李克娟[1] 郭佩佩[1] 刘宏芳[1] 

机构地区：[1]华中科技大学化学与化工学院,武汉430074

出　　处：《腐蚀科学与防护技术》2013年第3期195-201,共7页Corrosion Science and Protection Technology

基　　金：国家自然科学基金(51171067);深圳市基础研发基金(JC201005310696A)资助

摘　　要：采用环境扫描电镜(ESEM)、能谱分析仪(EDS)、X射线衍射仪(XRD)、自腐蚀电位与电化学阻抗谱方法,研究了胜利油田集输管线系统污水中碳钢生物膜生长特性及管线材料的腐蚀行为。结果表明,在碳钢表面首先形成铁氧化物;随着生物膜的形成逐步转变成致密硫化亚铁,即腐蚀产物的内层;随后,生物膜在第8 d趋于成熟,大量含碳胞外聚合物组成疏松外层膜,至第11 d部分生物膜脱落造成基体表面有裸露点蚀坑出现。电化学数据表明,随着生物膜层逐渐致密,碳钢电极容抗弧变大,第11 d由于生物膜脱落,电荷传质电阻迅速减小,腐蚀加速,后期高频容抗弧消失,生物矿化产物增加了生物膜的扩散阻力,出现扩散控制,且部分生物膜脱落,局部腐蚀加剧。A comparative study about growth characteristics of biofilm on the surface of Q235 carbon steel immersed in sewage from the gathering transportation pipeline of Shenli oilfield, was performed by using environmental scanning electron microscope （ESEM）, energy disperse spectroscop （EDS）, X-ray diffraction （XRD）, while its influence on the corrosion behavior of the carbon steel was also examined by means of open circuit potential （OCP） and electrochemical impedance spectroscop （EIS）. The results showed that a film of iron oxides formed in the initial stage of immersion. As the biofilm matured, the initial iron oxides were gradually converted to iron sulphides, to be a dense inner layer of the corrosion products scale, then numerous extracellular polymeric substances （EPS） containing carbohydrate appeared in the mature biofilm on the 84 day. As a result of exfoliation of the films after 11 d immersion, pits octa＇red on the surface. EIS data revealed that corrosion resistance of the steel increased while the dense biofilm formed on the surface. The charge transfer resistance/Lt decreased dramatically on the 11th day was ascribed to the protective film cracked and thereby the corrosion was enhanced. During the later immersion period, a Warburg diffusion slope appeared at low frequency region instead of initial semicircle athigh frequency region, which revealed that mineralization products might induce the increment of the diffusion barrier of the biofilms. In the meawhile, localized corrosion was activated due to the exfoliation of the biofilm.

关 键 词：集输管线 Q235碳钢 生物膜 硫酸盐还原菌 电化学阻抗谱 

分 类 号：TG172[金属学及工艺—金属表面处理]