H_2S对碳钢在模拟罐底水中腐蚀行为的影响

Effects of H_2S on Corrosion Behavior of Carbon Steel in Simulated Oil Storage Tank Bottom Solution

利用腐蚀失重法、电化学测试、扫描电镜(SEM)和X射线衍射(XRD)研究了Q235碳钢在含H_2S的模拟罐底水中的腐蚀行为。结果表明:增加H_2S含量,可以促进碳钢表面的析氢反应,从而增大了碳钢的腐蚀速率;碳钢表面形成由四方硫化亚铁组成的疏松、多孔的腐蚀产物膜;碳钢先后在含H_2S溶液、无H_2S且含溶解氧的溶液中进行二次腐蚀后,其腐蚀产物分为两层,内层主要组成依然是四方硫化亚铁,外层为氧化产物,其中氧化产物的生成导致硫化亚铁膜的破裂与脱落;硫化亚铁膜的存在,对碳钢在含H_2S溶液中的保护性大于其在含溶解氧溶液中的。

The corrosion behavior of Q235 carbon steel in simulated solution containing H2S was investigated using the methods of weight loss, electrochemical measurement, scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The results show that the increase of H2S concentration promoted hydrogen evolution reaction, so the corrosion rate of carbon steel increased. The loose and porous corrosion products formed on the steel surface were composed of mackinawite. The corrosion products of carbon steel, which was corroded in sequence in the solution containing H2S and in the solution containing dissolved oxygen but without H2S, were divided into two layers. The inner layer was still mainly composed of mackinawite and the outer layer was oxidation product. The oxidation product led to the rupture and shedding of ferrous sulfide film. The existence of ferrous sulfide film provided more protection to carbon steel in the solution containing H2S than in the solution containing oxygen.