不同腐蚀环境下压力容器材质耐蚀性评价

结合塔河油田实际情况,通过对压力容器拟选用的5种材料20、20G、Q345、A333、Q245分别进行CO_2+H_2S共同控制环境、H_2S主控腐蚀环境和CO_2主控腐蚀环境3个环境下的腐蚀失重试验,并对经过试验的挂片进行扫描电镜(SEM)观察和能谱(EDS)分析。结果显示:选取的5种材质的挂片在CO_2+H_2S共同控制环境和H_2S主控腐蚀环境的腐蚀速率均小于0.1 mm/a,且比CO_2主控腐蚀环境条件下的腐蚀速率小;在H_2S+CO_2共同控制的腐蚀环境中,5种材质腐蚀速率大小依次为Q345>20>Q245>A333>20G;在H_2S腐蚀为主的环境中,5种材质腐蚀速率大小依次为20>20G>Q245>Q345>A333;在CO_2腐蚀为主的环境中,5种材质腐蚀速率大小依次为Q345>A333>20G>20>Q245。根据试验结果,不同腐蚀环境下5种材料的防腐蚀性能均不同,结合现场实际工况,对压力容器材质进行相应的选材。

Evaluation of Corrosion Resistance of Pressure Vessel Materials under Different Corrosive Environments

According to the actual situation in Tahe oilfield,five kinds of materials( 20,20 G,Q345,A333 and Q245) were studied under the CO2+H2S coexistence corrosion environment,the H2S corrosion environment and the CO2 corrosion environment,respectively. The plate samples after hanging test were analyzed by scanning electron microscope( SEM) and energy dispersive spectrometer( EDS). Results showed that the corrosion rates of the five materials were all less than 0.1 mm/a in the coexistent environment of CO2+H2S and in the environment of H2S,which was less than that in the corrosion environment of CO2. In the corrosion environment controlled by H2S and CO2,the corrosion rates were Q345>20>Q245>A333>20 G. In the corrosion environment controlled by H2S,the corrosion rates were 20> 20 G>Q245>Q345>A333. In the corrosive environment controlled by CO2,the corrosion rates were Q345>A333>20 G>20> Q245. According to the above results,the anti-corrosion property of the five materials was different under different corrosion conditions. Therefore,the pressure vessel material should be selected according to the actual conditions of the field.