FV(520)B不锈钢在CO_2/H_2S共存条件下的腐蚀行为

Corrosion Behavior of FV(520)B Stainless Steel in the Co-existence of CO_2 and H_2S

目的研究长输管线压缩机叶片材料FV(520)B不锈钢在高含H_2S、H_2O、CO_2条件下的腐蚀行为。方法利用高温高压反应釜模拟特定工况,在H_2S分压为0.9 MPa、CO_2分压为0.6 MPa、温度为150℃的条件下于5 g/L的氯化钠溶液中制备硫化腐蚀层,利用XPS、SEM、XRD等手段对腐蚀层的成分及结构进行分析。结果 FV(520)B不锈钢的腐蚀速率逐渐降低,试样表面粗糙度先增大后下降,腐蚀产物主要为FeCO_3、Fe_3O_4、FeS、FeS_2、S、Cr_2S_3、Cr_2O_3和Cr(OH)_3。结论在腐蚀前期,FeS的形成速率大于FeS_2、S,腐蚀产物颗粒不断长大。形成完整的Cr_2O_3、Cr(OH)_3保护膜后,腐蚀得到抑制,此时腐蚀反应主要为FeS_2、S的生成,试样表面腐蚀产物颗粒尺寸变小,试样表面粗糙度降低。

Objective To study the corrosion behavior of the blade material FV（520）B stainless steel of long pipeline com- pressor under special working conditions containing high H2S, H2O and CO2. Methods A high temperature and high pressure reaction kettle was used to simulate the specific working conditions. FV（520）B specimen was put in 5 g/L NaCl solution to prepare the sulfidation corrosion layer, the temperature was 150 ℃, the H2S partial pressure was 0.9 MPa and the CO2 partial pressure was 0.6 MPa. XPS, SEM and XRD were applied to investigate the composition and structure of the corrosion layer. Results When FV（520）B stainless steel was corroded under the above conditions, the corrosion rate gradually decreased, the surface roughness of the sample first increased and then decreased. The components of corrosion products were mainly FeCO3, Fe3O4, FeS, FeS2, S, Fe3O4, Cr2S3, Cr2O3 and Cr（OH）3. Conclusion In the early stage of corrosion, the formation rate of FeS was higher than those of FeS2 and S, and the corrosion products were growing up, in the late period of corrosion, because the complete protection film of Cr2O3 and Cr（OH）3 was formed, the corrosion was inhibited and the main reaction was the formation of FeS2 and S. The particle size of the corrosion products on the surface of the sample and the roughness were both reduced.