湿相CO2环境管道内沉积物及对腐蚀影响的定量化研究

 为研究湿相含CO₂腐蚀环境下管道底部沉积物对腐蚀的影响,在管道内底部湿相盐水成分分析的基础上,分析沉积物结垢趋势,研究管道内沉积物形成及类型。应用电化学噪声技术和金相分析法对湿相CO₂环境下20^#低碳钢无、有沉积物覆盖下的电位噪声、电流噪声及噪声电阻等腐蚀相关参数进行测试,对腐蚀形貌进行观察。结果表明,湿相CO₂环境下有沉积物相比无沉积物覆盖的20^#碳钢电流、电位噪声随时间变化曲线波动性大,噪声电阻的倒数降低87.5%~95%。通过室内及现场实验测试20^#低碳钢监测挂片定期清除沉积物、缓蚀剂防护条件下腐蚀失重及点腐蚀参数,得出定期清除沉积物及缓蚀剂防护能分别降低20^#碳钢均匀腐蚀80%、43%,点腐蚀速率57%、92%。

Sediment in the Formation in Wet CO2 Environment of Pipeline and Quantitative Study of Its Corrosion Effect

This paper studies the influence of the wetting phase in CO₂ corrosion environment with bottom sediments on the corrosion of pipeline. In the pipeline bottom, the wet analysis is conducted on the composition of brine, the sediment of scaling tendency, the sediment formation and the types of pipeline internal sediment. The electrochemical noise technique and the metallographic analysis are applied for the 20^# low carbon steel in the wet CO₂ environment, with no sediment covered under the potential noise, the current noise and the corrosion resistance noise, and the corrosion morphology is observed. The results show that, compared with the 20^# carbon steel without sediments, the potential noise and current noise have a time-varying volatility in the wet CO₂ environment, and the resistance noise is reduced by 87.5% ~95%. With the sediment removal and a regular monitoring of the corrosion inhibitor corrosion weight loss and corrosion and other parameters in laboratory and field experiments, the regular cleaning deposit and corrosion inhibitor levels of the 20^# low carbon steel sheet, can, respectively, be reduced by 80%, 43%, and 57%, 92% for the point corrosion rate.