油气管道的CO2腐蚀及防护研究进展

腐蚀控制是石油天然气管输过程中的一个重要问题.CO2是石油天然气管道中最常见的腐蚀介质,研究CO2腐蚀机制和防护措施具有重要科学意义和经济价值.综述了CO2的腐蚀机理,包括化学反应、电化学反应和传质过程.对现有的腐蚀理论进行了深入讨论,发现阴极反应对CO2腐蚀具有重要影响,CO2对阳极过程的影响尚未明确.在腐蚀机理的基础上,考虑管道实际工况,结合电化学实验结果阐述了各影响因素对CO2腐蚀行为的影响,并结合CO2腐蚀的影响因素讨论了常用管道防护措施的缺陷:阴极保护系统受电位影响较大,应确立新的阴极保护电位,以保证在杂散电流作用下的阴极保护效果;防护涂层容易在杂散电流干扰下发生降解,失去保护性;多数缓蚀剂对环境有害.最后,展望了未来CO2腐蚀和防护的发展方向:为进一步了解CO2腐蚀机理,需要对CO2的电化学腐蚀行为进行系统地实验测试.研究不同缓蚀剂的协同效应,使用环境友好型绿色缓蚀剂,利用新材料开发智能涂层和新型阴极保护系统,也是未来的研究方向之一.

Research Progress on CO2 Corrosion and Protection of Oil and Gas Pipelines

Corrosion control is an important issue in the process of oil and gas pipeline transportation. CO2 is the most common corrosion medium in oil and gas pipelines. It is of great scientific significance and economic value to study the corrosion mechanism and protective measures of CO2. The corrosion mechanism of CO2 is reviewed, including chemical reaction, electrochemical reaction and mass transfer process. The existing corrosion theories are discussed in depth, and it is found that the cathodic reaction has an important effect on CO2 corrosion, while the effect of CO2 on the anodic process is not clear. On the basis of the corrosion mechanism, in view of the actual working conditions of the pipeline, combined with the electrochemical experimental results, the influence of various factors on the corrosion behavior of CO2 is expounded. Combined with the influencing factors of CO2 corrosion, the defects of common pipeline protection measures are discussed:the cathodic protection system is greatly affected by potential, so a new cathodic protection potential should be established to ensure the cathodic protection effect under the action of stray current. Coating protection is easy to degrade and lose protection under the interference of stray current. Most corrosion inhibitors are harmful to environment. Finally, the development direction of CO2 corrosion and protection in the future is prospected:in order to further understand the corrosion mechanism of CO2, systematic experimental tests on the electrochemical corrosion behavior of CO2 are needed. It is also one of the future research directions to study the synergistic effect of different corrosion inhibitors, the use of environment-friendly green corrosion inhibitors, the use of new materials to develop intelligent coatings and new cathodic protection systems.