海岸土壤环境对油气管道局部腐蚀的影响

Effect of Coastal Soil Environment on Localized Corrosion for Oil and Gas Pipelines

综述分析了海岸土壤环境对油气管道局部腐蚀的影响。首先,凝练了海岸土壤显著区别于陆地土壤和海底土壤的腐蚀环境特征,即具有高盐含量、高湿、与空气直接接触、气/液/固三相不均匀的组成结构和干湿交替变化等特点。其次,探讨了海岸土壤腐蚀环境因素对油气管道局部腐蚀发生和发展过程的影响。最后,分析了油气管道局部腐蚀研究思路和存在的难点,并对海岸土壤环境中管线钢的微区电化学研究方案进行了展望。

The direct cause for the explosion accident occurred by Dong Huang pipeline is that the corrosion of pipeline was enhanced by coastal soil, which in turn resulted in thinning and then cracking of the pipe. Because localized corrosion cracking in coastal soils is a serious threat to the integrity and security for the pipeline, the effect of the coastal soil environment on localized corrosion for oil and gas pipelines was analyzed systematically. Typical corrosion environmental characteristics were acquired and then analyzed firstly for the specified coastal soil, which in general is rather different from the terrestrial soil and seabed soil distinctly. The coastal soil is characterized as a mixture of gas/liquid/solid multi- phases with high salt- and water- content and good air aeration, while it experiences dry-wet cycles periodically. The effect of the coastal soil environment on the initiation and propagation of localized corrosion for oil and gas pipelines is discussed. Finally,the trends and difficulties of the study in oil and gas pipeline localized corrosion are analyzed, and in the end, a scheme of microe electrochemical study is peculiarly prospected.