双点腐蚀缺陷对管道剩余寿命的影响

Influence of Double Corrosion Defects to Residual Life of Pipelines

腐蚀是造成油气管道失效和破坏的主要原因之一。在腐蚀严重区域,由于同时存在单点腐蚀和双点腐蚀,管道面临着更大的失效和破坏风险。若仍按单点腐蚀预测该区域管道的剩余寿命,进行可靠性分析,会造成较大的分析误差。文中应用Monte Carlo法,分别计算单点腐蚀和双点腐蚀的失效概率。通过比较分析发现:由于双点腐蚀的相互作用,管道的失效概率明显增加,剩余强度和剩余寿命减小;随着双点腐蚀蚀坑间距的不断增加,其失效概率不断降低,最终趋于单点腐蚀失效概率。

Corrosion is one of the main reasons which leads to the failure and damage of oil and gas pipelines. In the serious corrosion area, due to the single and double corrosion, the pipeline faces more risks. If predicting the residual life and making reliability analysis using single corrosion model, it will cause greater error. By using Monte Carlo method, the failure probability of single and double corrosion defects was calculated. Though comparing, it can be found that due to the influence of the double corrosion, the failure probability increases and the residual strength and life decrease and that with the pit spaces increasing, the failure probability decreases until it tends to the failure probability of the single corrosion.