腐蚀管线的剩余寿命预测

预测管线的腐蚀变化趋势及腐蚀对管线结构完整性的危害是评价管线剩余寿命的关键步骤。将影响管线剩余寿命的各种因素看成是分布各异的随机变量 ,建立了预测管线失效的概率数学模型。利用这一模型 ,研究了腐蚀速率、缺陷深度、管道壁厚和工作压力等因素对管线可靠性的影响。结果表明 ,各参数的不确定性越大 ,管线的可靠性越低 ;缺陷深度在腐蚀缺陷形成初期 ,对管线的可靠性有很大影响 ,而随着时间的推移 ,腐蚀速率将对管线的可靠性有较大影响。对一条输油管线 ,基于管线腐蚀检测数据 ,对 1km长度的管道进行失效概率统计分析得到的腐蚀速率能够对管线全线的安全状况做出合理预测 ,从而为管线的进一步维修与检测提供参考资料。

Prediction method for remaining life of corroded pipelines

Prediction of the corrosion in pipeline and the effects of corrosion on the structural integrity of the pipeline is a key step for the assessment of the remaining life of a pipeline. A probabilistic mathematical model was set up, taking various kinds of factors influencing the remaining life of a pipeline as random factors. The effects of corrosion rate, defect depth, thickness of pipe and operation pressure on pipeline reliability were investigated with this model. It is concluded that the larger the uncertainty of each parameter is, the lower the pipeline reliability will be. Defect depth has a significant influence on the pipeline reliability in the early corrosion period, while radial corrosion rate has the most significant contribution to pipe corrosion in the course of time. The corrosion rate per kilometer of pipeline obtained after statistic analysis on inspection data can be used to predict the failure probability along the whole pipeline. The obtained result is of reference to further maintenance and inspection of pipeline.