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针对常用含腐蚀缺陷管道可靠性评价方法较多且适用性和保守程度不一的问题,对一种新的腐蚀管道失效压力预测公式进行误差分析,证实该模型比常用ASME B31G-2009、DNV RP-F101、PCORRC、CSA Z662-07、RAM PIPE REQUAL、NETTO ET AL等方法具有更高的预测精度。基于该预测公式,建立腐蚀缺陷管道失效极限状态方程,采用蒙特卡洛模拟方法计算了管道失效概率,并与其它常用工业标准与方法的计算结果进行对比分析。结果表明:基于该模型计算的失效概率与PCORRC,ASME B31G-2009以及DNV RP-F101许用应力法计算结果相近,进行可靠性分析具有较好的适用性。通过参数敏感度分析得出结论:管道壁厚、直径、内压、径向腐蚀速率等随机变量的变异系数的增大对管道失效概率的影响具有双向性,可能造成管道失效概率的增加,也可能导致管道失效概率的减小。指出径向腐蚀速率和管道内压是影响腐蚀管道可靠性的两个关键因素。
Aiming at the problems of commonly used reliability assessment methods for corrosion-degraded pipelines and their applicability and conservativeness, the error analysis of a new formula for prediction of failure pressure of corroded pipelines is conducted. The results show that the model is better than the conventional ASME B31G-2009, DNV RP -F101, PCORRC, CSA Z662-07, RAM PIPE REQUAL, NETTO ET AL and other methods have higher prediction accuracy. Based on this prediction formula, the equation of state of failure limit of pipeline with corrosion defects was established. The probability of pipeline failure was calculated by Monte-Carlo simulation and compared with the results of other commonly used industry standards and methods. The results show that the failure probability calculated based on this model is similar to the allowable stress method of PCORRC, ASME B31G-2009 and DNV RP-F101, and the reliability analysis has good applicability. Through the analysis of parameter sensitivity, it is concluded that the increase of coefficient of variation of random variables such as pipe wall thickness, diameter, internal pressure and radial corrosion rate have a bidirectional effect on pipeline failure probability, which may increase the probability of pipeline failure and This may lead to a decrease in the probability of pipeline failure. It is pointed out that radial corrosion rate and internal pressure of pipeline are the two key factors affecting the reliability of corrosion pipeline.