含腐蚀缺陷长输管道剩余强度影响参数定量评价

针对管道运行过程中腐蚀缺陷导致管道事故频繁发生等问题,主要采取了NG-18、ASME B31G-1991、API 579和DNV RP-F101等方法对管道剩余强度的评价。四种评价方法对指标参数失效压力、流变压力、缺陷长度、Folias鼓胀因子以及腐蚀缺陷面积计算各有不同,分别做了各参数与评价结果定量影响研究。实验研究表明:管线钢材级别越高,不同定义下计算的流变压力相差减小,对管道剩余强度评价的影响较小;随着缺陷长度的增加,鼓胀因子相对差逐渐变大,对管道剩余强度评价的影响较为敏感。对于短缺陷管道,NG-18评价方法较为合适;基于实际爆破数据,相对于ASME B31G-1991评价方法,DNV RP-F101评价结果误差较小;对腐蚀缺陷管道缺陷面积的计算,ASME B31G-1991方法精度较高,是一种普遍适用的评价方法。

Quantitative Evaluation of Residual Strength of the Long-distance Pipeline With Corrosion Defects

In view of the problem that pipeline accidents occurred frequently during the operation because of pipeline corrosion defects, NG 18, ASME B31G-1991, API579 and DNV RP-F101 methods were used to evaluate residual strength of the pipe. The four evaluation methods have different computation processes for index parameters including failure pressure, rheological parameters, defect length, Folias ballooning factors and corrosion defect area. Impact of the parameters on the evaluation results was quantitatively studied. The results show that,the higher the level of pipeline steel, the lower the calculated rheological stress difference under different definition, the less the effect on the pipeline residual strength evaluation; With the increase of the length of the defect, ballooning factor relative difference increases gradually, the impact on the pipeline residual strength evaluation is more sensitive. For short defect pipe, NG-18 evaluation method is relatively appropriate; Based on the actual blasting data, compared to the ASME B31G-1991 evaluation method, the error of DNV RP-F101 evaluation result is smaller; In defect area calculation of pipeline with corrosion defects, and ASME B31G-1991 method has high precision, is a kind of widely used evaluation method.