输气管道内腐蚀缺陷剩余强度评估方法适应性分析与应用

The Adaptability Analysis and Application of the Residual Strength Evaluation Method of Corrosion Defects Within Gas Pipeline

针对输气管道易受腐蚀导致失效影响生产等问题,设计了一套内腐蚀缺陷管道剩余强度评估方法。首先主要介绍了4种剩余强度评估方法,并结合实例解析对这4种方法进行了适应性分析,对比分析表明:DNV RP-F101方法最为可靠,并依托DNV RP-F101标准编制了计算内腐蚀缺陷剩余强度的程序,最后通过工程实例进行验证。结果表明,当管道腐蚀长度为腐蚀缺陷深度10倍时,管道腐蚀缺陷程度达到40%为许用压力值变化拐点,缺陷程度增大,许用压力加快减小,应将管道腐蚀程度控制在40%以内,甚至更低;当管道腐蚀长度为腐蚀缺陷深度100倍时,管道腐蚀缺陷程度达到10%为许用压力值变化拐点,缺陷程度越大,许用压力加快减小;应将管道腐蚀程度控制在10%以内,甚至更低;基于DNV RP-F101方法这套剩余强度评估程序,具有快速、高效、实用等特点,可为输气管道剩余强度评估提供技术支持。

In view of the problem that the gas pipeline is easily affected by corrosion and the failure happens, it is designed a set of pipeline corrosion defects in residual strength evaluation methods. First four kinds of residual strength evaluation methods are mainly introduced, and combined with examples, the adaptability analyses of these four kinds of methods are conducted. The comparative analysis show that DNV lip - F101 method is the most reliable, the procedure calculating the corrosion defect of residual strength is compiled based on this method and finally it is validated by an engineering example. Results show that, when the length of the pipeline corrosion is 10 times for the depth of the corrosion defects, the degree of pipeline corrosion defects 40% is the allowable pressure values change turning point, the greater the defect level, the lesser the allowable pressure speed, and so pipeline corrosion degree should be controlled within 40%, even lower; when the length of the pipeline corrosion is 100 times the corrosion defect depth, degree of pipeline corrosion defects of 10% is the allowable stress values change turning point, the greater the defect level, the lesser the allowable pressure speed and pipeline corrosion degree should be controlled within 10%, even lower; the residual strength assessment process based on DNV RP- F101 method has characteristics of rapid, efficient, practical and can provide technical support for gas transmission pipeline residual strength evaluation.