氢致微裂纹应力腐蚀损伤管道的寿命预测

Service life prediction of pipeline under hydrogen-induced microcrack stress corrosion

  • 摘要: 管道的断裂损坏常常始于微裂纹,研究微裂纹的形成原因、分布情况、扩展规律、扩展速率和影响因素等对于管道的寿命预测有重要的参考价值。基于损伤力学原理分析了管道应力腐蚀损伤演化模型,根据微裂纹扩张的位能和动能计算式以及能量守恒原理,推导得出氢致微裂纹扩展速率与管道剩余寿命的关系:微裂纹扩展速率与氢压有关,随着氢压的增大而增大。结合实例计算了管输介质H2S和CO2含量对管道剩余寿命的影响规律,结果表明:当管道中同时存在CO2和H2S时,管道腐蚀加剧;当输送压力和其他参数不变时,随着H2S和CO2含量增加,管道剩余寿命逐渐减小。

     

    Abstract: Fracture of pipeline usually begins with microcracks, and it is very important to study its formation, distribution, propagation in the service life prediction of pipeline. The evolution model of stress corrosion damage of pipe is analyzed based on the damage mechanics theory. The relationship between the residual life of pipeline and the growth rate of hydrogen microcrack is derived according to energy conservation law and the calculation formula for the expansion of potential energy and kinetic energy. Result shows that crack growth rate is increased with the increase of hydrogen pressure. The effect of H2S and CO2 contents(two main corrosion factors) on the residual life of pipeline is analyzed through a case. The results are as follows: (1) the corrosion of pipeline is aggravated when both H2S and CO2 exist in the pipeline; (2) the residual life of pipeline will decrease if H2S and CO2 contents are increased and the operation pressure and other parameters are constant.

     

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