局部腐蚀条件下内压对管道腐蚀速率的影响

EFFECT OF INTERNAL PRESSURE AND LOCALIZED CORROSION ON PIPELINE CORROSION RATE

管道在生产过程中发生腐蚀,从而导致服役管道的损坏。除化学腐蚀外,管体中由于流体压力而产生的应力也将影响管道的腐蚀,局部腐蚀形成的应力集中将极大的减小管道的耐久性寿命。文章针对生产管道所受内压力和局部应力集中会加速腐蚀速率,严重缩短管柱服役寿命这一现象,结合化学力学效应理论,分二向应力和三向应力两种情况,建立了内压力影响管道腐蚀速率的解析模型。算例计算结果显示,该模型所得结果与目前文献中应力对腐蚀速率的影响实验研究结果相符;得出了管道所受应力越大,管道实际寿命衰减得越快等结论,对确定管道的寿命具有参考意义。

Pipeline will be damaged by corrosion in the process of oil and gas transferring.The stress caused by high pressure fluid and stress concentration caused by localized corrosion will affect the rate of pipeline corrosion.This paper focused on the phenomenon that the internal stress which loaded on the corrosive pipeline and localized stress will accelerate corrosion rate and shorten the pipeline service life significantly,combined the theory of mechanochemical effect,the analytical model for pipeline corrosion accelerating rate by stress with two dimensions stress and three dimensions stress was established.According to sample result,the result from this model is consistent with literature result which achieved by experimental research.This model and calculating result can provide reference for exact determination pipeline operating life.