To deliever mixed natural gas and hydrogen with the existed natural gas pipelines is an important way to achieve efficient hydrogen transportation.However,corrosion defects present on these aged pipelines will affect the diffusion and enrichment of hydrogen atoms,potentially causing hydrogen embrittlement in the pipeline steel and further leading to the pipeline failure.In addition,corrosion defects on pipelines often exist in the form of adjacent double corrosion defects and even multiple corrosion de-fect groups.The interaction between adjacent defects can complicate the hydrogen diffusion and enrich-ment behavior,and ultimately affect the hydrogen induced failure behavior of the pipeline.In order to study the distribution of hydrogen concentration on pipelines containing double corrosion defects,a finite element model coupled with stress field and diffusion field was developed.The influence mechanism of corrosion defect length,defect spacing and applied tensile strain on hydrogen diffusion and enrichment behavior in steel was investigated in terms of the stress coupling behavior between the two corrosion de-fects.The results showed that the existence of corrosion defects caused the accumulation of hydrogen at-oms in steel,and the value and location of the maximum hydrogen concentration in accumulation area changed with tensile strain,defect length and defect spacing.However,when the distance between the two defects is large enough,they will not have a superposition effect on the hydrogen diffusion and en-richment,and thus they can be regarded as two independent defects.This study provides a theoretical reference for the safety assessment of hydrogen damage in hydrogen transmission pipelines with double corrosion defects.
关键词
双腐蚀缺陷/氢分布/有限元模拟/X52管线钢
Key words
double corrosion defects/hydrogen distribution/finite element modeling/X52 pipeline steel
维普
万方数据