Full-Scale Burst Test of Hydrogen Gas X65 Pipeline

Full-scale burst test of X65 UOE linepipe, with 559mm outer diameter and 13.5mm wall thickness, pressurized at 16MPa by hydrogen gas was conducted. A 735mm long crack was introduced by explosive shaped charge over circumferential weld. The cracks were initiated and propagated in the both directions. The propagated crack lengths were 600mm and 270mm. J integral resistance curves were obtained from drop-weight as well as quasi static tests for the tested pipe material which was subjected to hydrogen charging. The tested steel showed little change in the resistance curves under realistic charging condition. Numerical simulation model of dynamic crack propagation, coupled with gas decompression behavior considering gas escape from opened crack, showed that an initiated crack was arrested at shorter distance in hydrogen gas pipelines than in methane gas pipelines, primarily due to earlier gas decompression in the former. The present results, together with the earlier full-scale burst tests conducted by the authors, demonstrated that hydrogen gas pipelines can be operated safely by using modern high-strength and high-toughness steel linepipes.