Full-scale burst test of CO₂ pipeline

Objective Carbon Capture, Utilization and Storage (CCUS) is a pivotal technology for reducing atmospheric carbon dioxide levels. The pipeline transportation of supercritical/dense-phase CO₂ stands as the most cost-effective and practical means of conveying CO₂ from capture sites to storage locations. In supercritical/dense-phase CO₂ pipeline design, the key requirement is to mitigate long-range ductile fracture following the occurrence of cracks. At present, the most direct means for verifying the pipeline's fracture resistance during a burst event is full-scale burst tests.

Methods An investigative study revealed that a total of 11 full-scale burst tests have been carried out abroad. However, considering the disparities in pipe manufacturing processes and the different situations of actual CO₂ transportation, in order to explore the crack arrest toughness of China's supercritical CO₂ pipelines, the first full-scale burst test of carbon dioxide pipelines in China was successfully carried out. The test employed welded pipes made of Grade X65 steel, featuring an outer diameter of 323.9 mm and a wall thickness ranging from 7.2 mm to 7.6 mm. The test gas was composed of 95%CO₂, 4%N₂ and 1%H₂. The test pressure reached 11.85 MPa, and the temperature was maintained at 12.6 ℃.

Results The test results indicated a successful execution of the full-scale burst test on the CO₂ pipeline. The crack propagated along the pipeline from the crack initiating pipe. On the west side of the burst initiation location, the crack was arrested by ring-cutting at the circumferential weld of the two pipes. On the east side of the burst initiation location, the crack was arrested due to the toughness of the pipe base material, manifesting the typical characteristic of ductile shear fracture. Furthermore, crucial data regarding crack propagation speed, pressure and temperature were collected during the testing process.

Conclusion This test yields crucial data for China to acquire expertise in the development, design and construction technology of million-ton carbon dioxide transportation pipelines, marking China's important breakthrough in the field of CCUS technology research.