Fracture process characteristic study during fracture propagation of a CO2 transport network distribution pipeline

The transportation of carbon dioxide (CO2) from the capture point to the pooling site through distribution tubes is a crucial link in the carbon capture, utilization, and storage (CCUS) chain. Existing experiments have not been conducted to study the full-scale fracture of the CO2-distributed pipelines, the pressure and temperature evolution inside the pipe during crack initiation, fracture extension, and stopping have not been revealed. The rate of fracture extension velocities has not been quantitatively described, and the crack morphology has not been analyzed. This paper conducted the first supercritical CO2 pipeline full-scale fracture experiment based on a novel experimental setup with a total length of 21.7 m and the inner diameter of 98.3 mm, 16.7 m of which is the main pipeline and 5 m is the sacrificial pipeline. After the sacrificial pipeline rupture, high-frequency transducers were used to measure the change in fluid pressure, and multilayer thermocouples monitored the temperature distribution in four cross-sections within the pipe. Moreover, the decompression wave propagation velocity of supercritical CO2 and sacrificial pipeline fracture velocity has been obtained and calculated, respectively. The microscopic morphology of the cracks obtained by scanning electron microscopy revealed the failure mechanism of the sacrificial pipeline with prefabricated defects. This work establishes a reliable experience for industry-scale CO2 pipelines and creates a pipeline design foundation for higher security transport in the future.