Experimental study of the full-scale burst failure behavior of carbon dioxide steel pipeline

Abstract

Carbon Capture, Utilization and Storage (CCUS) is an important strategic reserve technology to reduce CO2 emissions. Accelerating the application and development of CCUS technology is a realistic need and an important path for the energy industry to achieve the goal of carbon peak and carbon neutrality. It is the most economical method to transport CO2 from carbon source to carbon sink in supercritical state through pipeline. The key issue of supercritical/dense phase CO2 pipeline design is whether the pipeline steel has an adequate toughness to arrest running ductile fracture. For the study of toughness requirements of pipeline, full-scale burst test is the most direct and effective method at present. In order to research the toughness requirements of the supercritical CO2 pipeline, the first full-scale burst test of CO2 pipeline in China was carried out. The X65 steel pipeline with an outer diameter of 323.9 mm and a wall thickness of 7.2–7.6 mm was used as the test pipe. The test gas was 95% CO2 + 4% N2 + 1% H2, the test pressure was 11.85 MPa, and the temperature was 12.6 °C. The test results show that the axial prefabricated crack of the crack initiation pipe was successfully detonated and the crack propagated along the axial direction. On the west side, the crack was arrested at the girth weld of the two pipelines, and on the east side the crack was arrested ductilely because the base metal of the pipeline had sufficient toughness. The test steel pipe showed typical ductile shear fracture characteristics. The data of crack propagation velocity, pressure and temperature were collected, and the test results were accurate. After the burst of the pipe, the high-pressure gas in the pipe was sprayed upward and out in the opposite direction of the wind direction, and then diffused along the wind direction to the external field under the action of the wind velocity. This test provides data support for China to master the development, pipeline design and construction technology of million-ton CO2 pipeline. The test results will significantly improve the prediction accuracy of crack arrest toughness of CO2 pipeline of China, and provide important technical support for the safe construction and operation of global CO2 pipeline.

Keywords

• CO2 pipeline
• Full-scale burst test
• Crack propagation
• Leakage diffusion