Investigation on crack propagation and reasonable wall thickness of supercritical CO2 pipeline

Carbon Capture, Utilization and Storage (CCUS) is one of the key technologies to reduce emissions of greenhouse gases in fighting against global climate change. Supercritical CO2 pipeline transportation is the safest and most economical way to transport CO2 over long distances. However, due to the complex and changeable service conditions and phase changes of the pipeline, the pipeline is prone to long-range propagation after crack initiation, affecting the safe operation of the pipeline. The instrumented impact experiment of X52 pipeline material is carried out to study the crack propagation mechanism of supercritical CO2 pipelines. The inversion model is conducted using the MATLAB-PYTHON-ABAQUS platform, and the optimal Cohesive Zone Model parameters of the X52 pipeline are obtained. To simulate the crack propagation behavior of pipeline, a three-dimensional model of the CO2 pipeline is established, and the influence of key parameters such as internal pressure, wall thickness, and pipe diameter on the crack propagation velocity of pipeline is analyzed. The results show that the Cohesive trapezoidal constitutive model can efficiently describe the fracture process of a supercritical CO2 pipeline, and the experimental inversion error is less than 10%. Reducing internal pressure and pipe diameter while increasing wall thickness can reduce the risk of pipeline crack propagation accidents. In addition, the reasonable wall thickness of China's supercritical CO2 pipeline demonstration project is obtained under different design pipe diameters. The research results can provide reference for the reasonable design and safe operation of CO2 pipeline.