Leakage diffusion and safety assessment of CO₂ pipeline transportation flange based on CFD simulation

Carbon capture and storage technologies play crucial roles in mitigating atmospheric greenhouse gases (GHGs). Pipeline transportation is the primary method of CO 2 transportation, making pipeline safety a priority. In this study, Fluent software was used to create a model for annular edge leakage flanges, which significantly differs from the traditional pinhole leakage model. This study aims to examine the impact of CO 2 pipeline flow and pressure on the diffusion of gas leaking from the flange and to develop a precise correlation between the diffusion distance and substance concentration. The results indicate that an increase in flow and pressure intensifies the diffusion of the flange leakage. Specifically, for a leakage lasting 96 s at flow rates of 0.7 and 10 m 3 /h, the diffusion ranges for the 5% concentration alarm threshold are 0.47 and 2.86 m, respectively. Furthermore, at a speed of 10 m/s and a pressure of 0.4 MPa, the diffusion ranges for 5 and 2% alarms are similar, spanning from 0.33 to 0.35 m. This study provides theoretical support and technical improvements to ensure the safe operation of pipelines.