Fatigue lifetime prediction of rubber O-rings in CCUS systems: A coupled diffusion-deformation-fatigue model

Carbon capture, utilization, and storage (CCUS) technology serves as a critical approach for industrial emissions reduction. However, during high-pressure CO₂ pipeline transportation, the sealing performance of rubber O-rings at the pipeline end quick-opening blind flange is crucial to system integrity. Seal failure may not only lead to substantial CO₂ leakage, significantly compromising the CCUS system's emission reduction efficiency, but also pose serious safety hazards due to sudden high-pressure gas release. Current research on the diffusion behavior of CO₂ in rubber materials and the impact of its induced deformation on the fatigue life of sealing components remains notably insufficient. To address this issue, this study develops a finite element analysis (FEA) model coupling diffusion-deformation-fatigue life based on gas diffusion and hyperelasticity theories to assess the fatigue life of rubber O-ring. The results show that a moderate compression proportion (approximately 15 %) is beneficial for prolonging the O-ring fatigue life while minimizing leakage risks. Increasing cavity diameter reduces the fatigue life of the O-ring. As CO₂ pressure increases from 1 MPa to 5 MPa, the fatigue life of O-rings with cavities decreases from infinity to 7.36 cycles. Moreover, the acceleration of the depressurization rate adversely affects the fatigue life of O-rings containing cavities. The results provide essential guidelines for optimizing the design of CCUS pipeline sealing systems, ensuring long-term operational reliability of high-pressure CO₂ transportation infrastructure while mitigating potential safety hazards induced by seal failure.