Research progress of BTC method and feasibility of its application to calculate crack arrest toughness of CO₂ pipeline

Objective Carbon Capture, Utilization, and Storage (CCUS) technology has played a vital role in achieving the strategic goal of "carbon neutrality". However, pipeline transmission, a critical component in the CCUS industry chain, is currently encountering challenges, particularly related to ductile crack arrest in dense-phase CO₂ pipelines.

Methods Drawing upon the crack arrest control mechanism, the research progress of the Battelle Two-Curve (BTC) method was thoroughly investigated to establish a foundation. A subsequent analysis was conducted to expose its technical standing and limitations in the application for controlling crack arrest in natural gas pipelines. Following this, the BTC correction method for crack arrest toughness was examined across three key factors: Charpy impact absorbed energy, drop weight absorbed energy, and crack tip opening angle. Taking into account the properties of dense-phase CO₂, the feasibility of utilizing the BTC method to calculate the crack arrest toughness of CO₂ pipelines was explored.

Results Building on the BTC correction method for controlling crack arrest in natural gas pipelines, a new correction approach utilizing BTC was proposed for crack arrest control of CO₂ pipelines. This method was developed from two perspectives: driving force and resistance, while incorporating the velocity criterion from the design criteria for crack arrest in dynamic ductile propagation. Through the examination of data from prior full-scale burst tests on CO₂ pipelines, currently recognized as the most effective means for determining the crack arrest toughness of dense-phase CO₂ pipelines, a correction coefficient range for the BTC method was established. This range serves as a benchmark for ensuring the safe operation of CO₂ pipelines and promoting the broader adoption of CCUS technology.

Conclusion The research on utilizing the BTC correction method to calculate the crack arrest toughness of dense-phase CO₂ pipelines is still in its early stages of development. The correction coefficient for the BTC method derived from available full-scale burst test data of CO₂ pipelines is inadequate, primarily due to the scarcity of experimental data and their limited application scope. Consequently, further research necessitates an integration with numerical simulation to develop more effective correction methods.