An approach of quantitative risk assessment for release of supercritical CO2 pipelines

Transportation of Carbon Dioxide (CO2) is an essential part of Carbon Capture and Storage (CCS) chain. Transportation using pipelines is known as one of the most economical ways for large-quantity of CO2. In CCS projects, it is very important to ensure the safe operation of the CO2 pipelines. Thus in the design stage, the risk associated with CO2 pipelines should be identified. This paper reports a method of Quantitative Risk Assessment (QRA) for the possible release of supercritical CO2 (scCO2) pipelines, including the individual risk and social risk. In this method, the data of failure frequency was summarized and the failure frequency suitable for CO2 pipelines was modified based on the effect of third-party activities. Furthermore, the fatal length was introduced to describe the integrated fatality along the pipeline. A two-phase model for CO2 release and a modified Gaussian plume model for CO2 dispersion were used to obtain the release consequences in CO2 pipeline QRAs for the first time. The results show that the modified failure frequencies of a full-bore rupture and a puncture are both 2.32 × 10−4 km−1 year−1. To demonstrate the method, a QRA case based on a hypothetical accident release of a scCO2 pipeline was presented. The QRA model proposed provides a potential framework to determine the safe distance of CO2 pipelines.