Impact of variability in inlet operating conditions on CO2 transport in pipelines

The success of CCS technologies relies on the effectiveness and safety of the infrastructure for the transport of carbon dioxide in pressurized pipelines. Unlike natural gas networks, long-distance carbon dioxide transport presents critical design challenges, such as the need for repressurization to prevent two-phase flow conditions and potential freezing. To address this, we propose a comprehensive assessment framework that combines high-fidelity numerical simulations with a stochastic approach based on the Polynomial Chaos Expansion (PCE). Specifically, we employ the Homogeneous Equilibrium Model (HEM) to compute key quantities of interest (QoIs) — related to pressure drop and the maximum distance before repressurization is required — under a design scenario inspired by the Cortez pipeline (Colorado, USA). Based on PCE surrogates, we then perform global sensitivity analyses and uncertainty quantification to evaluate how variability in inlet parameters influences these QoIs, mapping results across a range of realistic operating conditions. Our results provide critical insight into the risks connected with CO2 transport and support the optimal design of operating conditions. Moreover, the proposed methodology is general and easily applicable to other CO2 transport facilities.