Abstract
This paper describes the testing, comparison and application of global sensitivity techniques for the study of the impact of the stream impurities on CO2 pipeline failure. Global sensitivity analysis through non-intrusive generalised polynomial chaos expansion with sparse grids is compared to more common techniques and is found to achieve superior convergence rate to crude Monte Carlo, quasi-Monte Carlo and EFAST for functions with up to a moderate level of “roughness”. This methodology is then applied to the hypothetical full bore rupture of a 1km CO2 pipeline at 150bara and 283.15K. The sensitivity of the ensuing outflow to the composition of a quaternary mixture of CO2 with N2, CH4 and O2 as representative stream impurities. The results indicate that the outflow rate is highly sensitive to the composition during the early stages of depressurisation, where the effect of the impurities on phase equilibria has a significant impact on the outflow.
► gPCE-based sensitivity analysis with sparse grids is introduced for complex systems. ► A comparison between this gPCE-based technique and conventional ones is presented. ► gPCE-based methodology is used to explore the impact of impurities in CCS streams.