'Co2cktails in a Pipeline’: The Phase Behaviour of Co2 With >20 Impurities

Abstract

CO2 in transportation pipelines will contain several impurities due to the wide range of potential emitters. Depending on the physical and chemical nature of the impurities, these will induce diverse phase equilibria. This will be the case even if the impurities are at the ppm level. Certain impurities can induce undesirable liquid phases when the system operates in low pressure single gas phase mode. These liquid phases can appear at normal operating temperatures and can lead to corrosion mechanisms. Thus, there is a need to accurately predict the thermodynamic behaviour of the multicomponent mixture that will be transported in a CCS network. In this work, we investigate the phase behaviour of a CO2 multicomponent mixture. While the aim is to qualitatively identify the potential number of phases that could form, we focus on the potential issue of liquid dropout at low pressure conditions during gas phase operation.