Dynamic simulation of pipelines containing dense phase/supercritical CO2-rich mixtures for carbon capture and storage

Carbon dioxide mixtures from separation plants contain usually some impurities. Major impurities include nitrogen, argon, hydrogen and oxygen, depending on the capture technology used for the removal of CO2. The mixture composition determines the critical point data, and the values of critical pressure and critical temperature define, in turn, the limits of dense phase/supercritical pipeline operating conditions. The simulation of dynamic behaviour of three dense phase/supercritical CO2-rich mixtures was carried out in this study. The pipeline CO2 flow model was formulated with the assumption of one-dimensional, nonisothermal flow condition. An illustration of the performance of the model by an example of a fictive but realistic onshore CO2 pipeline is given. The results show that the type and quantity of impurities have a significant influence on the hydraulics of the pipeline transportation system under transient conditions. They also indicate that the transportation costs vary and are dependent on the capture technology used.

► Formulation of governing equations for unsteady CO2 pipeline flow.
► Modeling the fast transient in the CO2 pipeline.
► Evaluating the effect of impurities in CO2 mixture on pressure–temperature conditions.
► Comparison of compressor work input necessary to transport different dense phase CO2 mixtures.