Dynamic simulation of a carbon dioxide transfer pipeline for analysis of normal operation and failure modes

Dynamical simulations have been performed for CO2 transfer through a fictive but realistic transport pipeline in order to evaluate the risk of phase transition during flow transients and pipe cooling. The simulation results provide a better understanding of transport phenomena during transport of CO2 from the capture point to the storage point of a carbon capture and storage (CCS) process. Two models were developed; one to describe pressure and flow dynamics within the transport pipeline and the other to simulate transient cooling and the generation and propagation of pressure waves in the pipeline. Together these models were used to determine pressure and flow fluctuations during transient pipe cooling as well as during operation modes of load change, start-up, shut-down, and compressor trip. Pipe cooling was found to result in the slow formation of two-phase flow. Quick shut-down and load change led to the occurrence of two phase flow which was restricted to the vertical section of pipeline (injection pipe) by controlling the flow through the final control valve. Quick shut-down created pressure oscillations in the pipe with a maximum amplitude of 3 bar. During start-up mode it took 12 days to completely fill the pipeline, 6 days of which involved flow in the two-phase region. Compressor trip showed no sign of crossing the phase boundary.