Abstract
The implementation of the CCS (CO2 Capture and Storage) technology is one of the solutions to capture carbon dioxide emitted from industrial and energy generation sources for mitigation of green-house effects. Carbon dioxide is classified as asphyxiant in high concentrations with occupational exposure limits of 30000 ppm. Its relief in large quantities combined with its density, higher than air, could fill populated regions with unexpected dangerous effects. This study focuses on transportation of carbon-dioxide in pipelines, at high pressure as dense phase, and its release in case of emergency conditions. For the evaluation of dispersion effects of carbon dioxide in the ambient, it is of fundamental importance being able to calculate the flowrate of the fluid dispersed in the ambient, the pressure and temperature changes in the pipeline, the time required to obtain the complete discharge of the fluid, as function of a large number of operating and ambient conditions such as the pipeline profile, thermal insulation, ambient temperature etc. This study provides an example of how this analysis can be performed, the thermodynamic models required, the solution algorithm to be applied in the two main disciplines involved i.e., process engineering and flow-assurance. During normal operations CO2 is transported as supercritical fluid i.e., at pressure above the thermodynamic critical point pressure. The dynamic simulation applied in this study is rigorous from the thermodynamic and fluid dynamic point of view. In case of fast depressurization, the change of the fluid temperature caused by the liquid phase evaporation may result in damages to the pipeline since very low temperatures may induce metal brittle effects. The calculations are performed using a dynamic software code which has provided high quality results when compared to experimental data and results obtained by other commercial simulators.
