Impact of Associated Gases on Equilibrium and Transport Properties of a \mathrm{CO}_{2} Stream: Molecular Simulation and Experimental Studies

During the various carbon dioxide capture and storage (CCS) stages, an accurate knowledge of thermodynamic properties of \(\mathrm{CO}_{2}\) streams is required for the correct sizing of plant units. The injected \(\mathrm{CO}_{2}\) streams are not pure and often contain small amounts of associated gaseous components such as \(\mathrm{O}_{2}, \mathrm{N}_{2}\) , \(\mathrm{SO}_{x}, \mathrm{NO}_{x}\) , noble gases, etc. In this work, the thermodynamic behavior and transport properties of some \(\mathrm{CO}_{2}\) -rich mixtures have been investigated using both experimental approaches and molecular simulation techniques such as Monte Carlo and molecular dynamics simulations. Using force fields available in the literature, we have validated the capability of molecular simulation techniques in predicting properties for pure compounds, binary mixtures, as well as multicomponent mixtures. These validations were performed on the basis of experimental data taken from the literature and the acquisition of new experimental data. As experimental data and simulation results were in good agreement, we proposed the use of simulation techniques to generate new pseudo-experimental data and to study the impact of associated gases on the properties of \(\mathrm{CO}_{2}\) streams. For instance, for a mixture containing 92.0 mol% of \(\mathrm{CO}_{2}\) , 4.0 mol% of \(\mathrm{O}_{2}\) , 3.7 mol% of Ar, and 0.3 mol% of \(\mathrm{N}_{2}\) , we have shown that the presence of associated gases leads to a decrease of 14 % and 21 % of the dense phase density and viscosity, respectively, as compared to pure \(\mathrm{CO}_{2}\) properties.