Thermodynamic method for the prediction of solid CO2 formation from multicomponent mixtures

The increase in GHG concentration has a direct effect on global climate conditions. Among the possible technologies to mitigate GHG emissions, CCS is being accepted to gain emission reduction. Such technology also involves cryogenic CO2 capture processes based on CO2 freeze-out or where the formation of solid CO2 must be avoided. Captured CO2 is usually transported in pipelines for the reinjection. The risk associated to the release of CO2 is due to the changing temperatures and pressures the system may experience, which can lead to the deposition of solid CO2 where it must be avoided. Prolonged exposure to dry ice can cause severe skin damage and its resublimation could pose a danger of hypercapnia. It is, thus, necessary to build up a tool able to predict the conditions in which CO2 can freeze-out. A thermodynamic methodology based on cubic EoSs has been developed which is able to predict solid–liquid–vapor equilibrium of CO2 mixtures with n-alkanes or H2S which are usually found in equipment for acidic gas, mainly natural gas, treatment. The focus is a detailed analysis of the method performances when more than two components are present since, for such a case, literature does not provide significant modeling results.