Effect of an Aqueous Phase on CO2/Tetradecane and CO2/Maljamar-Crude-Oil Systems

Summary The effect of the presence of an aqueous phase on the phase behavior of the CO2/tetradecane and the CO2/Maljamar-crude-oil systems has been experimentally determined. Both the salinity and the amount of the aqueous phase were varied to test several methods of modeling. In the first technique, the amount of CO2 "lost" to the aqueous phase was determined using Henry’s law, decreasing the overall ratio of CO2 to hydrocarbons, while the Peng-Robinson equation of state (PR EOS) was used to determine the phase distribution of the hydrocarbon phases. In the second technique, the equation of state (EOS) was modified to predict the densities and compositions of not only the hydrocarbon phases, but also the aqueous phase. Simply accounting for CO2 solubility by incorporating Henry’s law, used in conjunction with the Poynting correction and an empirical factor for salinity, not only gave results nearly identical with the EOS approach, but also required less computational effort. Both methods gave good agreement with the experimental data.