Clathrate hydrate formation of CO2 in the presence of water miscible (1,4-dioxane) and partially water miscible (cyclopentane) organic compounds: Experimental measurement and thermodynamic modeling

In this paper, the hydrate formation pressure values for the systems of water + CO2, water + cyclopentane + CO2, water + 1,4-dioxane + CO2, and water + 1,4-dioxane + cyclopentane + CO2 were obtained at different mass fractions of 1,4-dioxane (5.1, 10.17, and 25.31) by using the isochoric pressure search method. The results showed that in the system of water + cyclopentane, cyclopentane is a good promoter in comparison with pure water (Delta T = 10.9 K in P = 2.257 MPa), so it can be used for CO2 capturing and storage. Also the 1,4-dioxane at the system of water + 1,4-dioxane + CO2 could not change the equilibrium pressure, so it can not be used as an inhibitor or promoter even at high concentrations. The behavior of four-components system with Delta T = 11.6 K in P = 2.158 MPa, water + 1,4-dioxane + cyclopentane + CO2 is similar to the water + cyclopentane + CO2 system, so the 1,4-dioxane does not have a significant effect. In addition, the data were predicted by using thermodynamic modeling (gamma-phi approach, Vanderwaals Platteeuw Theory for hydrate phase, Non-random two liquid (NRTL) for liquid phase and Peng-Robinson for vapor phase). The percent of average relative deviation of pressure shows that the predicted results are in good agreement with the experimental data.