Carbon monoxide clathrate hydrates: Equilibrium data and thermodynamic modeling

Carbon monoxide occurs in abundance throughout the cosmos, potentially in clathrate form, whereas on Earth, it forms a notable constituent of industrial flue gases. It has been proposed that hydrate technology could be used in CO₂ separation from flue gases, and in subsea flue gas CO₂ disposal. This - and the likely widespread occurrence of CO clathrates in the cosmos - means it is important that the phase behavior of CO hydrates is known. Here, we present experimental H-L-V (hydrate-liquid-vapor) equilibrium data for CO, CO-CO₂, and CO-C₃H₈ (propane) clathrate hydrates. Data were generated by a reliable step-heating technique validated using measured data for CO₂ and CH₄ hydrates. Data for CO and CO-C₃H₈ clathrates have been used in the optimization of Kihara potential parameters for CO, reported here, facilitating the extension of a thermodynamic model to the prediction of CO hydrate equilibria. Model predictions are validated against independent experimental data for CO-CO ₂ (structure I) systems, with good agreement being observed. © 2005 American Institute of Chemical Engineers'.