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 CO 2 separation from flue gases, and in subsea flue gas CO 2 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CO 2 , and COC 3 H 8 (propane) clathrate hydrates. Data were generated by a reliable step‐heating technique validated using measured data for CO 2 and CH 4 hydrates. Data for CO and COC 3 H 8 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.