Accelerated formation of THF-H₂ clathrate hydrate in porous media

Porous media were used to control the hydrogen clathrate particle size in order to accelerate its formation kinetics. Stoichiometric tetrahydrofuran- hydrogen binary clathrate hydrates with ∼1 wt % hydrogen loading formed in the mesopores of four porous media with median pore diameters of 49,65,100, and 226 À at 270 K and hydrogen pressure of 65 bar. The minimum formation time for the tetrahydrofuran-hydrogen binary clathrate hydrates was 27 min in a porous medium with a median pore diameter of 49 Å, which is 6-22 times faster than the tetrahydrofuran-hydrogen binary clathrate hydrates formed in the bulk ice. The clathrate formation time was found to increase with pore size of the porous media. A modified, shrinking core kinetic model was used to calculate the diffusivity of hydrogen in the tetrahydrofuranhydrogen binary clathrate hydrates. Hydrogen diffusivities in the tetrahydrofuran-hydrogen binary clathrate hydrates were found to be on the order of 1O-18-10~19 m2/s and decrease with increasing pore size or clathrate particle size.