Decomposition Kinetics and Recycle of Binary Hydrogen-Tetrahydrofuran Clathrate Hydrate

Decomposition kinetics and recycle of hydrogen-tetrahydrofuran (H-2-THF) clathrate hydrates were investigated with a pressure decay method at temperatures from 265.1 to 273.2 K, at initial pressures from 3.1 to 8.0 MPa, and at stoichiometric THF hydrate concentrations for particle sizes between 250 and 1000 mu m. The decomposition was modeled as a two-step process consisting of H-2 diffusion in the hydrate phase and desorption from the hydrate cage. The adsorption process occurred at roughly two to three times faster than the desorption process, whereas the diffusion process during formation was slightly higher (ca. 20%) than that during decomposition. Successive formation and decomposition cycles showed that occupancy seemed to decrease only slightly with cycling and that there were no large changes in hydrate structure due to cycling. Results provide evidence that the formation and decomposition of H-2 clathrate hydrates occur reversibly and that H-2 clathrate hydrates can be recycled with pressure. (C) 2010 American Institute of Chemical Engineers AIChE J, 57: 265-272, 2011