Study on reuse of dry water to store methane in a hydrate form

摘要

Dry water (DW) is a powder composed of hydrophobic silica surrounding tiny water droplets. It's recently demonstrated to be an effective medium for storage methane in a hydrated form. But the recyclability of DW is not so clear at present. Here we used a dedicated pressure cell to form four dry water methane hydrates samples (DW-MH), corresponding to four cycle-types of hydrate formation and dissociation, to investigate the reuse of dry water. The results show that part of water escape from DW and become "free water" after DW-MH is dissociated. The free water is hard to form hydrate during the next cycle of hydrate formation. As a result, the gas storage capacity of DW-MH decreases dramatically as the using times of DW increases.