| 초록 |
A large amount of CH4 gas in the form of solid hydrates naturally deposits in permafrost zone and sea floor sediments around the world. For recovery of CH4 in efficient way, we suggested ‘Swapping process’ to overcome the drawback of conventional recovery methods triggering catastrophic slope failures; external CO2 and N2 molecules in the hydrate deposits replaces the CH4, and consequently CH4 is successfully recovered, maintaining its own structure. Actually, natural gas hydrate is mixed with clay sediment under sea water condition, but the effect of clay sediment on CH4 recovery rate has not yet been reported. In this study, we attempted the recovery of CH4 from the methane hydrate and clay mixture with CO2 under the sea floor conditions. To calculate recovery rate, the replacement of CH4 with CO2 in the hydrate and clay mixture containing 2.7 wt% of NaCl aqueous solution was monitored by gas chromatography and 13C solid-state NMR spectroscopy. The result demonstrates that the higher concentration of clay results in the lower recovery rate. |
