2005 Fiscal Year Final Research Report Summary
Enhancement of clathrate-hydrate formation by the addition of surfactants
| Project/Area Number |
16360109
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Thermal engineering
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| Research Institution | Keio University |
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Principal Investigator |
MORI Yasuhiko Keio University, Faculty of Science and Technology, Professor, 理工学部, 教授 (90051888)
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| Project Period (FY) |
2004 – 2005
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| Keywords | clathrate hydrate / gas hydrate / energy storage and transport / crystal growth / thermal engineering / surfactant / micelle / critical micelle concentration |
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| Research Abstract |
This project aimed to examine the effectiveness of surfactant addition on the formation of a clathrate hydrate in a quiescent liquid-water/guest-gas system, in order to have an insight into the possibility of establishing an efficient, low-cost means of storing natural gas in the form of a hydrate. The project was composed of some specific studies, which are outlined below in order.
1.A series of experimental observations was performed to reveal how the hydrate formation from a hydrofluorocarbon gas, HFC-32 (CH_2F_2), is affected by the addition of sodium dodecyl sulfate (SDS) to an unstirred pool of water in contact with HFC-32 under a constant pressure. The dependency of the rate of hydrate formation (as estimated by the rate of HFC-32 consumption during hydrate formation) on SDS concentration was determined. The surface tension of the aqueous SDS solutions was also measured to determine the SDS-in-water solubility under the hydrate-forming conditions.
2.The surface tension of aqueous solutions of SDS, sodium tetradecyl sulfate (STS) and sodium hexadecyl sulfate (SHS) was measured in a methane atmosphere under the hydrate-forming conditions. The dependency of surface tension on the concentration of each surfactant was determined, which could be a base knowledge for interpreting the behavior of methane-hydrate formation observed in the experiments outlined in item (3).
3.Hydrate-forming experiments were performed, using methane as the guest gas and each of the three sodium alkyl sulfates (SDS,STS and SHS) as the surfactant. The experiments revealed the dependencies of the rate of hydrate formation and the total amount of the formed hydrate on the surfactant concentration.
4.A cold-plate-type device to be hung in the guest-gas phase and dipped in the aqueous phase was constructed for use in the experiments to examine its effect on the hydrate formation rate. These experiments are yet-to-be performed.
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