2000 Fiscal Year Final Research Report Summary
Formation and dissociation of clathrate hydrates and related heat/mass transfer
| Project/Area Number |
10450088
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B).
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Thermal engineering
|
|---|
| Research Institution | Keio University |
|---|
Principal Investigator |
MORI Yasuhiko h. Keio University, Department of Mechanical Engineering, Professor, 理工学部, 教授 (90051888)
|
|---|
| Project Period (FY) |
1998 – 2000
|
| Keywords | clathrate hydrate / gas hydrate / crystal growth / mass transfer / heat transfer / global warming / energy storage / エネルギー貯蔵 |
|---|
| Research Abstract |
This project has investigated the formation, growth and dissociation of clathrate hydrates on the basis of heat-and mass-transfer science. Major results obtained in the project are summarized below.
(1) The thickness of hydrate films formed at the interface between water and a hydrophobic guest substance both in liquid states was measured, using a laser interferometer. These measurements revealed a strong temperature dependency of the variation in thickness of the films with their age.
(2) Microscopic, cross-sectional observations of hydrate films each formed in a narrow water channel confined by parallel, transparent plates revealed a substantial effect of water shear flow on the surface/internal texture and the thickness of the films.
(3) An analytical model was constructed, which relates the simultaneous heat and mass transfer to/from and across a hydrate film to its thickness.
(4) The observed profiles of sessile drops of a hydrophobic guest substance in water before and after the formation of hydrate films were analyzed to deduce the water-guest interfacial tension. The tension was found to be hardly affected by the prior hydrate formation/dissociation at the drop surfaces.
(5) The behavior of formation and growth, or melting, of a planar hydrate layer from, or into, an aqueous tetrahydrofuran solution having the same composition as that of the hydrate were observed in a one-dimensional heat-transfer system. The behavior was found to be well simulated by a simple heat-transfer analysis, assuming local equilibrium at the hydrate-solution interfaces.
(6) A novel scheme for rapid hydrate formation was proposed, which utilizes water spraying against a cooled metal block in the ambience of a guest gas. The hydrate formation in an experimental system equipped with such a spray/cooler assembly was observed.
|
