Marine Biogeochemistry

Subproject B3 Pellet Transport of Natural Gas

Gas hydrate transport in pelletized form utilizing the self preservation effect

Natural gas extracted from clathrate deposits offshore needs to be stored and later transported in a reasonably efficient, inexpensive way. We explore a possibility to utilize a clathrate cage structure as a highly efficient storage medium and the phenomenon of so called “self-preservation” for its stabilization. During the decomposition at the ambient pressure and several degrees below the melting point of ice in the “self-preservation” region, clathrate pellets will be coated by an ice film that is able to retard any further transformation from minutes to weeks/months time scale. In this state, gas hydrates would be transported to costal facilities for further processing.

However, up to now the “self-preservation” phenomenon for pure methane and mixed (CH4 + other gases) hydrates is still not sufficiently understood to be applicable on an industrial scale. By various analytical methods, we plan to explore the most suitable p- T- treatment to obtain a satisfactory degree of preservation and stability of produced pellets. Since the “self-preservation” is a fragile state and might be mechanically destroyed during production and transport phases we attempt to reinforce the ice protective coating with polymer additives.

The successful application of a technology for gas storage and transport based on “self-preserved” hydrates is a challenge from the engineering point of view, as a new line of production technologies must be developed. We search for efficient clathrate synthesis (ice + gas / water + gas / water + gas + polymers) and pelletisation techniques that would allow for mass offshore production. “Self-preserved” clathrates require storage containers that would sustain sub-zero temperatures. Finally new NGH cargo ship designs are necessary for safe clathrate transport to coastal processing facilities. Within subproject B3, all steps of the NGH transport chain are addressed and the competiveness with respect to established gas transport schemes is evaluated.

Literatur

Author

Title

Year

Journal/Proceedings

Reftype

DOI/URL

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The effect of elevated methane pressure on methane hydrate dissociation

2004

American Mineralogist
Vol. 89(8-9), pp. 1192-1201 

article

 

Kuhs, W.F., Genov, G., Staykova, D.K. & Hansen, T.

Ice perfection and onset of anomalous preservation of gas hydrates

2004

Physical Chemistry Chemical Physics
Vol. 6(21), pp. 4917-4920 

article

DOI  

Sloan, E.D.J. & Koh, C.

Clathrate hydrates of natural gases

2008

, pp. 537-628 

inbook

URL 

Stern, L.A., Circone, S., Kirby, S.H. & Durham, W.B.

Temperature, pressure, and compositional effects on anomalous or "self" preservation of gas hydrates

2003

Canadian Journal of Physics
Vol. 81(1-2), pp. 271-283 

article

DOI  

Stern, L.A., Circone, S., Kirby, S.H. & Durham, W.B.

Anomalous preservation of pure methane hydrate at 1 atm

2001

Journal of Physical Chemistry B
Vol. 105(9), pp. 1756-1762 

article

DOI  

Takeya, S., Ebinuma, T., Uchida, T., Nagao, J. & Narita, H.

Self-preservation effect and dissociation rates of CH4 hydrate

2002

Journal of Crystal Growth
Vol. 237, pp. 379-382 

article

 

Takeya, S., Uchida, T., Nagao, J., Ohmura, R., Shimada, W., Kamata, Y., Ebinuma, T. & Narita, H.

Particle size effect of CH4 hydrate for self-preservation

2005

Chemical Engineering Science
Vol. 60(5), pp. 1383-1387 

article

DOI  

Tooru, I., Masahiro, T., Yuichi, K., Kiyoshi, H. & Uchida, K.

Research on Self-preservation of Natural Gas Hydrate Pellet (NGHP)

2006

Mitsui Zosen Technical Review(187), pp. 15-21 

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URL 

Yakushev, V. & VA, I.

Gas-Hydrates Self-Preservation Effect

1992

Physics and Chemistry of Ice, pp. 136-139 

inproceedings