Dissociation Behavior of Clathrate Hydrates to Ice and Dependence on Guest Molecules

Takeya, Satoshi; Ripmeester, John A.

doi:10.1002/ange.200703718

Cited by 53 publications

(93 citation statements)

References 32 publications

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“…This fact might explain the different degrees of ice-shielding effect between the two systems and thereby explain the observed differences in dissociation rates. These observations indicate that, in addition to the hydrate dissociation rates [13] and the crystal habits of the ice products, [14] the microstructures of self-preserved hydrates depend considerably on the hydrate systems, probably because of differences in the interaction between gas and water molecules. Taken together, these findings pose important implications for elucidating the nature of gas-hydrate dissociation to ice, which is closely related to technologies for controlling hydrate decomposition during industrial processes.…”

Section: à3mentioning

confidence: 93%

Morphological and Compositional Characterization of Self‐Preserved Gas Hydrates by Low‐Vacuum Scanning Electron Microscopy

et al. 2011

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Unequal interactions: A backscattering electron microscopy study reveals that some Kr hydrates can be trapped in ice products during dissociation (see image) whereas no clear evidence of such a phenomenon is found for Ar samples. Also, the texture of ice from Ar‐hydrate decomposition is more cohesive than that observed for Kr samples. The different dissociation behavior between the two systems may be attributed to differences in the interaction between gas and water molecules.

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Section: à3mentioning

confidence: 93%

Morphological and Compositional Characterization of Self‐Preserved Gas Hydrates by Low‐Vacuum Scanning Electron Microscopy

et al. 2011

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“…The ability of clathrate hydrates of some gases to exist at temperatures below the ice melting point outside their stable region has been experimentally observed by numerous researchers (Davidson et al, 1986;Kuhs et al, 2004;Ogienko et al, 2006;Shimada et al, 2005;Stern et al, 2001;Takeya and Ripmeester, 2008;Takeya et al, 2001;Yakushev and Istomin, 1992;Zhang and Rogers, 2008). This anomalous behavior is known as the selfpreservation phenomenon (Yakushev and Istomin, 1992) or the anomalous preservation regime (Stern et al, 2001).…”

Section: Introductionmentioning

confidence: 92%

Stability and growth of gas hydrates below the ice–hydrate–gas equilibrium line on the P–T phase diagram

Melnikov

Nesterov

Reshetnikov

et al. 2010

Chemical Engineering Science

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“…One of the highest concerns is raised by the fact that not all gas hydrates exhibit such a dissociation anomaly [25,26]. There are two commonly formed von Stackelberg structures (sI and sII) when hydrates crystallize; CH 4 and CO 2 hydrates belong to sI and both usually enter the self-preserved state.…”

Section: Self-preservation Of Methane Hydratementioning

confidence: 99%

“…Likewise, some higher hydrocarbons as well as some (partially) fluorinated hydrocarbons show no or only limited self-preservation, both in sI and sII structures [18]. This certainly is not fully understood and so far only treated in a phenomenological way without any satisfactory explanation [25,26]. On the positive side though, it should be noted that most of the prospective natural gas hydrates contained in a sedimentary matrix (that are thought to supply the NGH-based transport chain) consist of methane-rich sI hydrates largely free of higher hydrocarbons, gas compositions for which the existence of the phenomenon of self-preservation is rather likely.…”

Section: Self-preservation Of Methane Hydratementioning

confidence: 99%

Methane Hydrate Pellet Transport Using the Self-Preservation Effect: A Techno-Economic Analysis

et al. 2012

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Within the German integrated project SUGAR, aiming for the development of new technologies for the exploration and exploitation of submarine gas hydrates, the option of gas transport by gas hydrate pellets has been comprehensively re-investigated. A series of pVT dissociation experiments, combined with analytical tools such as x-ray diffraction and cryo-SEM, were used to gather an additional level of understanding on effects controlling ice formation. Based on these new findings and the accessible literature, knowns and unknowns of the self-preservation effect important for the technology are summarized. A conceptual process design for methane hydrate production and pelletisation has been developed. For the major steps identified, comprising (i) hydrate formation; (ii) dewatering; (iii) pelletisation; (iv) pellet cooling; and (v) pressure relief, available technologies have been evaluated, and modifications and amendments included where needed. A hydrate carrier has been designed, featuring amongst other technical solutions a OPEN ACCESSEnergies 2012, 5 2500 pivoted cargo system with the potential to mitigate sintering, an actively cooled containment and cargo distribution system, and a dual fuel engine allowing the use of the boil-off gas. The design was constrained by the properties of gas hydrate pellets, the expected operation on continental slopes in areas with rough seas, a scenario-defined loading capacity of 20,000 m 3 methane hydrate pellets, and safety as well as environmental considerations. A risk analysis for the transport at sea has been carried out in this early stage of development, and the safety level of the new concept was compared to the safety level of other ship types with similar scopes, i.e., LNG carriers and crude oil tankers. Based on the results of the technological part of this study, and with best knowledge available on the alternative technologies, i.e., pipeline, LNG and CNG transportation, an evaluation of the economic competitiveness of the methane hydrate transport technology has been performed. The analysis considers capital investment as well as operational costs and comprises a wide set of scenarios with production rates from 20 to 800 10 and transport distances from 200 to 10,000 km. In contrast to previous studies, the model calculations in this study reveal no economic benefit of methane hydrate transportation versus competing technologies.

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Dissociation Behavior of Clathrate Hydrates to Ice and Dependence on Guest Molecules

Abstract: Selbstschutz: Die Langzeitbeständigkeit von Gashydraten (siehe Bild) jenseits ihrer Stabilitätsgrenzen hängt von der Stärke der Wechselwirkungen zwischen den Gastmolekülen (rot) und Wasser (blau) ab. Dieses Verhalten spiegelt sich in den Dissoziationsdrücken bei 273 K wider.

Cited by 53 publications

References 32 publications

Morphological and Compositional Characterization of Self‐Preserved Gas Hydrates by Low‐Vacuum Scanning Electron Microscopy

Morphological and Compositional Characterization of Self‐Preserved Gas Hydrates by Low‐Vacuum Scanning Electron Microscopy

Stability and growth of gas hydrates below the ice–hydrate–gas equilibrium line on the P–T phase diagram

Methane Hydrate Pellet Transport Using the Self-Preservation Effect: A Techno-Economic Analysis

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