A new clathrate hydrate structure

Gas hydrates, also known as clathrate hydrates, are non-stoichometric crystalline compounds that have an "ice-like" appearance. They occur when water molecules hydrogen bond to form cavities that can be occupied by a gas or volatile liquid. The inclusion of these guest molecules stabilizes the water network. Hydrates are a nuisance to the gas processing industry as they plug pipelines and equipment which can upset daily operations and add unnecessary maintenance costs.In this work, kinetic experiments were performed on a methane-water system in the presence of Antifreeze Proteins (AFP`s) in order to elucidate their effectiveness as a kinetic hydrate inhibitor. The results were compared to experiments done with a classical

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“…This structure was discovered in 1987 by Ripmeester (Ripmeester et. al, 1987 (Ripmeester et. al, 1987).…”

Section: Hydrate Formation and Structurementioning

confidence: 99%

The effect of biological and polymeric inhibitors on methane gas hydrate growth kinetics

Al-Adel

Dick

El-Ghafari

et al. 2008

Fluid Phase Equilibria

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“…However, other hydrocarbons such as ethane (C2H6), propane (C3H8), and isobutane (i-C4H10) may be encaged together with CH4 2) . Three crystallographic structures are known for gas hydrates, structure I (sI), structure II (sII), and structure H (sH) 1), 3) . Both C2H6 hydrate and CH4 hydrate have the sI structure, in which the unit cell consists of 46 H2O molecules (two small cages with twelve pentagonal faces (5 12 ), and six large cages with twelve pentagonal and two hexagonal faces (5 12 6 2 )).…”

Section: Introductionmentioning

confidence: 99%

“…In general, samples of synthesized gas hydrates and natural gas hydrates recovered from sea fl oor contain a certain amount of frozen water 5), 7) . Therefore, the cage occupancy is difficult to estimate from the amounts of water and gas obtained by dissociation of , Hitoshi Shoji 2) , Yasushi Kamata 3), 5) , Takao Ebinuma 3) , Hideo Narita 3) , and Satoshi Takeya CP-MAS 13 C NMR measurements were carried out on mixed gas hydrates containing CH4 _ C2H6. The changes in NMR chemical shift values for CH4 and C2H6 clearly corresponded to the structural changes in the hydrate structure.…”

Section: Introductionmentioning

confidence: 99%

Estimation of Gas Composition and Cage Occupancies in CH4-C2H6 Hydrates by CP-MAS 13C NMR Technique

真人

寛敏

信夫

et al. 2007

J. Jpn. Petrol. Inst.

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13C NMR spectra. The cage occupancies of the small and large cages of the hydrates were estimated from the 13 C NMR spectra on the basis of a statistical thermodynamic model. The large cages were almost fully occupied with guest molecules, whereas small cage occupancy decreased with increasing C2H6 concentration. Therefore, large cages are highly preferentially occupied by C2H6 molecules rather than CH4 molecules.

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“…28 Addition of H 2 S to a mixture of cyclohexane and water actually promotes formation of a cyclohexane clathrate hydrate. 29 Normally cyclohexane is too big to be a suitable guest in a structure II type cage, but H 2 S fills the smaller cavities in the structure stabilizing the clathrate, smaller molecules stabilizing clathrates that wouldn't normally form are referred to as help gases. 30 In methane/H 2 S clathrates H 2 S fills the smaller cavities of the structure I clathrate whilst methane fills the larger cavities.…”

Section: Gas Clathrate Hydratesmentioning

confidence: 99%

Problems Associated with Sour Gas in the Oilfield Industry and Their Solutions

2015

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. (2015) 'The problems associated with sour gas in the oil eld industry and their solutions.', Energy fuels., 29 (8). pp. 4667-4682. Further information on publisher's website:http://dx.doi.org/10.1021/acs.energyfuels.5b00952Publisher's copyright statement:This document is the Accepted Manuscript version of a Published Work that appeared in nal form in Energy Fuels, copyright c 2015 American Chemical Society after peer review and technical editing by the publisher. To access the nal edited and published work see http://dx.doi.org/10.1021/acs.energyfuels.5b00952.Additional information:Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractFossil fuels are still a necessary and important part of modern living, keeping cars running and houses heated for example. As demands have risen and reservoirs of oil and natural gas have depleted, it has become increasingly more important to tap in to fields that were once classified as undesirable. Sour fields, fields high in acidic gases such as hydrogen sulfide and carbon dioxide, are one such option. There are many difficulties and dangers associated with working sour fields, such as toxicity of the sour gases, hydrate formation and corrosion of equipment that have prevented these resources being used in the past. Many varied methods of overcoming these problems have been developed, from removing the sour components to inhibiting their effects. This review highlights the major issues raised by sour fields as well as a wide range of solutions in use today.

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A new clathrate hydrate structure

Cited by 720 publications

References 8 publications

The effect of biological and polymeric inhibitors on methane gas hydrate growth kinetics

The effect of biological and polymeric inhibitors on methane gas hydrate growth kinetics

Estimation of Gas Composition and Cage Occupancies in CH<sub>4</sub>-C<sub>2</sub>H<sub>6</sub> Hydrates by CP-MAS <sup>13</sup>C NMR Technique

Problems Associated with Sour Gas in the Oilfield Industry and Their Solutions

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