Academic literature on the topic 'Hydrogen clathrate hydrate'
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Journal articles on the topic "Hydrogen clathrate hydrate"
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Ahn, Yun-Ho, Byeonggwan Lee, and Kyuchul Shin. "Structural Identification of Binary Tetrahydrofuran + O2 and 3-Hydroxytetrahydrofuran + O2 Clathrate Hydrates by Rietveld Analysis with Direct Space Method." Crystals 8, no. 8 (August 18, 2018): 328. http://dx.doi.org/10.3390/cryst8080328.
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The structural determination of clathrate hydrates, nonstoichiometric crystalline host-guest materials, is challenging because of the dynamical disorder and partial cage occupancies of the guest molecules. The application of direct space methods with Rietveld analysis can determine the powder X-ray diffraction (PXRD) patterns of clathrates. Here, we conducted Rietveld analysis with the direct space method for the structural determination of binary tetrahydrofuran (THF) + O2 and 3-hydroxytetrahydrofuran (3-OH THF) + O2 clathrate hydrates in order to identify the hydroxyl substituent effect on interactions between the host framework and the cyclic ether guest molecules. The refined PXRD results reveal that the hydroxyl groups are hydrogen-bonded to host hexagonal rings of water molecules in the 51264 cage, while any evidences of hydrogen bonding between THF guests and the host framework were not observed from PXRD at 100 K. This guest-host hydrogen bonding is thought to induce slightly larger 512 cages in the 3-OH THF hydrate than those in the THF hydrate. Consequently, the disorder dynamics of the secondary guest molecules also can be affected by the hydrogen bonding of larger guest molecules. The structural information of binary clathrate hydrates reported here can improve the understanding of the host-guest interactions occurring in clathrate hydrates and the specialized methodologies for crystal structure determination of clathrate hydrates.
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Hashimoto, Shunsuke, Takaaki Tsuda, Kyohei Ogata, Takeshi Sugahara, Yoshiro Inoue, and Kazunari Ohgaki. "Thermodynamic Properties of Hydrogen + Tetra-n-Butyl Ammonium Bromide Semi-Clathrate Hydrate." Journal of Thermodynamics 2010 (December 10, 2010): 1–5. http://dx.doi.org/10.1155/2010/170819.
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Thermodynamic stability and hydrogen occupancy on the hydrogen + tetra-n-butyl ammonium bromide semi-clathrate hydrate were investigated by means of Raman spectroscopic and phase equilibrium measurements under the three-phase equilibrium condition. The structure of mixed gas hydrates changes from tetragonal to another structure around 95 MPa and 292 K depending on surrounding hydrogen fugacity. The occupied amount of hydrogen in the semi-clathrate hydrate increases significantly associated with the structural transition. Tetra-n-butyl ammonium bromide semi-clathrate hydrates can absorb hydrogen molecules by a pressure-swing without destroying the hydrogen bonds of hydrate cages at 15 MPa or over.
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BELOSLUDOV, V. R., O. S. SUBBOTIN, R. V. BELOSLUDOV, H. MIZUSEKI, Y. KAWAZOE, and J. KUDOH. "THERMODYNAMICS AND HYDROGEN STORAGE ABILITY OF BINARY HYDROGEN + HELP GAS CLATHRATE HYDRATE." International Journal of Nanoscience 08, no. 01n02 (February 2009): 57–63. http://dx.doi.org/10.1142/s0219581x0900589x.
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Storage of hydrogen as hydrogen hydrate is a promising alternative technology to liquefied hydrogen at cryogenic temperatures or compressed hydrogen at high pressures. In this paper, computer simulation is performed based on the solid solution theory of clathrates of van der Waals and Platteeuw with some modifications that include in particular the account of multiple cage occupancies and host relaxation. The quasiharmonic lattice dynamics method employed here gives the free energy of clathrate hydrate to first order in the anharmonicity of intermolecular potential and permits to take into account quantum zero-point vibration of host lattice and hydrogen in the cages. It is employed to study the thermodynamic functions of binary (mixed) H 2– CH 4 hydrates of cubic structure II (sII) and hexagonal structure H (sH). It is shown that at divariant equilibrium "gas phase–gas hydrate" with increasing pressure the filling of large cavities by hydrogen proceeds gradually from single filling to the maximal number of hydrogen molecules in clusters included in large cages (four in sII and five in sH) preserving stability of the hydrogen–methane hydrates sII and sH. The results show that mass fraction of hydrogen in the mixed sH hydrate is significantly lower than in the mixed sII hydrate. Pressure of monovariant equilibrium " IceI h–gas phase–mixed sII hydrate" with increasing methane concentration in the gas phase lowers in comparison with the pressure of pure hydrogen hydrate formation. For the mixed hydrogen + methane sH hydrates, it was demonstrated that thermodynamic stability depends on the filling degree of small cavities by methane molecules and stability area shifts to lower pressure with increasing filling.
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Ghaani, Mohammad Reza, Satoshi Takeya, and Niall J. English. "Hydrogen Storage in Propane-Hydrate: Theoretical and Experimental Study." Applied Sciences 10, no. 24 (December 15, 2020): 8962. http://dx.doi.org/10.3390/app10248962.
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There have been studies on gas-phase promoter facilitation of H2-containing clathrates. In the present study, non-equilibrium molecular dynamics (NEMD) simulations were conducted to analyse hydrogen release and uptake from/into propane planar clathrate surfaces at 180–273 K. The kinetics of the formation of propane hydrate as the host for hydrogen as well as hydrogen uptake into this framework was investigated experimentally using a fixed-bed reactor. The experimental hydrogen storage capacity propane hydrate was found to be around 1.04 wt% in compare with the theoretical expected 1.13 wt% storage capacity of propane hydrate. As a result, we advocate some limitation of gas-dispersion (fixed-bed) reactors such as the possibility of having un-reacted water as well as limited diffusion of hydrogen in the bulk hydrate.
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Mao, W. L. "Hydrogen Clusters in Clathrate Hydrate." Science 297, no. 5590 (September 27, 2002): 2247–49. http://dx.doi.org/10.1126/science.1075394.
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Ghaani, Mohammad Reza, Judith M. Schicks, and Niall J. English. "A Review of Reactor Designs for Hydrogen Storage in Clathrate Hydrates." Applied Sciences 11, no. 2 (January 6, 2021): 469. http://dx.doi.org/10.3390/app11020469.
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Clathrate hydrates are ice-like, crystalline solids, composed of a three-dimensional network of hydrogen bonded water molecules that confines gas molecules in well-defined cavities that can store gases as a solid solution. Ideally, hydrogen hydrates can store hydrogen with a maximum theoretical capacity of about 5.4 wt%. However, the pressures necessary for the formation of such a hydrogen hydrate are 180–220 MPa and therefore too high for large-scale plants and industrial use. Thus, since the early 1990s, there have been numerous studies to optimize pressure and temperature conditions for hydrogen formation and storage and to develop a proper reactor type via optimisation of the heat and mass transfer to maximise hydrate storage capacity in the resulting hydrate phase. So far, the construction of the reactor has been developed for small, sub-litre scale; and indeed, many attempts were reported for pilot-scale reactor design, on the multiple-litre scale and larger. The purpose of this review article is to compile and summarise this knowledge in a single article and to highlight hydrogen-storage prospects and future challenges.
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Mulder, Fokko M., Marnix Wagemaker, Lambert van Eijck, and Gordon J. Kearley. "Hydrogen in Porous Tetrahydrofuran Clathrate Hydrate." ChemPhysChem 9, no. 9 (June 23, 2008): 1331–37. http://dx.doi.org/10.1002/cphc.200700833.
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Di Profio, Pietro, Simone Arca, Raimondo Germani, and Gianfranco Savelli. "Novel Nanostructured Media for Gas Storage and Transport: Clathrate Hydrates of Methane and Hydrogen." Journal of Fuel Cell Science and Technology 4, no. 1 (April 6, 2006): 49–55. http://dx.doi.org/10.1115/1.2393304.
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In the last years the development of fuel cell (FC) technology has highlighted the correlated problem of storage and transportation of gaseous fuels, particularly hydrogen and methane. In fact, forecasting a large scale application of the FC technology in the near future, the conventional technologies of storage and transportation of gaseous fuels will be inadequate to support an expectedly large request. Therefore, many studies are being devoted to the development of novel efficient technologies for gas storage and transport; one of those is methane and hydrogen storage in solid, water-based clathrate hydrates. Clathrate hydrates (CH) are nonstoichiometric, nanostructured complexes of small “guest” molecules enclosed into water cages, which typically form at relatively low temperature-high pressure. In nature, CH of natural gas represent an unconventional and unexploited energy source and methane hydrate technology is already applied industrially. More recently, striking literature reports showed a rapid approach to the possibility of obtaining hydrogen hydrates at room temperature/mild pressures. Methane hydrate formation has been shown to be heavily promoted by some chemicals, notably amphiphiles. Our research is aimed at understanding the basic phenomena underlying CH formation, with a goal to render hydrate formation conditions milder, and increase the concentration of gas within the CH. In the present paper, we show the results of a preliminary attempt to relate the structural features of several amphiphilic additives to the kinetic and thermodynamic parameters of methane hydrate formation—e.g., induction times, rate of formation, occupancy, etc. According to the present study, it is found that a reduction of induction time does not necessarily correlate to an increase of the formation rate and occupancy, and so on. This may be related to the nature of chemical moieties forming a particular amphiphile (e.g., the hydrophobic tail, head group, counterion, etc.). Moreover, a chemometric approach is presented which is aimed at obtaining information on the choice of coformers for H2 storage in hydrates at mild pressures and temperatures.
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Alavi, Saman, and John A Ripmeester. "Hydrogen-Gas Migration through Clathrate Hydrate Cages." Angewandte Chemie International Edition 46, no. 32 (August 13, 2007): 6102–5. http://dx.doi.org/10.1002/anie.200700250.
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Alavi, Saman, and John A Ripmeester. "Hydrogen-Gas Migration through Clathrate Hydrate Cages." Angewandte Chemie 119, no. 32 (August 13, 2007): 6214–17. http://dx.doi.org/10.1002/ange.200700250.
Full textDissertations / Theses on the topic "Hydrogen clathrate hydrate"
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Teeratchanan, Pattanasak. "First-principles studies of gas hydrates and clathrates under pressure." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/31359.
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Gas hydrates are molecular host-guest mixtures where guest gas species are encapsulated in host water networks. They play an important role in gas storage in aqueous environments at relatively low pressures, and their stabilities are determined by weak interactions of the guest species with their respective host water frameworks. Thus, the size and the amount of the guest species vary, depending on the size of the empty space provided by the host water structures. The systems studied here are noble gas (He, Ne, Ar) and diatomic (H2) hydrates. Because of the similarity of the guests' sizes between the noble gases and the di-atomic gases, the noble gas hydrates act as simple models for the di-atomic gas hydrates. For example, He, Ne and H2 have approximately the same size. Density functional theory calculations are used to obtain the ground state formation enthalpies of each gas hydrate, as a function of host network, guest stoichiometry, and pressure. Dispersion effects are investigated by comparing various dispersion corrections in the exchange-correlation functionals (semi-local PBE, semi-empirical D2 pair correction, and non-local density functionals i.e. vdW-DF family). Results show that the predicted stability ranges of various phases agree qualitatively, although having quantitative difference, irrespective of the methods of the dispersion corrections in the exchange-correlation functionals. Additionally, it is shown in gas-water dimer interaction calculations that all DFT dispersion-corrected functionals overbind significantly than the interaction acquired by the coupled-cluster calculations, at the CCSD(T) level, which is commonly accepted to provide the most accurate estimation of the actual interaction energy. This could lead to an overestimation of the stability of the hydrate mixtures. Further study in the gas-water cluster indicates that less overbinding effect is found in the cluster than in the dimer. This implies that the overbinding energy caused by DFT might become less pronounce in the solid phase. Graph invariant topology and a program based on a graph theory are used to assign protons based on the 'ice rule' to fulfill the incomplete experimental structural data such as unknown/unclear positions of protons in the host water lattices. These methods help constructing host water networks for computational calculations. Several configurations of the host water structures are tested. Those configurations having lowest enthalpies are used as the host water networks in this research. Furthermore, the enthalpic spread between the configurations having the highest and the lowest enthalpy in the pure water ice network is very small (about 10 meV per water molecule). Nevertheless, it is still unclear to conclude that this protonic effect is also trivial in the gas-water compound. Therefore, this study also calculates the enthalpies of the gas-water mixtures having various proton configurations in the host water networks. Results indicate that very small enthalpic distributions among the proton configurations are found in the compounds as well. Furthermore, the enthalpic spread is almost constant as pressure increases. This suggests there is no pressure effect in the enthalpy gap amoung the proton distributions in both pure water ice and the gas-water compounds. Predicted stable phases for the noble gas compound systems are based on four host water networks, namely, ice Ih, II and Ic, and the novel host water network S!. The He-water system adopts ice Ih, II and Ic network upon increasing pressure. In the Ne-water system, a phase sequence of Sx/ice-Ih, II and Ic with a competitive hydrate phase in the S! host network at very low pressure is found. This is similar to the phase evolution of the H2-water system. For the Ar-water mixture, only a partially occupied hydrate in the Sx host network is found stable. This Sx phase becomes metastable if taking the traditional clathrates (sI and sII) into account. This result agrees very well with the experiment suggesting only two-third filling is found the large guest gases i.e. CO2. For the diatomic guest gas compound systems, the traditional clathrate structure (sII) that found to be existed experimentally in the H2-H2O system is also included in this study together with those four host water networks. Predicted phase stability sequence as elevated pressure is as follows: Sx, ice-Ih, II and Ic. This computationally prediction agrees very well with experiment. Results in this work suggest that the compound based on the traditional clathrate structure II (sII) host water framework is found to be metastable with respect to the decomposition constituents - in this case, they are pure water ice and the S!. The metastability of the hydrogen hydrates based on the sII structure might due to zero-point motions or other dynamic/entropic mechanisms uncovered in this research. Dynamic studies concerning the transition states of the hydrogen guest molecules in three competitive phases at very low pressure (less than 10 kbar), based on Sx, ice-Ih, and ice-II host water network, are considered. The energy barriers required by the hydrogen guest molecules in those three host frameworks are calculated by using Nudged Elastic Band (NEB) method. Results suggest that the hydrogen molecules are more mobile in the Sx than the other two host structures significantly. In the S! host water network, the energy barrier is about 25 meV/hydrogen molecule. This energy is about the room temperature suggesting that the hydrogen guest molecules are easily mobile in the Sx host water network if there is an empty site adjacent to them.
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Donnelly, Mary-Ellen. "Neutron diffraction of hydrogen inclusion compounds under pressure." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/31471.
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When ice is compressed alongside a gas, crystalline 'host - guest' inclusion compounds known as gas clathrate hydrates form. These compounds are of interest not only for their environmental and possible technological impact as gas storage and separation materials, but also for their ability to probe networks not readily adopted by the pure `host' water molecules, and to study the interactions between water and gas molecules. Despite the pressure dependent crystal structures being fully determined for a large variety of `guest' gas species there is still relatively little known about the crystal structures in small guest gas systems such as H2 hydrate. The majority of structural studies have been done with x-ray diffraction and report a number of conflicting structures or hydrogen contents for the four known stable phases (sII, C0, C1 and C2). As this is a very hydrogen rich system the most ideal method to study the structure is neutron diffraction, which is able to fully determine the location of the hydrogen atoms within the structure and would allow a direct measurement of any hydrogen ordering within the host structure and the H2 content. In this work the phase diagram of the deuterated analogue of the H2-H2O system is explored at low pressures (below 0.3 GPa) with neutron diffraction. In the pressure/temperature region where the sII phase is known to be stable, two metastable phases were observed between the formation of sII from ice Ih and that this transition sequence occurred in line with Ostwald's Rule of Stages. One of these metastable phases was the C0 phase known to be stable in the H2-H2O system above 0.5 GPa, and the other is a new structure not previously observed in this system and is dubbed in this work as C-1 . Prior to this work the C0 phase has been reported with various structures that were determined with x-ray diffraction, and here the crystal structure and H2 content at low pressure are determined with neutron diffraction. The C0 phase was found to form a similar host structure to those of the previous studies with spiral guest sites but is best described with highly mobile H2 guests and a higher symmetry space group which make it the same structure as the spiral hydrate structure (s-Sp) recently observed in the CO2 hydrate system. In addition to this structure being determined at pressure a sample of C0 was also recovered to ambient pressure at low temperature and its structure/H2 content is presented as it was warmed to decomposition. The crystal structure of the C-1 phase was determined to be similar to ice Ih and a sample was recovered to ambient pressure to study its decomposition behaviour. Evidence for a similar structure in the helium hydrate system at low pressure is also reported here. This work was then extended to higher pressures with the recent developments of a hydrogen-compatible gas loader and large-volume diamond anvil cells. Several test experiments on gas-loaded Paris-Edinburgh presses are described on systems that are similar to hydrogen-water like urea-hydrogen and neon-water. And a further preliminary high pressure study on the deuterated analogue of the H2- H2O system in a diamond anvil cell between 3.6 and 28 GPa shows decomposition behaviour as pressure was increased.
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Izquierdo, Ruiz Fernando. "Clatratos Hidratos de Gas en Condiciones Extremas." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS187/document.
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Ce document contient un rapport scientifique résultant de plus de quatre années de recherche théorique et expérimentale sur un type particulier de systèmes physico-chimiques appelés hydrates de clathrates de gaz. Ces systèmes sont des composés d'inclusion constitués d'un cadre aqueux tridimensionnel contenant des molécules de gaz avec de faibles moments dipolaires dans leurs cavités. Les hydrates de clathrate de gaz sont très importants dans une grande variété de domaines scientifiques liés aux sciences de la vie ou à la planétologie, et ils sont également considérés comme une ressource naturelle principale pour l'industrie de l'énergie. Habituellement, les hydrates de clathrate de gaz nécessitent une pression élevée et une température basse pour être thermodynamiquement stables. En fonction de ces conditions, différentes phases ont été détectées, les plus courantes étant les structures cubiques sI et sII, la sH hexagonale et la structure de glace remplacée orthorhombique (FIS). Notre étude a considérablement progressé dans la connaissance du comportement du méthane et des hydrates de clathrate de dioxyde de carbone dans différentes conditions de pression et de température. En particulier, nous avons contribué à : (i) la détermination et la compréhension des régions thermodynamiques de stabilité, (ii) la caractérisation d'une structure haute pression controversée et (iii) la mise en place d'un nouvel équipement expérimental pour les mesures Raman dans une gamme de pression jusqu'à 1 GPa [...]This document contains a scientific report resulting from more than four years of theoretical and experimental research on a particular kind of physicochemical systems called gas clathrate hydrates. These systems are inclusion compounds constituted by a three dimensional water framework hosting gas molecules with low dipolar moments in its cavities. Gas clathrate hydrates are very important in a great variety of scientific fields related to life sciences or planetology, and they are also considered as a main natural resource for the energy industry. Usually, gas clathrate hydrates need high pressure and low temperature to be thermodynamically stable. Depending on these conditions, differentphases have been detected being the most common ones the cubic structuressI and sII, the hexagonal sH, and the orthorhombic Filled Ice Structure(FIS). Our study has substantially advanced in the knowledge of the behaviorof methane and carbon dioxide clathrate hydrates under different pressure andtemperature conditions. In particular, we have contributed to: (i) the determination and understanding of stability thermodynamic regions, (ii) the characterizationof a controversial high-pressure structure, and (iii) setting up a new experimental equipment for Raman measurements in a pressure range up to 1 GPa [...]
Este documento contiene el informe científico resultante después de más de cuatro años de investigación teórica y experimental sobre un tipo particular de sistemas físico-químicos llamados clatratos hidratos de gas. Estos sistemas son compuestos de inclusión constituidos por un armazón tridimensional de agua que aloja en sus cavidades moléculas de gas con momentos dipolares bajos.Los clatratos hidratos de gas son muy importantes en una gran variedad de campos científicos relacionados con las ciencias de la vida o la planetología, y también se consideran como uno de los principales recursos naturales para la industria energética. Por lo general, los clatratos hidratos de gas necesitan alta presión y baja temperatura para ser termodinámicamente estables.Dependiendo de estas condiciones, se han detectado diferentes fases siendo las más comunes las estructuras cúbicas sI y sII, hexagonal sH y la estructura ortorrómbica de hielo relleno (FIS). Nuestro estudio ha avanzado sustancialmente en el conocimiento del comportamiento de los clatratos hidratos de metano y dióxido de carbono en diferentes condiciones de presión y temperatura, proporcionando (i) regiones termodinámicas de estabilidad, (ii) la caracterización de una estructura de alta presión controvertida y (iii) un nuevo equipo experimental para mediciones Raman en un rango de presión de hasta 1 GPa [...]
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Pefoute, Takom Eric William. "Vers une meilleure compréhension du stockage de l'Hydrogène dans les clathrate hydrates : analyse de leur dynamique par simulation de dynamique moléculaire et par diffusion quasi élastique de neurtrons." Thesis, Bordeaux 1, 2010. http://www.theses.fr/2010BOR14049/document.
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La disparition attendue des combustibles fossiles dans un avenir proche est l'un des grands défis de ce siècle auquel nous devons faire face. Pour cela, il serait judicieux de transférer l’énergie primaire utilisée aujourd'hui en énergies renouvelables. Le secteur des transports est l'un des plus concernés par cette problématique. Une application dans ce secteur nécessite de nombreux travaux de recherche et c'est dans ce contexte que le stockage de l'hydrogène à l'intérieur des clathrate hydrates a été entrepris au cours de mon programme de recherche doctoral. Cette étude avait pour objectif d’étudier les interactions hôte-invité (dynamique) dans les clathrates hydrates et s’est étendue de la synthèse de clathrates hydrates jusque l’insertion de l'hydrogène en leur sein. Cette étude a été faite à la fois d’un point de vue expérimental et théorique : des simulations de Dynamique Moléculaire (MD) ont été utilisées afin de guider l’interprétation d’expériences de Diffusion incohérente Quasi Elastique des Neutrons (QENS). Dans un premier temps, nous avons développé cette approche méthodologique en étudiant la dynamique du clathrate hydrate de bromométhane, système prototype. Dans un deuxième temps, nous avons appliqué cette approche multi-technique à l'étude de clathrate hydrates impliqués dans la problématique du stockage d'hydrogène. Pour cela, nous avons étudié le clathrate hydrate de tétrahydrofurane (THF), utilisé comme sous-structure hôte au stockage d'hydrogène. Un dispositif expérimental original a été développé pour la préparation d'un hydrate clathrate binaires H2-THF. L’analyse des expériences de diffusion neutronique effectuée sur ce clathrate binaire a révélé l’existence de mouvements diffusifs localisés des molécules d’hydrogène à l’intérieur des cagesThe expected disappearance of fossil fuels in the near future is one of the major challenges of this century which we need to face up and it is necessary to anticipate it. For that, it will be convenient that we have begun the primary energy transfer used today to renewable energy. The sector of transport is one of the most concerned by these renewable energies. An application in this sector would require numerous research works and it is in this context that the hydrogen storage inside the clathrate hydrates has been undertaken during my PhD. This work aimed at investigating the host-guest interactions (dynamics) of clathrate hydrates and ranged from the synthesis of clathrate hydrates to the insertion of hydrogen within them. This study has been done both from experimental and theoretical point of view. Molecular Dynamics (MD) simulations were used to guide the interpretation of incoherent Quasi-Elastic Neutron Scattering (QENS) experiments. At first, we developed a methodology combining MD and QENS to investigate the dynamics of bromomethane clathrate hydrate, a prototypical system. Having validated the multi-technique approach, the methodology has been applied to investigate clathrate hydrates involved in the hydrogen storage problematic. In this issue, the tetrahydrofuran (THF) clathrate hydrate, used as host sub-structure for storing hydrogen, has been studied. An original experimental set-up has been developed for the preparation of a binary H2-THF clathrate hydrate. The analysis of QENS experiments performed on this binary clathrate hydrate revealed the existence of localized translational motion of hydrogen molecules within the clathrate cages
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Schaack, Sofiane. "Nuclear quantum effects in hydrated nanocrystals." Electronic Thesis or Diss., Sorbonne université, 2019. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2019SORUS370.pdf.
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La nature quantique des noyaux produit des comportements inattendus et souvent paradoxaux. Du fait de sa légèreté, l'hydrogène est le candidat le plus susceptible de présenter de tels comportements. Nous avons étudié trois systèmes hydratés dont les mécanismes sont déterminés par les propriétés quantiques des protons (NQEs) : la Brucite (Mg(OH)2), l'hydrate de méthane (CH4-H2O) et l'hydroxyde de sodium (NaOH). Au sein des Brucites coexistent deux effets en compétition : un mécanisme de réorientation thermiquement activé, et un processus de dissociation déclenché par les NQEs. Ces deux effets s'opposent sous l’augmentation de la pression, entraînant l'existence d'un point de pression favorisant la diffusion des protons à mesure que se forme un plan d'hydrogène "quantique" quasi 2D. Sous pression, l’hydrate de méthane présentent une augmentation des interactions entre le réseau d’eau et les molécules de méthane qui y sont enfermées. Contrairement à la glace, la transition de symétrisation des liaisons hydrogène ne change pas par substitution isotopique du fait de la délocalisation du proton. Celle-ci déclenche également une transition vers une nouvelle phase, stable jusqu'à des pressions jamais atteintes par tout hydrate connu à ce jour. La soude présente une transition de phase en-dessous de la température ambiante et à pression ambiante uniquement dans sa version deutérée. Cet effet isotopique s'explique par la délocalisation quantique et par l'importance de l'énergie de point-zéro du proton par rapport au deutéron. Étonnement la substitution isotopique change la transition induite par la température dans NaOD en une transition déclenchée par la pression dans NaOHThe quantum nature of nuclei yields unexpected and often paradoxical behaviors. Due to the lightness of its nucleus, the hydrogen is a most likely candidate for such effects. During this thesis, we focus on complexe hydrated systems, namely, the brucite minerals (Mg(OH)2), the methane hydrate (CH4-H2O) and the sodium hydroxide (NaOH), which display complex mechanisms driven by the proton quantum properties. Brucite exhibits the coexistence of thermally activated hopping and quantum tunneling with opposite behaviors as pressure is increased. The unforeseen consequence is a pressure sweet spot for proton diffusion. Simultaneously, pressure gives rise to a «quantum» quasi two-dimensional hydrogen plane, non-trivially connected with proton diffusion. Upon compression, methane hydrate displays an important increase of the inter-molecular interactions between water and enclosed methane molecules. In contrast with ice, the hydrogen bond transition does not shift by H/D isotopic substitution. This is explained by an important delocalization of the proton which also triggers a transition toward a new MH-IV methane hydrate phase, stable up to 150 GPa which represents the highest pressure reached to date by any hydrate. Sodium hydroxide has a phase transition below room temperature at ambient pressure only in its deuterated version. This radical isotope effect can be explained by the quantum delocalization of the proton as compared with deuteron shifting the temperature-induced phase transition of NaOD towards a pressure-induced one in NaOH
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Strobel, Timothy A., Yongkwan Kim, Carolyn A. Koh, and E. Dendy Sloan. "CLATHRATES OF HYDROGEN WITH APPLICATION TOWARDS HYDROGEN STORAGE." 2008. http://hdl.handle.net/2429/1128.
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In the current work we present a significant advancement in the area of hydrogen storage in clathrates: hydrogen storage from both enclathrated molecular hydrogen as well as storage from the clathrate host lattice. We have investigated the hydrogen storage potential in all of the common clathrate hydrate structures with techniques such as gas evolution, X-ray / neutron diffraction, and NMR / Raman spectroscopy. We have determined that the common clathrate structures may not suffice as H2 storage materials, although these findings will aid in the design and production of enhanced hydrogen storage materials and in the understanding of structure-stability relations of guest-host systems. In view of current storage limitations, we propose a novel chemical – clathrate hybrid hydrogen storage concept that holds great promise for future materials.
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Kawamura, Taro, Michika Ohtake, Yoshitaka Yamamoto, and Satoru Higuchi. "HYDROGEN ABSORPTION BEHAVIOR OF ORGANIC-COMPOUND CLATHRATE HYDRATES." 2008. http://hdl.handle.net/2429/1400.
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The hydrogen absorption behavior of organic-compound clathrate hydrates was investigated using five kinds of organic compounds as well as tetrahydrofuran (THF). These hydrates were pressurized by hydrogen, and Raman analysis, the determination of the amount of hydrogen and calorimetric measurement were carried out. The Raman results show that the samples investigated in this work formed binary clathrate hydrate of hydrogen and each organic compound. The organic-compound clathrate hydrates presented similar performances to that of THF clathrate hydrate regarding hydrogen absorption and heat of dissociation. These results suggested that the organic compounds investigated in this work may become alternatives to THF.
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Okuchi, Takuo, Igor L. Moudrakovski, and John A. Ripmeester. "IN SITU NMR STUDIES OF HYDROGEN STORAGE KINETICS AND MOLECULAR DIFFUSION IN CLATHRATE HYDRATE AT ELEVATED HYDROGEN PRESSURES." 2008. http://hdl.handle.net/2429/1096.
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Clathrate hydrates can be reasonable choices for high-density hydrogen storage into compact host media, which is an essential task for hydrogen-based future society. However, conventional storage scheme where aqueous solution is frozen with hydrogen gas was impractically slow for practical use. Here we propose a much faster scheme where hydrogen gas was directly charged into hydrogen-free, crystalline hydrate powders. The storage kinetics was observed in situ by nuclear magnetic resonance (NMR) spectroscopy in a pressurized tube cell. At pressures up to 20 MPa the storage was complete within 80 minutes, as observed by growth of stored-hydrogen peak into the hydrate. Since the rate-determining step of current storage scheme is body diffusion of hydrogen within the crystalline hydrate media, we have measured the diffusion coefficient of hydrogen molecules using the pulsed field gradient NMR method. The results show that at temperatures down to 250 K the stored hydrogen is highly mobile, so that the powdered hydrate media should work well even in cold environments. Compared with more prevailing hydrogen storage media such as metal hydrides, the clathrate hydrate could offer even more advantages: It is free from hydrogen embrittlement, more chemically durable, more environmentally benign, as well as economically quite affordable.
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Chapoy, Antonin, Ross Anderson, and Bahman Tohidi. "EFFECT OF CLATHRATE STRUCTURE AND PROMOTER ON THE PHASE BEHAVIOUR OF HYDROGEN CLATHRATES." 2008. http://hdl.handle.net/2429/1385.
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Hydrogen is currently considered by many as the “fuel of the future”. It is particularly favoured as a replacement for fossil fuels due to its clean-burning properties; the waste product of combustion being water. While hydrogen is relatively easy to produce, there is currently a lack of practical storage methods for molecular H2, and this is greatly hindering the use of hydrogen as a fuel. Gases are normally stored in vessels under only moderate pressures and in liquid form where possible, which yields the highest energy density. However, to store reasonable quantities of hydrogen in similar volume containers, cryogenic temperatures or extreme pressure are required. Many potential hydrogen storage technologies are currently under investigation, including adsorption on metal hydrides, nanotubes and glass microspheres, and the chemical breakdown of compounds containing hydrogen to release H2. Recent studies have sparked interest in hydrates as a potential hydrogen storage material. The molecular storage of hydrogen in clathrate hydrates could offer significant benefits with regard to ease of formation/regeneration, cost and safety, as compared to other storage materials currently under investigation. Here, we present new experimental hydrate stability data for sII forming hydrogen–water (up to pressures of 180 MPa) and hydrogen–water–tetrahydrofuran systems, the structure-H forming hydrogen–water–methyclycohexane system, and semi-clathrate forming hydrogen–water–tetra-n-butyl ammonium bromide/tetra–n-butyl ammonium fluoride systems.
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Strobel, Timothy A., Carolyn A. Koh, and E. Dendy Sloan. "RAMAN SPECTROSCOPIC STUDIES OF HYDROGEN CLATHRATE HYDRATES." 2008. http://hdl.handle.net/2429/1145.
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Raman spectroscopic measurements of various hydrogen bearing clathrate hydrates have been performed under high (< 1cm-1) and low resolution (>2 cm-1) conditions. Raman bands for hydrogen in most common clathrate hydrate cavities have been assigned. Unlike most clathrate hydrate guests, the general observation is no longer valid that the larger the clathrate cavity in which a guest resides, the lower the vibrational frequency. This is rationalized by the multiple hydrogen occupancies in larger clathrate cavities. Both the roton and vibron bands for hydrogen clathrates illuminate interesting quantum dynamics of the enclathrated hydrogen molecules. At 77K, the progression from ortho to para H2 occurs over a relatively slow time period (days). The para contribution to the roton region of the spectrum exhibits the triplet splitting also observed in solid para H2. The complex vibron region of the Raman spectrum has been interpreted by observing the change in population of these bands with temperature and with isotopic substitution by deuterium. Raman spectra from H2 and D2 hydrates suggest that the occupancy patterns between the two hydrates are analogous. The Raman measurements demonstrate that this is an effective and convenient method to determine the relative occupancy of hydrogen molecules in different clathrate cavities.
Book chapters on the topic "Hydrogen clathrate hydrate"
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Ocampo, J. "Hydrogen Bonds Reorganisation during Clathrate Hydrate Growth in Hexagonal Ice." In Hydrogen Bond Networks, 389–93. Dordrecht: Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-015-8332-9_35.
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Shariati, Alireza, Sona Raeissi, and Cor J. Peters. "Clathrate Hydrates." In Handbook of Hydrogen Storage, 63–79. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2010. http://dx.doi.org/10.1002/9783527629800.ch3.
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Sluiter, Marcel H. F., Rodion V. Belosludov, Amit Jain, Vladimir R. Belosludov, Hitoshi Adachi, Yoshiyuki Kawazoe, Kenji Higuchi, and Takayuki Otani. "Ab Initio Study of Hydrogen Hydrate Clathrates for Hydrogen Storage within the ITBL Environment." In Lecture Notes in Computer Science, 330–41. Berlin, Heidelberg: Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/978-3-540-39707-6_27.
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Erwin Eka Putra, Andi, Shinfuku Nomura, Shinobu Mukasa, and Hiromichi Toyota. "Hydrogen Production by Reforming Clathrate Hydrates Using the in-Liquid Plasma Method." In Progress in Sustainable Energy Technologies: Generating Renewable Energy, 499–507. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-07896-0_30.
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Bunker, Bruce C., and William H. Casey. "Solvated Ions in Water." In The Aqueous Chemistry of Oxides. Oxford University Press, 2016. http://dx.doi.org/10.1093/oso/9780199384259.003.0009.
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In most undergraduate chemistry classes, students are taught to consider reactions in which cations and anions dissolved in water are depicted as isolated ions. For example, the magnesium ion is depicted as Mg2+, or at best Mg2+(aq). For anions, these descriptions may be adequate (if not accurate). However, for cations, these abbreviations almost always fail to describe the critical chemical attributes of the dissolved species. A much more meaningful description of Mg2+ dissolved in water is [Mg(H2O)6]2+, because Mg2+ in water does not behave like a bare Mg2+ ion, nor do the waters coordinated to the Mg2+ behave anything like water molecules in the bulk fluid. In many respects, the [Mg(H2O)6]2+ ion acts like a dissolved molecular species. In this chapter, we discuss the simple solvation of anions and cations as a prelude to exploring more complex reactions of soluble oxide precursors called hydrolysis products. The two key classes of water–oxide reactions introduced here are acid–base and ligand exchange. First, consider how simple anions modify the structure and properties of water. As discussed in Chapter 3, water is a dynamic and highly fluxional “oxide” containing transient rings and clusters based on tetrahedral oxygen anions held together by linear hydrogen bonds. Simple halide ions can insert into this structure by occupying sites that would normally be occupied by other water molecules because they have radii (ranging from 0.13 to 0.22 nm in the series from F− to I−) that are comparable to that of the O2− ion (0.14 nm). Such substitution is clearly seen in the structures of ionic clathrate hydrates, where the anion can replace one and sometimes even two water molecules. Larger anions can also replace water molecules within clathrate hydrate cages. For example, carboxylate hydrate structures incorporate the carboxylate group within the water framework whereas the hydrophobic hydrocarbon “tails” occupy a cavity within the water framework, as in methane hydrate (see Chapter 3). Water molecules form hydrogen bonds to dissolved halide ions just as they can to other water molecules, as designated by OH−Y−.
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Lee, Huen, Jong-won Lee, Do Youn Kim, Jeasung Park, Yu-Taek Seo, Huang Zeng, Igor L. Moudrakovski, Christopher I. Ratcliffe, and John A. Ripmeester. "Tuning clathrate hydrates for hydrogen storage." In Materials for Sustainable Energy, 285–88. Co-Published with Macmillan Publishers Ltd, UK, 2010. http://dx.doi.org/10.1142/9789814317665_0042.
Full textConference papers on the topic "Hydrogen clathrate hydrate"
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Meindinyo, Remi-Erempagamo T., and Thor Martin Svartås. "Intermolecular Forces in Clathrate Hydrate Related Processes." In ASME 2015 34th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/omae2015-41774.
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The thermodynamics and kinetics of clathrate hydrate formation processes are topics of high scientific interest, especially in the petroleum industry. Researchers have made efforts at understanding the underlying processes that explicate the macroscopic observations from experiments and other research methods of gas hydrate formation. To achieve this, they have employed theories founded upon force related intermolecular interactions. Some of the theories and concepts employed include hydrogen bonding, the Leonard Jones force principle, and steric interactions. This paper gives a brief review of how these intermolecular interaction principles have been understood, and used as tools, in explaining the inaccessible microscopic processes, that characterize clathrate hydrate formation. It touches upon nucleation, growth, and inhibition processes.
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Nomura, Shinfuku, Andi Erwin Eka Putra, Hiromichi Toyota, Shinobu Mukasa, and Hiroshi Yamashita. "Fuel Gas Production by Plasma in a Microwave Oven at Atmospheric Pressure." In ASME/JSME 2011 8th Thermal Engineering Joint Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/ajtec2011-44365.
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The purpose of this research is to develop a process to use plasma decomposition of hydrocarbon liquids or clathrate hydrates in a microwave oven to produce fuel gas while simultaneously solidifying the carbon and synthesizing it into useful carbonized materials, such as CNTs or activated charcoal. Hydrogen gas with a purity of 60% to 80% can be extracted using a conventional microwave oven. This means that the energy efficiency of hydrogen production using this method is estimated to be approximately 50% of that by electrolysis of alkaline water and approximately 1% of that by the natural gas steam reforming method. However, this process has the added benefit of producing solid carbon at the same time. This method can be applied to a wide variety of waste liquids, or hydrate. Surplus electrical energy could be used to process waste liquids from homes and factories, and the resulting hydrogen energy could be stored and used.
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Aregbe, Azeez Gbenga, and Ayoola Idris Fadeyi. "A Comprehensive Review on CO2/N2 Mixture Injection for Methane Gas Recovery in Hydrate Reservoirs." In SPE Nigeria Annual International Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/207092-ms.
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Abstract Clathrate hydrates are non-stoichiometric compounds of water and gas molecules coexisting at relatively low temperatures and high pressures. The gas molecules are trapped in cage-like structures of the water molecules by hydrogen bonds. There are several hydrate deposits in permafrost and oceanic sediments with an enormous amount of energy. The energy content of methane in hydrate reservoirs is considered to be up to 50 times that of conventional petroleum resources, with about 2,500 to 20,000 trillion m3 of methane gas. More than 220 hydrate deposits in permafrost and oceanic sediments have been identified to date. The exploration and production of these deposits to recover the trapped methane gas could overcome the world energy challenges and create a sustainable energy future. Furthermore, global warming is a major issue facing the world at large and it is caused by greenhouse gas emissions such as carbon dioxide. As a result, researchers and organizations have proposed various methods of reducing the emission of carbon dioxide gas. One of the proposed methods is the geological storage of carbon dioxide in depleted oil and gas reservoirs, oceanic sediments, deep saline aquifers, and depleted hydrate deposits. Studies have shown that there is the possibility of methane gas production and carbon dioxide storage in hydrate reservoirs using the injection of carbon dioxide and nitrogen gas mixture. However, the conventional hydrocarbon production methods cannot be used for the hydrate reservoirs due to the nature of these reservoirs. In addition, thermal stimulation and depressurization are not effective methods for methane gas production and carbon sequestration in hydrate-bearing sediments. Therefore, the gas replacement method for methane production and carbon dioxide storage in clathrate hydrate is investigated in this paper. The research studies (experiments, modeling/simulation, and field tests) on CO2/N2 gas mixture injection for the optimization of methane gas recovery in hydrate reservoirs are reviewed. It was discovered that the injection of the gas mixture enhanced the recovery process by replacing methane gas in the small and large cages of the hydrate. Also, the presence of N2 molecules significantly increased fluid injectivity and methane recovery rate. In addition, a significant amount of free water was not released and the hydrate phase was stable during the replacement process. It is an effective method for permanent storage of carbon dioxide in the hydrate layer. However, further research studies on the effects of gas composition, particle size, and gas transport on the replacement process and swapping rate are required.
Reports on the topic "Hydrogen clathrate hydrate"
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John, Vijay T., Gary L. McPherson, Hank Ashbaugh, and Camille Y. Johnes. Molecular Design Basis for Hydrogen Storage in Clathrate Hydrates. Office of Scientific and Technical Information (OSTI), June 2013. http://dx.doi.org/10.2172/1086498.
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