نتایج جستجو برای: apg gas hydrates

تعداد نتایج: 246976  

Masoud Aghajani Reza Razizadeh, Vahid Mohebbi,

The super-saturation condition has to be provided to form gas hydrates. Consequently, the prediction of the guest molecule fraction in the aqueous phase is crucial in the study of the gas hydrate kinetics. In the present work, several experiments were carried out in a semi-batch reactor in order to determine the mole fraction of methane and ethane during gas hydrates formation (growth stage...

2007
K. C. Hester E. T. Peltzer

Oceanic gas hydrates have been measured near the seafloor for the first time using a seagoing Raman spectrometer at Hydrate Ridge, Oregon, where extensive layers of hydrates have been found to occur near the seafloor. All of the hydrates analyzed were liberated from the upper meter of the sediment column near active gas venting sites in water depths of 770– 780 m. Hydrate properties, such as st...

2005
Do-Youn Kim Jong-won Lee Yu-Taek Seo John A. Ripmeester Huen Lee

Gas hydrates, or more generally clathrate hydrates, are a type of inclusion compound and take the form of nonstoichiometic solid crystalline materials formed from water and small guest molecules. Under sufficient pressure of the guest material and at specific temperatures, 3D hydrate structures are formed by the stacking of polyhedral cages of hydrogenbonded water molecules. Suitably sized gues...

2007
Christian Berndt Bedanta Goswami

The thickness of the free gas column below the base of the gas hydrate stability zone is a proxy for the pore pressure in the free gas bearing sediments underneath. In the study area the pore over-pressrues derived under this assumption range between 0 and 1430 kPa ± 30% which appear to be the typical maximum over-pressure that the gas hydrate sediments can withstand before hydro-fracturing occ...

Journal: :Energy Exploration & Exploitation 2000

2017
Václav Vinš Andreas Jäger Sebastian Hielscher Roland Span Jan Hrubý Cornelia Breitkopf

The temperature and pressure correlations for the volume of gas hydrates forming crystal structures sI and sII developed in previous study [Fluid Phase Equilib. 427 (2016) 268-281], focused on the modeling of pure gas hydrates relevant in CCS (carbon capture and storage), were revised and modified for the modeling of mixed hydrates in this study. A universal reference state at temperature of 27...

2007
J. S. Loveday R. J. Nelmes

Many simple gases that do not interact strongly with water form crystalline hydrates in which the gas molecules or atoms occupy ‘cages’ formed by a framework of water molecules. These clathrate hydrates are stabilised by hydrophobic gas-water interactions and are model systems for the study of these interactions. Many gas hydrates also occur in nature and their properties provide a basis for mo...

2011
Judith M. Schicks Erik Spangenberg Ronny Giese Bernd Steinhauer Jens Klump Manja Luzi

The presence of natural gas hydrates at all active and passive continental margins has been proven. Their global occurrence as well as the fact that huge amounts of methane and other lighter hydrocarbons are stored in natural gas hydrates has led to the idea of using hydrate bearing sediments as an energy resource. However, natural gas hydrates remain stable as long as they are in mechanical, t...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 2006
amir abbas izadpanah mohsen vafaie sefti farshad varaminian

the michelsen stability and multiphase flash calculation by direct minimization of gibbs free energy of the system at constant temperature and pressure, was used for systems containing gas hydrates. the solid hydrate phase was treated as a solid solution. the fugacities of all components of the hydrate phase were calculated as a function of compositions by the rearranged model of van der waals ...

2008
M. D. White

Scientific and technological innovations are needed to realize effective production of natural gas hydrates. Whereas global estimates of natural gas hydrate reservoirs are vast, accumulations vary greatly in nature and form. Suboceanic deposits vary from disperse concentrations residing at low saturations in the pore space of unconsolidated sediments with sand-sized particles to higher concentr...

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