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...

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...

Gas hydrates are ice-like deposits containing a mixture of water and gas; the most common gas is methane. Gas hydrates are stable under high pressures and relatively low temperatures and are found underneath the oceans and in permafrost regions. Estimates range from 500 to 10,000 giga tonnes of carbon (best current estimate 1600-2000 GtC) stored in ocean sediments and 400 GtC in Arctic permafro...

Gas hydrates attracted worldwide attention due to their potential as huge energy resource in the recent decades. Effective parameters which influence the formation of hydrates are high pressure, low temperature and water presence. HYSYS software is one of the major simulators which are widely used in the chemical and thermodynamic processes. This research was conducted to simulate gas hydrate f...

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 ...

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...

Synopsis Clathrate hydrates have been found to occur naturally, and have been extensively studied due to their important industrial applications, such as the storage of the CO2 from the atmosphere and control climate change. Thus, quantitative understanding of physical and chemical properties, as well as the factors that control the formation of CO2 hydrates, on both macroscopic and microscopic...

1 Calcium Silicate Hydrates in cementitious materials 1.1 Sustainability Challenge .... ..................... 1.2 Cement Chemistry Notation A Primer ............ 1.3 Hydration of Portland Cement ...................... 1.3.1 Initial and slow reaction periods . . . . . . . . . . . . . 1.3.2 Nucleation & Growth of C-S-H . . . . . . . . . . . . . 1.3.3 Open Questions in Cement Hydration . . . . . ....

Structural changes and preferential cage occupancies were examined for ethane hydrate and ethane-methane mixed gas hydrates with five compositions in a pressure range of 0.2 to 2.8 GPa at room temperature. X-ray diffractometry and Raman spectroscopy showed the following structural changes. The initial structure, structure I (sI), of ethane hydrate was retained up to 2.1 GPa without any structur...