Gas hydrates are a vast energy resource with global distribution in the permafrost and in the oceans. Even if conservative estimates are considered and only a small fraction is recoverable, the sheer size of the resource is so large that it demands evaluation as a potential energy source. In this review paper, we discuss the distribution of natural gas hydrate accumulations, the status of the p...

The kinetics of nucleation of one-component gas hydrates in aqueous solutions are analyzed. The size of the hydrate nucleus and the work for nucleus formation are determined as functions of the supersaturation Dm: Expressions for the stationary rate J of hydrate nucleation are derived. These expressions describe the JðDmÞ dependence for homogeneous nucleation and for heterogeneous nucleation at...

The combustion characteristics of both pure propane hydrates and the mixtures of hydrates and quartz sands were investigated by combustion experiments. The flame propagation, flame appearance, burning time and temperature in different hydrate layers were studied. For pure propane hydrate combustion, the initial flame falls in the “premixed” category. The flame propagates very rapidly, mainly as...

Gas hydrate blockage in pipelines during offshore production becomes a major problem with increasing water depth. In this work, a series of experiments on gas hydrate formation in a flow loop was performed with low flow rates of 0.33, 0.66, and 0.88 m/s; the effects of the initial subcooling, flow rate, pressure, and morphology were investigated for methane hydrate formation in the flow loop. T...

EXECUTIVE SUMMARY The UNEP Global Outlook on Methane Gas Hydrates seeks to provide policy makers, the general public and the media with a synthesis of aspects of natural, social and applied sciences that relate to this type of natural gas occurrence. With an emphasis on visual media, the Outlook is working to define global methane gas hydrate occurrences in their natural settings and examine th...

Clathrates are crystalline inclusion compounds formed by a physically stable reaction between host and guest molecules. Gas hydrate and hydroquinone (HQ) clathrate are one of the most studied and welldefined clathrate compounds. In this study, guest-free, CO2-loaded, CH4-loaded and CO2/CH4-loaded HQ clathrates were synthesized by gas-phase reaction and recrystallization. In addition, pure CO2 a...

Blockage of pipelines by formation and accumulation of clathrate hydrates of natural gases (also called gas hydrates) can compromise project safety and economics in oil and gas operations, particularly at high pressures and low temperatures such as those found in subsea or arctic environments. Cyclopentane (CyC5) hydrate has attracted interest as a model system for studying natural gas hydrates...

based on driving force for crystallization of one-component gas hydrate, in this report an expression for the supersaturation for crystallization of multicomponent gas hydrate is derived. expressions for the supersaturation are obtained in isothermal and isobaric regimes. the results obtained are applied to the crystallization of hydrates of mixtures of methane plus ethane and can apply to othe...