(73l) Effect of Porous Media on the CO2 Hydrate Formation

The use of fossil fuels causes an increase in greenhouse gases, especially CO₂, in the atmosphere and is supposed to be a major factor on a global climate change. Many researches have tried to effectively reduce or to capture the major global warming gases. Especially, the hydrate formation mechanisms were intensively investigated for CO₂sequestration and storage process applications.

Gas hydrates are nonstoichiometric solid compounds of a polyhedral structure consisted of water molecules and interstitially encaging gas component molecules. The gas hydrates have a great potential to store and capture the vast amount of gas within them.

Higher solubility of hydrate forming guest in water and larger contact area between the hydrate formers and water is highly important. The contact area between the guest gas and water, which is the most critical factor for field operation, is dependent on the subcooling (ΔT) and driving force (ΔP) in the hydrate formation system. In recent years, researchers have suggested usage of certain additives to promote faster gas hydrate formation and increased surface area to volume of the fuel gas in hydrate forming systems. It has been shown that the gas hydrate formation could be faster in porous media and thus could be considered as kinetic promoter. The effect of different types of porous media, such as clays, sediment, activated carbon, carbon nanotube and silica gel, on hydrate formation are significant depending on the specific surface area, pore volume and pore size distribution.

Therefore, in this study, the effect of natural clay (montmorillonite and kaolinite) addition on the CO₂ separation and capture from fuel gas using the hydrate based gas separation process was evaluated. The CO₂ hydrate formation kinetics was investigated in the presence of porous media at constant temperature and pressure.