• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 춘계학술대회
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• pp.647-650
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• 2005

Gas hydrates draw great at tent ion recently as a new clean energy resources substituting conventional oil and gas hydrate its presumed huge amount of volume reaching 10 trillion tons of gas and environmentally friendly characteristics. Gas hydrate can contribute to the rapidly increasing consumption of natural gas in Korea and achieve the self support target by 2010 which is $30\%$ of total natural gas demand. This paper shows the importance and benefit of Gas hydrate comparing with new & renewable energy in Korea

• Ocean and Polar Research
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• 제26권3호
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• pp.515-521
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• 2004

The processes of formation and dissociation of gas hydrates were investigated by monitoring pressure and temperature variations in a pressure cell in order to understand the kinetic behavior of gas hydrate and the controlling factors fur the phase transition of gas hydrate below freezing. Gas hydrates were made kom guest gases ($CH_4,\;CO_2$, and their mixed-gas) and fine ice powder. We found that formation and dissociation speeds of gas hydrates were not controlled by temperature and pressure conditions alone. The results of this study suggested that pressure levels at the formation of mixed-gas hydrate determine the transient equilibrium pressure itself.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.519-523
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• 2007

Gas(or methane) hydrates are solid solutions when water molecules are linked through hydrogen bonding and create host lattice cavities that can enclose a large variety of guest gas molecules. The natural gas hydrate crystal may exist at low temperature above the normal freezing point of water and high pressure greater than about 30 bars. A lot of quantities of natural gas hydrates exists in the earth and many production schemes are being studied. In the present investigation, depressurization method was considered to predict the production of gas and the simulation of the two phase flow - gas and water - in porous media is being carried out. The simulation show about the fluid flow in porous media have a variety of applications in industry. Results provide the appearance of gas and water production, the pressure profile, the saturation of gas/ water/ hydrates profiles and the location of the pressure front.

• 한국태양에너지학회 논문집
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• 제28권6호
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• pp.8-14
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• 2008

Methane hydrate is crystalline ice-like compounds which consist of methane gas of 99% and over, and the estimated amount of gas contained in hydrates is about 1 trillion carbon Ton. Therefore, they have the potential for being a significant source for natural gas, and 1$m^3$ solid hydrates contain up to 172N$m^3$ of methane gas, depending on the pressure and temperature of production. Such large volumes make natural gas hydrates can be used to store and transport natural gas. In this study, the tests were performed on the formation of methane hydrate by a nozzle. The result showed that utilizing nozzles dramatically reduces the time in hydrate formation, the pressure after the injection is decreased to be approximately 90% of experimental pressurethe, and gas consumption is higher about 3 times than that of subcooling test.

• 한국태양에너지학회 논문집
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• 제30권1호
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• pp.34-41
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• 2010

Gas hydrates are solid solutions when water molecules are linked through hydrogen bonding and create host lattice cavities that can enclose many kinds of guest(gas) molecules. There are plenty of methane(gas) hydrate in the earth and distributed widely at offshore and permafrost. Several schemes, to produce methane hydrates, have been studied. In this study, depressurization method has been utilized for the numerical model due to it's simplicity and effectiveness. IMPES method has been used for numerical analysis to get the saturation and velocity profile of each phase and pressure profile, velocity of dissociation front progress and the quantity of produced gas. The values calculated for the sample length of 10m, show that methane hydrates has been dissolved completely in approximately 223 minutes and the velocity of dissociation front progress is 3.95㎝ per minute. The volume ratio of the produced gas in the porous media is found to be about 50%. Analysing the saturation profile and the velocity profile from the numerical results, the permeability of each phase in porous media is considered to be the most important factor in the two phase flow propagation. Consequently, permeability strongly influences the productivity of gas in porous media for methane hydrates.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.585-589
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• 2007

Gas hydrate is a special kind of inclusion compound that can be formed by capturing gas molecules to water lattice in high pressure and low temperature conditions. When referred to standard conditions, $1m^3$ solid hydrates contain up to $172Nm^3$ of methane gas, depending on the pressure and temperature of production, Such large volumes make natural gas hydrates can be used to store and transport natural gas. In this study, three-phase equilibrium conditions for forming methane hydrate were theoretically obtained in aqueous single electrolyte solution containing 3wt% Nacl. The results show that Nacl acts as a inhibitor, but help gases such as ethan, propane, i-butane, and n-butane reduce the hydrate formation pressure at the same temperature.

• Korean Chemical Engineering Research
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• 제61권3호
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• pp.394-400
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• 2023

이 연구에서는 메탄 가스(CH₄)와 함께 사이클로프로필아민(cyclopropylamine, CPrA)과 사이클로펜틸아민(cyclopentylamine, CPeA)을 이용한 하이드레이트의 튜닝효과, 가스 저장량, 그리고 하이드레이트의 열팽창 거동에 대해 논의하였다. 메탄 가스의 저장량을 극대화시킬 수 있도록 하이드레이트 튜닝 효과를 하이드레이트에 투입된 객체 분자의 농도를 달리 함에 따라 알아보았다. (CPrA+CH₄) 하이드레이트의 경우, 0.5 mol% 정도의 농도에서 최대 튜닝효과가 발생하였으며, (CPeA+CH₄) 하이드레이트는 기존 연구와 유사한 1.0 mol% 정도의 농도에서 최대 튜닝 효과가 발생하였다. (CPrA + CH₄), (CPeA + CH₄) 하이드레이트 모두 구조 II 하이드레이트를 형성한다고 알려진(테트라하이드로퓨란 + CH₄), (사이클로펜탄 + CH₄) 하이드레이트보다 더 많은 가스량을 저장하는 것으로 밝혀졌다. 100, 150, 200, 250 K의 조건에서(CPrA + CH₄), (CPeA + CH₄) 하이드레이트의 분말 X-선 회절 분석을 통해 각 온도별 격자 크기를 알아내고 그 차이를 분석하여 열팽창 거동을 분석하였다. 이에 따라, 객체 분자의 크기 차이로 인해(CPeA + CH₄) 하이드레이트의 격자 상수가 더 큰 것으로 확인되었다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.151-151
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• 2011

Large amounts of natural gas, mainly methane, in the form of hydrates are stored on continental margins. When gas hydrates are dissociated by any environmental trigger, generation of excess pore pressure due to released free gas may cause sediment deformation and weakening. Hence, damage on offshore structures or submarine landslide can occur by gas hydrate dissociation. Therefore, geotechnical stability of gas hydrate bearing sediments is in need to be securely assessed. However, geotechnical characteristics of gas hydrates bearing sediments including small-strain elastic moduli have been poorly identified. Synthesizing gas hydrate in natural seabed sediment specimen, which is mainly composed of silty-to-clayey soils, has been hardly attempted due to their low permeability. Moreover, it has been known that hydrate loci in pore spaces and heterogeneity of hydrate growth in specimen scale play a critical role in determining physical properties of hydrate bearing sediments. In the presented study, we synthesized gas hydrate containing sediments in an instrumented oedometric cell. Geotechnical and geophysical properties of gas hydrate bearing sediments including compressibility, small-strain elastic moduli, elastic wave, and electrical resistivity are determined by wave-based techniques during loading and unloading processes. Significant changes in volume change, elastic wave, and electrical resistivity have been observed during formation and dissociation of gas hydrate. Experimental results and analyses reveal that geotechnical properties of gas hydrates bearing sediments are highly governed by hydrate saturation, effective stress, void ratio, and soil types as well as morphological feature of hydrate formation in sediments.

• Journal of Korean Society for Atmospheric Environment
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• 제23권E1호
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• pp.10-15
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• 2007

The gas hydrates are probably most sensitive to climate change since they are stable only under specific conditions of high pressure and low temperature. One of the main factors responsible for formation of gas hydrates is the saturation of the gases with water vapor. Quantitative phase equilibrium data and understanding of the roles of water component in the phase behavior of the heterogeneous water-hydrocarbon-hydrate mixture are of importance and of engineering value. In this study, the water content of ethylene gas in equilibrium with hydrate and water phases were analyzed by theoretical and experimental methods at temperatures between 274.15 up to 291.75 K and pressures between 593.99 to 8,443.18 kPa. The experimental and theoretical enhancement factors (EF) for the water content of ethylene gas and the fugacity coefficients of water and ethylene in gas phase were determined and compared with each other over the entire range of pressure carried out in this experiment. In order to get the theoretical enhancement factors, the modified Redlich-Kwong equation of state was used. The Peng-Robinson equations and modified Redlich-Kwong equations of state were used to get the fugacity coefficients for ethylene and water in the gas phase. The results predicted by both equations agree very well with the experimental values for the fugacity coefficients of the compressed ethylene gas containing small amount of water, whereas, those of water vapor do not in the ethylene rich gas at high temperature for hydrate formation locus.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 추계학술대회
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• pp.58-61
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• 2006

n-Pentane and n-hexane, previously regarded as non-hydrate formers, are found to form structure H hydrate in mixtures with 2,2-dimethylbutane. Even though they are thought to be too large to fit into the largest cage of the structure H hydrate, powder XRD and NMR measurements show that they form gas hydrates in mixtures with other sH hydrate former. These findings are of fundamental interest and also will impact the composition and location of natural gas hydrates and their potential as global energy resource and climate change materials.