• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 춘계학술대회
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• pp.609-614
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• 2005

Gas hydrates are ice-l ike sol id compounds that are composed of water and natural gas. All common gas hydrates belong to the three crystal structures that are composed of five polyhedral cavities formed by hydrogen bonded water molecules and stable in specific high pressure and low temperature conditions. Gas hydrates contain large amounts of organic carbon and widely occur in deep oceans and permafrost regions, and they may therefore represent a potential energy resource in the future. United States and Japan perform the national R&D programs for the commercial production of gas hydrates in 2010's. The study on gas hydrates are also important for exploration and development of natural gas in the regions where gas hydrates are accumulated and could be formed. Although their global abundance is debated, they play an important role in global climate change since methane is a 50 times more effect ive greenhouse gas than carbon dioxide. Natural gas hydrates also form a possible natural hazard if rapidly dissociated and can cause slides and slumps and in the marine environment associated tsunamis.

• 대한기계학회논문집B
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• 제27권2호
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• pp.251-258
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• 2003

Natural gas hydrates typically contain 85 wt.% water and 15 wt.% natural gas, and commonly belongs to cubic structure I and II. When referred to standard conditions, 1㎥ solid hydrates contain up to 172N㎥ 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. So, the tests were performed on the formation of natural gas hydrate is governed by the pressure, temperature, gas composition etc. The results show that the formation pressure of structure II is lower about 65% and the solubility is higher about 3 times than that of structure I.

• Journal of Mechanical Science and Technology
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• 제18권4호
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• pp.699-708
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• 2004

Natural gas hydrate typically contains 85 wt.% water and 15 wt.% natural gas, and commonly belongs to cubic structure I and II. When referred to standard conditions, 1 ㎤ solid hydrate contains up to 200㎥ of natural gas depending on pressure and temperature. Such the large volume of natural gas hydrate can be utilized to store and transport a large quantity of natural gas in a stable condition. In the present investigation, experiments were carried out for the formation of natural gas hydrate governed by pressure, temperature, gas compositions, etc. The results show that the equilibrium pressure of structure II is approximately 65% lower and the solubility is approximately 3 times higher than structure I. It is also found that for the sub-cooling of structure I and II of more than 9 and 11 K respectively, the hydrates are rapidly being formed. It is noted that utilizing nozzles for spraying water in the form of droplets into the natural gas dramatically reduces the hydrate formation time and increases its solubility at the same time.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 춘계학술대회
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• pp.652-655
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• 2005

Considering the fact that more than $97\%$ of fossil energy resources such as oil and natural gas needed in Korea rely on import, primary concern of the national economy is to secure future energy sources. Gas hydrates. which is non-conventional types of natural gas, distribute worldwide, especially in marine and permafrost Gas hydrates draw great attention recently as a new clean energy resources substituting conventional oil gas due to its presumed huge amount of volume reaching 10 trillion tons of gas and environmentally friendly characteristics. Results of preliminary survey by Korea Gas Corporation (KOGAS) and Korea Institute of Geoscience and Mineral Resources (KIGAM) showed that gas hydrates can be present in deep sea over 1,000m water depth in the East Sea. Gas hydrates can contribute to the rapidly increasing consumption of natural gas in Korea and achieve the self-support target by 2010 with $30\%$ of total natural gas demand. This study presents the potentialities and development prospects of gas hydrate as a future energy source.

• 한국자원공학회지
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• 제55권6호
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• pp.670-687
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• 2018

본 논문에서는 미래 에너지로서 가스 하이드레이트를 이해하기 위해, 가스 하이드레이트의 구조, 물리/화학적 특성, 생성 기원과 세계 분포, 매장량과 생산기법, 하이드레이트의 지구환경적 영향에 대해 논의하였다. 하이드레이트의 구조에 대한 명확한 이해는 자연계에 매장된 하이드레이트의 특성 분석, 분포와 매장량 산출에 필수적일 것으로 판단된다. 안정적인 에너지 회수를 위해 고려해야 할 하이드레이트의 물리/화학적 특성으로는 하이드레이트의 상평형, 해리 엔탈피, 열전도도, 비열, 열확산도, 유체투과율 등이 있다. 하이드레이트의 물리/화학적 특성을 고려하여 개발된 생산기법으로는 감압법, 열자극법, 억제제 주입법, 맞교환기법이 있으며, 감압법이 현재까지 해상 및 육상 하이드레이트에 대해 모두 시험생산에 적용된 유일한 기법이다. 또한, 하이드레이트의 해리에 따른 온실가스 배출에 의한 지구환경적 영향의 가능성에 대해서도 고찰하였다.

• 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.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집B
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• pp.241-246
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• 2000

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

• Ocean and Polar Research
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• 제23권1호
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• pp.51-62
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• 2001

The Arctic consists of numerous sedimentary basins containing voluminous natural resources and two of the world's major oil and gas producing areas. The western Siberia Basin in the Arctic region has the largest petroliferous province with an area of 800 ${\times}$ 1,200 km and produces more than 60% of total Russian oil production. The North Slope of Alaska produces about 20% of the U.S. output, i.e., 11% of the total U.S. consumption. Being small compared to those regions, the Canadian Northwest Territories and the Pechora Basin in Russia produce only fair amount of oil and natural gas. There are also many promising areas in the northern continental shelf of Russia. In addition to Russia, Svalbard and Greenland have been investigated for oil and gas. Gas hydrates are widespread in both permafrost regions and arctic continental shelf areas. The reserves of gas hydrates in the Arctic Ocean are about 20${\sim}$32% of total estimated amounts of gas hydrates in the world ocean. Mineral mining is well developed, especially in Russia. The major centers are located around the Kuznetsk Basin and Noril'sk. They are major suppliers of gold, tin, nickel, copper, platinum, cobalt, iron ore, coal as well as apatite. There are also some minings of lead-zinc in Alaska and Arctic Canada.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.419-423
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• 2006

Basic studies on natural gas hydrates in the East Sea were been carried out by the Korea Institute of Geoscience and Mineral Resources (KIGAM) from 2000 to 2004 involving 2D multichannel seismic lines and piston coring. 27 piston cores recovered from the deed-water Ulleung Basin of the East Sea were analyzed in this study. In piston cores cracks generally developed parallel to bedding suggest significant gas content. The core analyses showed high total organic carbon (TOC) content, sedimentation rate and heat flow of sediments. The cores recovered from the southern study area show also high residual hydrocarbon gas concentrations for the formation of natural gas hydrates. This study indicates that there is the potential for the generation of biogenic gas and the formation of natural gas hydrates in the near seafloor sediments of the study area.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2989-2994
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• 2007

Gas hydrates are ice-like crystalline compounds that form under low temperature and elevated pressure conditions. Although hydrate formation can pose serious flow-assurance problems in the gas pipelines or facilities, gas hydrates present a novel means for natural gas storage and transportation with potential applications in a wide variety of areas. An important property of hydrates that makes them attractive for use in gas storage and transportation is their very high gas-to-solid ratio. In addition to the high gas content, gas hydrates are remarkably stable. The main barrier to development of gas hydrate technology is the lack of an effective method to mass produce gas hydrate in solid form. The first objective of this study is investigating the characteristics of gas hydrate formation related to several factors such as pressure, temperature, water-to-storage volume ratio, concentration of SDS, heat transfer and whether stirred or not respectively. And the second objective is clarifying the relation between the formation efficiency and each factor in order to find the proper way or direction to improve the formation performance.