• Title, Summary, Keyword: gas hydrate

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Formation characteristics of gas hydrate in sediments (퇴적층에서의 가스 하이드레이트 생성 특성)

  • Lee, Jae-Hyoung;Lee, Won-Suk;Kim, Se-Joon;Kim, Hyun-Tae;Huh, Dae-Gi
    • 한국신재생에너지학회:학술대회논문집
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    • pp.630-633
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    • 2005
  • Some gases can be formed into hydrate by physical combination with water under appropriate temperature and pressure condition. Besides them, it was found that the pore size of the sediments can affect the formation and dissociation of hydrate. In this study, formation temperatures of carbon dioxide and methane hydrate have been measured using isobaric method to investigate the effects of flow rates of gases on formation condition of hydrate in porous rock samples. The flow rates of gases were controlled using a mass flow controller. To minimize Memory effect, system temperature increased for the dissociation of gas hydrates and re-established the initial saturation. The results show that the formation temperature of hydrate decreases with increasing the injection flow rate of gas. This indicates that the velocity of gas in porous media may act as kinds of inhibitor for the formation of hydrate.

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A Comparative Study on the Effect of THF and Oxidized Carbon Nanotubes for Methane Hydrate Formation (메탄 하이드레이트 생성을 위한 THF와 산화 탄소나노튜브의 영향에 대한 비교 연구)

  • Park, Sung-Seek;An, Eoung-Jin;Kim, Nam-Jin
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.23 no.12
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    • pp.769-775
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    • 2011
  • Methane hydrate is formed by physical binding between water molecules and methane gas, which is captured in the cavities of water molecules under the specific temperature and pressure. $1m^3$ hydrate of pure methane can be decomposed to the methane gas of $172m^3$ and water of $0.8m^3$ at standard condition. Therefore, there are a lot of practical applications such as separation processes, natural gas storage transportation and carbon dioxide sequestration. For the industrial utilization of hydrate, it is very important to rapidly manufacture hydrate. So in this study, hydrate formation was experimented by adding THF and oxidized carbon nanotubes in distilled water, respectively. The results show that when the oxidized carbon nanofluids of 0.03 wt% was, the amount of gas consumed during the formation of methane hydrate was higher than that in the THF aqueous solution. Also, the oxidized carbon nanofluids decreased the hydrate formation time to a greater extent than the THF aqueous solution at the same subcooling temperature.

Kirchhoff prestack depth migration for gas hydrate seismic data set (가스 하이드레이트 자료에 대한 중합전 키르히호프 심도 구조보정)

  • Hien, Doan Huy;Jang, Seong-Hyung;Kim, Young-Wan;Suh, Sang-Yong
    • 한국신재생에너지학회:학술대회논문집
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    • pp.493-496
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    • 2007
  • Korean Institute of Geosciences and Mineral Resources (KIGAM) has studied on gas hydrate in the Ulleung Basin, East sea of Korea since 1997. Most of all, a evidence for existence of gas hydrate, possible new energy resources, in seismic reflection data is bottom simulating reflection (BSR) which parallel to the sea bottom. Here we conducted the conventional data processing for gas hydrate data and Kirchhoff prestack depth migration. Kirchhoff migration is widely used for pre- and post-stack migration might be helpful to better image as well as to get the geological information. The processed stack image by GEOBIT showed some geological structures such as faults and shallow gas hydrate seeping area indicated by strong BSR. The BSR in the stack image showed at TWT 3.07s between shot gather No 3940 to No 4120. The estimated gas seeping area occurred at the shot point No 4187 to No 4203 and it seems to have some minor faults at shot point No 3735, 3791, 3947 and 4120. According to the result of depth migration, the BSR showed as 2.3km below the sea bottom.

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A Comparative Analysis on characteristics and Manufacture of Methane/Natural Gas Hydrates (메탄/천연가스 하이드레이트의 제조 및 특성 비교 분석)

  • Lee Young-Chul;Cho Byoung-Hak;Baek Young-Soon
    • Journal of the Korean Institute of Gas
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    • v.7 no.3
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    • pp.32-43
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    • 2003
  • As this paper is observed the phase equilibrium diagram of mono- (methane) and multi-component(natural gas) hydrates, and the hydrate growth behavior is analysed and compared by the experiments during the reaction. The difference of mono and multi-component hydrates is an induction delay time and a plateau region. And the concentration of component of gases is changed during the reaction in multi-component hydrates and the concentration of components is changed during the decomposition of hydrate according to each decomposing rates of gases. At 6 MPa, 276.65 K and 600 rpm, the induction delay time of multi-component hydrate formation is observed shorter than that of mono-component hydrate formation because the hydrate nuclei of gases except methane form faster than those of methane. And the plateau region of mono-component hydrate is observed distinctly at 0.055 mole of $CH_4$/mole of water and that of multi-component hydrate is observed at 0.04 mole of $CH_4$/mole of water.

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Electrical Resistivity Monitoring of Gas Hydrate Formation (가스하이드레이트 형성 과정의 비저항 모니터링)

  • Lee, J.Y.;Lee, J.H.;Lee, D.S.;Lee, W.S.;Kim, S.J.;Huh, D.G.;Kim, H.T.
    • 한국신재생에너지학회:학술대회논문집
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    • pp.186-187
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    • 2008
  • Electrical resistivity in hydrate-bearing sediments is sensitive to porosity, gas hydrate saturation, gas content, pore fluid composition, and temperature, so electrical measurements such as well logs and electromagnetic surveys have been used to explore gas hydrate-bearing formation. The high pressure tomography cell is designed considering the effect of electrode configuration and electrical shielding on tomography measurements and the safety. The evolution of electrical conductivity during $CO_2$ hydrate formation and dissociation reflects the combined effects of concurrent changes that include ionization of dissolved $CO_2$, temperature-dependent ionic mobility, changes in the degree of saturation, ion exclusion, surface conduction, and porosity changes. Measurements during hydrate formation and dissociation require careful analysis to properly interpret signatures, in particular when out-of plane conductivity anomalies prevail.

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Sound Velocity Property of Sediment Containing Gas Hydrate in the Ulleung Basin, East Sea (동해 울릉분지 가스하이드레이트 함유 퇴적물의 음파전달속도 특성)

  • Kim, Gil-Young;Yoo, Dong-Geun;Ryu, Byong-Jae
    • The Journal of the Acoustical Society of Korea
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    • v.28 no.5
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    • pp.424-431
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    • 2009
  • This study investigates the difference of sound velocity (compressional wave velocity) between gas hydrate-bearing sediments and nongas hydrate-bearing sediments in the Ulleung Basin, East Sea. We use a dataset measured from one site in the central part of the Ulleung Basin. Sound velocity for gas hydrate-bearing sediment shows the range from 1600 m/s to 2200 m/s. However, the value for nongas hydrate-bearing sediment is mostly around 1500 m/s, being less than 1400 m/s below 140 m subbottom depth. This trend is probably due to the presence of free gas below BSR (Bottom Simulating Reflector). Gas hydrate-bearing sediments show high value (maximum 150 Ohm-m) of resistivity. The physical properties between gas hydrate-bearing sediment and nongas hydrate-bearing sediment are characterized by the different patterns due to the presence of gas hydrate in comparison with those of marine unconsolidated sediments. Therefore, in order to investigate acoustic and physical properties for gas hydrate-bearing sediments, the study for the occurrence type and the amount of gas hydrates should be conducted simultaneously.

An Experimental Study on the Heat Transfer Characteristics to Enhance the Artificial Hydrate Formation Performance (전열특성을 이용한 가스하이드레이트 인공제조 성능향상에 대한 실험적 연구)

  • Shin, Chang-Hoon;Park, Seoung-Su;Kwon, Ok-Bae;Shin, Kwang-Sik;Choi, Yang-Mi;Lee, Jeong-Hwan
    • 한국신재생에너지학회:학술대회논문집
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    • pp.515-518
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    • 2007
  • Gas hydrates are ice-like crystalline compounds that form under low temperature and elevated pressure conditions. Recently, 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-sol id 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 mass production method of gas hydrate in solid form. In this study, some performance comparison among several cases classified by different volume sizes of solution were carried to identify the characteristics due to the volume increment. And it is found that one of the main reasons disturbing hydrate formation is related to the lack of cooling heat transfer due to the volume increase of the solution. So, three kinds of heat transfer plates which have different shapes and cross sectional areas were made and tested for the performance comparison following to the shape and area of each plate. Finally it is clarified that the heat transfer is one of the major factors effecting hydrate formation performance and the installation of heat transfer plate can enhance the formation performance especially not in terms of the quantity but the speed.

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A Study on the Gas Hydrate Productivity on the Sediment Properties (퇴적층 물성이 가스하이드레이트 생산성에 미치는 영향 연구)

  • Park, Seoung-Soo;Ju, Woo-Sung;Han, Jeong-Min;Lee, Kye-Jung;Lee, Jeong-Hwan
    • 한국신재생에너지학회:학술대회논문집
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    • pp.192-195
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    • 2008
  • Conventional gas deposits consist of pressurized gas held in porous and permeable reservoir rocks and its recovery takes place where the natural pressure of the gas reservoir forces gas to the surface. But gas hydrate is a crystalline solid, its prospects require reservoir rock properties approprate porosity, permeability with mapping of temperature and pressure conditions to define the hydrate stability zone. In this study, we have carried out to investigate the dissociation characteristics of methane hydrates and the productivities of dissociated gas and water with depressurization scheme. Also, it has been conducted the flowing behavior of the dissociated gas and water in porous rock and the efficiency of the production.

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Study on Methane Hydrate Formation in Seawater and Pure Water (해수와 순수물에서 메탄 하이드레이트 생성에 대한 연구)

  • Park, Sung-Seek;Kim, Nam-Jin
    • Journal of the Korean Solar Energy Society
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    • v.29 no.4
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    • pp.34-40
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    • 2009
  • $1m^3$ hydrate of pure methane can be decomposed to the maximum of $216m^3$ methane at standard condition. If these characteristics of hydrate are reversely utilized, natural gas is fixed into water in the form of hydrate solid. Therefore, the hydrate is considered to be a great way to transport and store natural gas in large quantity. Especially the transportation cost is known to be 18-24% less than the liquefied transportation. In the present investigation, experiments and theoretical calculation carried out for the formation of methane hydrate in NaCl 3.5wt% solution. The results show that the equilibrium pressure in seawater is more higher than that in pure water, and methane hydrate could be formed rapidly during pressurization if the subcooling is maintained at 9K or above in seawater and 8K or above in pure water, respectively. Also, amount of consumed gas volume in pure water is more higher that in seawater at the same experimental conditions. Therefore, it is found that NaCl acts as a inhibitor.

A Experimental Study of the Kinetic Characteristics of Methane Hydrate (메탄 하이드레이트 동적특성에 대한 실험적 연구)

  • Kim, Nam-Jin;Chun, Won-Gee
    • Journal of the Korean Solar Energy Society
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    • v.26 no.2
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    • pp.19-25
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    • 2006
  • Methane hydrate, non-polluting new energy resource, satisfies requirement and considered as a precious resource that can prevent the global warming. Fortunately, there are abundant resources of methane hydrate distribute in the earth widely. Therefore, developing the techniques that can utilize these gases effectively is highly desired. The work in this paper here is to develop a skill which can transport and store methane hydrate. As a first step, the equilibrium experiment was carried out by increasing temperatures in the cell at fixed pressures. The influence of gas consumption rates under variable degree of subcooling, stirring and water injection has been investigated formation to clarify kinetic characteristics of the hydrate. The results of present investigation showed that the enhancements of the hydrate formation in terms of the gas/water ratio are closely related to operational pressure, temperature, degrees of subcooling, and water injection.