• Title/Summary/Keyword: Gas Hydrate

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A Case Study of Test Production of Gas from Hydrate Bearing Sediments on Nankai Trough in Japan (일본 난카이 해구 가스하이드레이트 퇴적층으로부터의 가스 시험생산 사례분석)

  • Kim, A-Ram;Lee, Jong-Won;Kim, Hyung-Mok
    • Tunnel and Underground Space
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    • v.25 no.2
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    • pp.133-143
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    • 2015
  • Gas hydrate is a solid substance composed of natural gas constrained in water molecules under low temperature and high pressure conditions. The existence of hydrates has been reported to be world-widely distributed, mainly at permafrost and deep ocean floor. Test productions of small amount of natural gas from the on-shore permafrost have been accomplished in U.S.A and Canada, but, world-first and the only production case from off-shore hydrate bearing sediments was in Nankai trough, Japan. In this study, we introduce key technologies in gas production from hydrates by analyzing the Japanese off-shore gas production project in Nankai trough in terms of depressurization- induced dissociation so as to utilize planned domestic gas production test in Ulleung basin.

Investigation on Formation Behaviors of Synthesized Natural Gas Hydrates (합성 천연가스의 하이드레이트 형성 거동 연구)

  • Lee, Jong-Won;Lee, Ju-Dong
    • Korean Chemical Engineering Research
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    • v.50 no.5
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    • pp.890-893
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    • 2012
  • Gas hydrates are solid crystal structures formed by enclathration of gaseous guest species into 3-dimensional lattice structure of hydrogen-bonded water molecules. These compounds can be potentially used as an energy storage/transportation medium because they can hold a large amount of gas in a small volume of the solid phase. In addition, huge amount of natural gas, buried in seabeds or permafrost region in the form of the solid hydrate, is regarded as a future energy source. In this study, synthesized natural gas, whose composition is 90.0 mol% of methane, 7.0 mol% of ethane, and 3.0 mol% of propane, was used to identify formation behaviors of natural gas hydrates for the purpose of applying the gas hydrate to a storage/transportation medium of natural gas. According to the experimental results obtained by means of the solid-state NMR and high-resolution powder XRD methods, it is found that formed natural gas hydrates have crystal structure of the structure-II hydrate, and that methane occupies both small and large cages, while the others only occupy large ones. In addition, both the NMR spectroscopy and the gas chromatograph showed that there exists preferential occupation among the natural gas components during the hydrate formation. Compositional changes after the hydrate formation revealed that the preferential occupation is in order of propane, ethane, and methane (propane is the most preferential guest species when forming natural gas hydrates).

The Development Prospect for Gas Hydrate as an Energy Source (에너지원으로서의 가스 하이드레이트 개발 전망)

  • Baek Youngsoon;Lee Jeonghwan;Choi Yangmi;Park Seoungmin
    • 한국신재생에너지학회:학술대회논문집
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    • 2005.06a
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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.

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Gas Hydrate Phase Equilibria of $CO_2+H_2$ Mixture in Silica Gel Pores for the Development of Pre-combustion Capture (연소 전 이산화탄소 회수기술을 위한 실리카겔 공극 내에서의 이산화탄소+수소 혼합가스 하이드레이트의 상평형)

  • Kang, Seong-Pil;Jang, Won-Ho;Jo, Wan-Keun
    • Clean Technology
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    • v.15 no.4
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    • pp.258-264
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    • 2009
  • Thermodynamic measurements were performed to show the possibility of recovering $CO_2$ from fuel gas (the mixture of $CO_2$ and $H_2$) by forming gas hydrates with water where water was dispersed in the pores of silica gel particles having nominal 100 nm of pore diameter. The hydrate-phase equilibria for the ternary $CO_2+H_2$+water in pores were measured and $CO_2$ concentrations in vapor and hydrate phase were determined under the hydrate-vapor two phase region at constant 274.15 K. It was shown that the inhibition effect appeared due to silica gel pores, and the corresponding equilibrium dissociation pressures became higher than those of bulk water hydrates at a specific temperature. In addition, direct measurement of $CO_2$ content in the hydrate phase showed that the retrieved gas from the dissociation of hydrate contained more than 95 mol% of $CO_2$ when 42 mol% of $CO_2$ and balanced Hz mixture was applied. Compared with data obtained in case of bulk water hydrates, which showed just 83 mol% of $CO_2$ where 2-stage hydrate slurry reactor was intended to utilize this property, the hydrate formation in porous silica gel has enhanced the feasibility of $CO_2$ separation process. Hydrate formation as not for slurry but solid particle makes it possible to used fixed bed reactor, and can be a merit of well-understood technologies in the industrial field.

Methane hydrate : The state of the art of Production technologies and environmental issues (메탄 하이드레이트의 생산 기술 현황과 환경에 미치는 영향)

  • Chang Seung yong
    • The Korean Journal of Petroleum Geology
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    • v.7 no.1_2 s.8
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    • pp.13-18
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    • 1999
  • Methane hydrate is an ice-like solid material and it has a structure which water molecules enclose gas molecules. For low temperature and high pressure, hydrocarbon gas forms hydrate and due to this condition, it is existed in the arctic region or deep sea. Presently, the amount of methane hydrate is unpredictable, but it is assumed that the amount will be enormous. For this reason, it is expected that it will play a major role as natural gas resources in the future. However, the production technologies are stayed on the low level and the economical technology was not developed yet. Also, emission of natural gas from methane hydrate will cause global warming and thus it is considered as a critical environmental problem. In this paper, the state of the art of the production technologies and environmental effects of methane hydrate were summarized.

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Study on Characteristic of Self-preservation Effect of CO2 Hydrate according to Temperature, Particle Diameter and Shape (온도, 직경, 형태에 따른 CO2 하이드레이트의 자기보존효과 특성 연구)

  • Kim, Yeon-Soo;Kang, Seong-Pil;Park, So-Jin
    • Korean Chemical Engineering Research
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    • v.51 no.5
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    • pp.602-608
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    • 2013
  • Gas hydrate studies are attracting attention of many researchers as an innovative, economic and environmentally friendly technology when it is applied to $CO_2$ capture, transport, and storage. In this study, we investigated whether $CO_2$ hydrate shows the self-preservation effect or not, that is the key property for developing a novel $CO_2$ transport/storage method. Especially the degree of self-preservation effect for $CO_2$ hydrate was studied according to the particle size of $CO_2$ hydrate samples. We prepared three kinds of $CO_2$ hydrate samples varying their particle diameter as millimeter, micron and nano size and measured their change of weight at $-15{\sim}-30^{\circ}C$ under atmospheric pressure during 3 weeks. According to our experimental result, the lower temperature, larger particle size, and compact structure for higher density are the better conditions for obtaining self-preservation effect.

Study of Methane Storage through Structure Transition of Gas Hydrate (가스하이드레이트 구조 변형을 통한 메탄 저장에 관한 연구)

  • Lee, Ju-Dong;Lee, Man-Sig;Kim, Young-Seok
    • 한국신재생에너지학회:학술대회논문집
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    • 2006.11a
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    • pp.54-57
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    • 2006
  • Structure H formation experiments were conducted in a semi-batch stirred vessel using methane as the small guest substance and neohexane(NH), tert-butylmethylether(TBME) and methylcyclohexane(MCH) as the large molecule guest substance (LMGS). The results indicate that the rates of gas uptake and induction times are generally dependent on the magnitude of the driving force. When tert-butyl methyl ether is used as the LMGS rapid hydrate formation, much smaller induct ion time and rapid decomposition can be achieved. Liquid-liquid equilibrium (LLE) data for the above LMGS with water have been measured under atmospheric pressure at 275.5, 283.15K, and 298.15K. It was found that TBME is the most water soluble followed by NM and MCH. The solubility of water in the non-aqueous liquid was found to increase in the following order: MCH

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An Experimental Analysis of Hydrate Production using Multi-Well, Plate-Type Cell Apparatus (다중공 평판형 셀기기에서 하이드레이트 생산실험 분석연구)

  • Bae, Jaeyu;Sung, Wonmo;Kwon, Sunil
    • Korean Chemical Engineering Research
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    • v.45 no.3
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    • pp.304-309
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    • 2007
  • In this study, the "Multi Well Plate-type cell Apparatus" was designed and setup for performing the producing experiments of methane hydrate by depressurization, heat stimulating methods. In order to characterizing the producing mechanism of hydrate through porous materials, the experiments for various producing methods have been conducted with the aid of the apparatus which has high permeability. In the experimental result of depressurization method, the pressure is temporarily increased unlikely conventional gas reservoir due to the sourcing effect of hydrate dissociation in the pore. Meanwhile, the temperature is decreased because of the endothermic reaction while hydrate is dissociated. In the experimental results of heat stimulating method, the dissociation in depressurization method is more slowly processed than that in thermal method, and hence, its gas production is lower. In the case of production right after heating, hydrate is dissociated only near injecting point and the permeability becomes greater at that area only. It infers that the more gas is produced during relatively earlier producing period. Since then, the hydrate is more slowly dissociated than the case of production after heating and soaking. This time, the performances of pressure and production obtained by thermal method have been analyzed in order to investigate the effect of soaking time on gas recovery. As a result, the gas recoveries in the case of 2 min and 4 min soaking are higher than case in 6 min soaking. This is reason that hydrate is reformed due to the decrease of temperature. It is expected that the experimental results obtained in this work may be more clearly explained by utilizing the lower permeable porous system with the greater hydrate saturation.

Hydrate formation/dissociation mechansims in sediments and their implications to the exploration and the production (퇴적물 내의 하이드레이트 생성/해리 메커니즘과 탐사 및 개발생산에의 적용)

  • Lee, J.Y.
    • 한국신재생에너지학회:학술대회논문집
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    • 2008.05a
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    • pp.588-590
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    • 2008
  • The thermal signature of nucleation process is characterized by the induction time, the degree of supercooling, and the equilibrium temperature depression. The initiation of nucleation presents stochastic characteristics. The factors that affect nucleation are mechanical impact, ionic concentration, mineral surface characters, and pore size. Hydrate-bearing sediments behave mechanically like other cemented sediments. The data set has important implications for the calibration and interpretation of geophysical measurements and downhole logs collected in gas hydrate provinces, providing particular insight for the interpretation of P- and S-wave data and resistivity logs. In addition, laboratory formation history and ensuing pore-scale spatial distribution likely have a more pronounced effect on the macroscale mechanical properties of hydrate-bearing sediments

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An Experimental Study on Investigation of the Main Factors to Improve the Formation Performance of Gas Hydrate (가스하이드레이트 생성성능 향상을 위한 주요인자별 특성 규명에 관한 실험적 연구)

  • Lee, Jeong-Hwan
    • Journal of the Korean Institute of Gas
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    • v.13 no.3
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    • pp.15-21
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    • 2009
  • Gas hydrate is an ice-like crystalline compound that forms at low temperature and high pressure conditions. It consists of gas molecules surrounded by cages of water molecules. Although hydrate formation was initially found to pose serious flow-assurance problems in the gas pipelines or facilities, gas hydrates have much potential for application in a wide variety of areas, such as natural gas storage and transportation. Its very high gas-to-solid ratio and remarkably stable characteristics makes it an attractive candidate for such use. However, it needs to be researched further since it has a slow and complex formation process and a high production cost. In this study, formation experiments have been carried out to investigate the effects of pressure, temperature, water-to-storage volume ratio, SDS concentration, heat transfer and stirring. The results are presented to clarify the relationship between the formation process and each factor, which consequently will help find the most efficient production method.

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