• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.549-552
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• 2009

Methane hydrate is crystalline ice-like compounds which formed methane gas enters within water molecules composed cavity at specially temperature and pressure condition, and water molecule and each other from physically-bond. $1m^3$ hydrate of pure methane can be decomposed to the maximum of $172m^3$ 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. However, when methane hydrate is formed artificially, the amount of consumed gas is relatively low due to a slow reaction rate between water and methane gas. In this study, for the better hydrate reaction rate, there is make nano fluid using ultrasonic dispersion of carbon nano tube. and then, Experiment with hydrate formation by nano fluid and methane gas reaction. The results show that when the carbon nano tubes of 0.004 wt% was added to pure water, the amount of consumed gas was about 300% higher than that in pure water and the hydrate formation time decreased.

• Korean Chemical Engineering Research
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• v.50 no.4
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• pp.690-695
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• 2012

Gas hydrate is an inclusion compound consisting of water and low molecular weight gases, which are incorporated into the lattice structure of water. Owing to its promising aspect to application technologies, gas hydrate has been widely studied recently, especially $CO_2$ hydrate for the CCS (Carbon Capture and Storage) issue. The key point of $CO_2$ hydrate technology for the CCS is how to produce gas hydrate in an efficient and economic way. In this study, we have tried to study the characteristic of gas hydrate formation using micro-sized ice through an ultrasonic nozzle which generate 2.4 MHz frequency wave. $CO_2$ as a carrier gas brings micro-sized mist into low-temperature reactor, where the mist and carrier gas forms $CO_2$ hydrate under $-55^{\circ}C$ and atmospheric pressure condition and some part of the mist also remains unreacted micro-sized ice. Formed gas hydrate was average 10.7 of diameter at average. The starting ice particle was set to constant pressure to form $CO_2$ hydrate and the consumed amount of $CO_2$ gas was simultaneously measured to calculate the conversion of ice into gas hydrate. Results showed that the gas hydrate formation was highly suitable because of its extremely high gas-solid contact area, and the formation rate was also very high. Self-preservation effect of $CO_2$ hydrate was confirmed by the measurement of $CO_2$ hydrate powder at normal and at pressed state, which resulted that this kind of gas storage and transport could be feasible using $CO_2$ hydrate formation.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.663-666
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• 2005

Gas hydrates are ice-like compounds that form at the low temperature and high pressure conditions common in shallow marine sediments at water depths greater than 300-500 m when concentrations of methane and other hydrocarbon gases exceed saturation. Estimates of the total mass of methane carbon that resides in this reservoir vary widely. While there is general agreement that gas hydrate is a significant component of the global near-surface carbon budget, there is considerable controversy about whether it has the potential to be a major source of fossil fuel in the future and whether periods of global climate change in the past can be attributed to destabilization of this reservoir. Also essentially unknown is the interaction between gas hydrate and the subsurface biosphere. ODP Leg 204 was designed to address these questions by determining the distribution, amount and rate of formation of gas hydrate within an accretionary ridge and adjacent basin and the sources of gas for forming hydrate. Additional objectives included identification of geologic proxies for past gas hydrate occurrence and calibration of remote sensing techniques to quantify the in situ amount of gas hydrate that can be used to improve estimates where no boreholes exist. Leg 204 also provided an opportunity to test several new techniques for sampling, preserving and measuring gas hydrates. During ODP Leg 204, nine sites were drilled and cored on southern Hydrate Ridge, a topographic high in the accretionary complex of the Cascadia subduction zone, located approximately 80km west of Newport, Oregon. Previous studies of southern Hydrate Ridge had documented the presence of seafloor gas vents, outcrops of massive gas hydrate, and a pinnacle' of authigenic carbonate near the summit. Deep-towed sidescan data show an approximately $300\times500m$ area of relatively high acoustic backscatter that indicates the extent of seafloor venting. Elsewhere on southern Hydrate Ridge, the seafloor is covered with low reflectivity sediment, but the presence of a regional bottom-simulating seismic reflection (BSR) suggests that gas hydrate is widespread. The sites that were drilled and cored during ODP Leg 204 can be grouped into three end-member environments basedon the seismic data. Sites 1244 through 1247 characterize the flanks of southern Hydrate Ridge. Sites 1248-1250 characterize the summit in the region of active seafloor venting. Sites 1251 and 1252 characterize the slope basin east of Hydrate Ridge, which is a region of rapid sedimentation, in contrast to the erosional environment of Hydrate Ridge. Site 1252 was located on the flank of a secondary anticline and is the only site where no BSR is observed.

• New & Renewable Energy
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• v.2 no.2 s.6
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• pp.94-101
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• 2006

[ $1m^3$ ] solid hydrate contains up to $200m^3$ of natural gas, depending on pressure and temperature. Such large volume of natural gas hydrate can be utilized to store and transport large quantity of natural gas in a stable condition. So, in the present investigation, experiments carried out for the formation of natural gas hydrate governed by pressure, temperature, and gas compositions, etc.. The results show that the equilibrium pressure of structure II natural gas hydrate) is approximately 65% lower and the solubility is approximately three times higher than structure I methane hydrate). Also, the subcooling conditions of the structure I and II must be above 9K and 11K in order to form hydrate rapidly regardless of gas components, but the pressure increase is more advantageous than the temperature decrease in order to increase the gas consumption. And 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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• 2006.06a
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• pp.399-402
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• 2006

[ $1m^3$ ] solid hydrate contains up to $200m^3$ of natural gas, depending on pressure and temperature. Such large volume of natural gas hydrate can be utilized to store and transport large quantity of natural gas in a stable condition. So, in the present investigation, experiments carried out for the formation of natural gas hydrate governed by pressure, temperature, and gas compositions, etc.. The results show that the equilibrium pressure of structure II natural gas hydrate (is approximately 65% lower and the solubility is approximately three times higher than structure I methane hydrate). Also, the subcooling conditions of the structure I and II must be above 9K and 11K in order to form hydrate rapidly regardless of gas components, but the pressure increase is more advantageous than the temperature decrease in order to increase the gas consumption. And 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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• 2008.05a
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• pp.107-110
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• 2008

The price of natural gas import continues to rise, as well as its domestic consumption rate. This research examined the economic feasibility of domestically developing and producing gas hydrate to substitute imported natural gas. Today, the technology to commercially produce gas hydrate is still lacking; however, if the gas hydrate is able to be commercially produced domestically and replace imported natural gas, the annual economic benefit for the Republic of Korea would be 211 - 833 USD/ton. From the industry's point of view, gas hydrate is a high value investment since one can expect an annual profit of over 150USD/ton. The commercial value of gas hydrate development will increase as long as the natural gas market continues to expand and as the increase of natural gas consumption remains steady. With further development of technology, one can anticipate an even higher expected return on the investment.

• Journal of the Korean Solar Energy Society
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• v.30 no.5
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• pp.11-16
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• 2010

Methane hydrate is crystalline ice-like compounds which formed methane gas enters within water molecules composed cavity and each other from physically-bond at specially temperature and pressure condition. $1m^3$ of methane hydrate can be decomposed into the maximum of $216m^3$ of methane gas under standard condition. If these characteristics of hydrate are utilized in the opposite sense, natural gas can be fixed into water in the form of a hydrate solid. Therefore the use of hydrate is considered to be a great way to transport and store natural gas in large quantity. However, when methane hydrate is formed artificially, the amount of gas that is consumed is relatively low, due to the slow reaction rate between water and methane gas. Therefore for practical purposes in the application, the present investigation focuses on increasing the amount of gas consumed by adding chemically oxidized OMWCNTs to pure water. The results show that when 0.003 wt% of oxidation multi-walled carbon nanotubes was added to pure water, the amount of gas consumed was almost four times more than that of pure water indicating its effect in hydrate formation and the hydrate formation time decreased at alow subcooling temperature.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.1317-1321
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• 2009

Natural gas liquefaction plant and LNG carrier needs large capital investment. Therefore a lot of small or middle scale natural gas fields aren't developed due to poor profitability. If natural gas is made to gas hydrate instead of liquefaction, developing small-scale natural gas field can be profitable because building cost of gas hydrate plant and carrier are economical. Because the process of making gas hydrate consumes much energy, the gas hydrate formation process has to be optimized for energy consumption. In this study, gas hydrate formation process was investigated experimentally. Experimental apparatus consists of reactor, pressure regulator, chiller, and magnetic stirrer. 99.95% methane was used to make gas hydrate. Tests were conducted at variable pressure and temperature condition.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.705-708
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• 2009

For the Gas hydrate Research and Development in Korea, the prospect area I & II was surveyed and drilled during the first phase. At the result, we succeeded to discovering gas hydrate real sample at BSR reflection and vent structure. This expedition processing contributes to developing the offshore seismic survey technologies and data processing of Korea. But Korean gas hydrate test production research, in spite of activating test production at other countries, is such a limitation about technician, GH production technologies and E&P processing. First of all, there is no exist in Korea to application site for the their production research results. In this paper, we have studied the gas hydrate reservoir selection technics of the DOE & BPXA for the ANS test production. And this result will helpful to preparation of gas hydrate test production in Korea.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.531-533
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• 2007

We report and discuss molecular and isotopic properties of hydrate-bound gases from 55 samples and void gases from 494 samples collected during Ocean Drilling Program (ODP) Leg 204 at Hydrate Ridge offshore Oregon. Gas hydrates appear to crystallize in sediments from two end-member gas sources (deep allochthonous and in situ) as mixtures of different proportions. In an area of high gas flux at the Southern Summit of the ridge (Sites 1248-1250), shallow (0-40 meters below the seafloor (mbsf)) gas hydrates are composed of mainly allochthonous mixed microbial and thermogenic methane and a small portion of thermogenic C2+ gases, which migrated vertically and laterally from as deep as 2-2.5 km depths. In contrast, deep (50-105 mbsf) gas hydrates at the Southern Summit (Sites 1248 and 1250) and on the flanks of the ridge (Sites 1244-1247) crystallize mainly from microbial methane and ethane generated dominantly in situ. A small contribution of allochthonous gas may also be present at sites where geologic and tectonic settings favor vertical gas migration from greater depth (e.g., Site 1244).