• Title/Summary/Keyword: $CO_2$ hydrate

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Effects of Promoter on the Formation of Gas Hydrate from Blast Furnace Gas (철강공정 배기가스로부터 가스 하이드레이트 형성에 미치는 촉진제의 영향)

  • Kwak, Gye-Hoon;Sa, Jeong-Hoon;Kim, Si-Hwan;Lee, Bo Ram;Lee, Kun-Hong
    • Korean Chemical Engineering Research
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    • v.53 no.1
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    • pp.103-110
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    • 2015
  • In this work, the performance of various promoters was investigated used in $CO_2$ separation from the gases emitted from steel-making process using gas hydrate technology. The studied promoters are tetrahydrofuran (THF), propylene oxide and 1,4-dioxane, which are all expected to form a structure II hydrate, and the target gases include $CO_2/N_2$ mixed gases ($CO_2/N_2$ = 20/80 and 40/60) and Blast Furnace Gas (BFG). The phase equilibrium points were measured when each promoter was added with various concentrations. For fast acquisition of abundant data, the "continuous" Quartz crystal microbalance (QCM) method was employed. In addition, the crystal structure of each gas hydrate was analyzed by Powder X-ray diffraction (PXRD).

$CO_2$ Hydrate Phase Equilibria with Green Thermodynamic Hydrate Inhibitors (친환경적인 열역학적 저해제를 첨가한 $CO_2$ 하이드레이트 상평형 측정)

  • Sa, Jeong-Hoon;Lee, Bo Ram;Park, Da-Hye;Lee, Kun-Hong
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.11a
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    • pp.150.2-150.2
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    • 2010
  • 가스 하이드레이트는 낮은 온도와 높은 압력 조건에서 물 분자들이 수소 결합을 통해 형성하는 3차원의 격자구조에 저분자량의 기체 분자들이 포획되어 있는 결정성 화합물이다. 가스 하이드레이트는 형성 시 많은 양의 가스를 저장할 수 있는 특성을 가진다. 천연 가스를 심해저로 수송하는 수송관 내부에 가스 하이드레이트가 생성되면 막힘 현상이 일어나 비용과 시간 측면에서 막대한 손실이 일어날 수 있다. 따라서 이를 방지하기 위해 열역학적 상평형 조건을 변화시켜 가스 하이드레이트 형성을 방지할 수 있는 열역학적 저해제에 관한 연구의 필요성이 요구된다. 본 연구에서는 Glycine, Alanine 등의 열역학적 저해제를 5, 10, 15 wt% 등으로 첨가하여 $CO_2$ 하이드레이트의 상평형 조건에 미치는 영향을 측정하였고, 각 물질을 12.5, 22.0 mmol%로 첨가하여 물질에 따라 상평형에 미치는 영향을 비교하여 보았다. 또한 Alanine의 두 가지 광학 이성질체를 같은 농도로 첨가하여 각 물질에 따라 상평형에 미치는 영향을 비교하였다.

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Recent Research Trends on Separation of CO2 Emitted From Steelmaking Process using Gas Hydrate Technology (가스 하이드레이트 형성 원리를 이용한 철강공정 배기가스 중 CO2 분리기술에 대한 최근 연구 동향)

  • Lee, Bo Ram;Ryu, Jun-Hyung;Han, Kunwoo;Park, Da-Hye;Lee, Kun-Hong;Lee, In-Beum
    • Korean Chemical Engineering Research
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    • v.48 no.2
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    • pp.232-243
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    • 2010
  • Gas hydrates are crystalline solids composed of water and gas molecules. Water molecules are linked through hydrogen bonding and create cavities(host lattice) that can capture a large variety of guest molecules under appropriate conditions, generally high pressure and low temperature. Recently, many researchers try to apply gas hydrates to industrial processes to capture greenhouse gases due to the facts that the process is eco-friendly and target gas molecules can be preferentially captured. In this paper, we introduced recent studies on $CO_2$ and $CO_2-N_2$ mixture hydrates to evaluate the feasibility of industrial application of gas hydrate technology to $CO_2$ capture process. Specifically, we put emphasis on the technical feasibility of $CO_2$ separation in steel industry using gas hydrate formation principles.

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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    • 2008.10a
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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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Salinity Effect on the Equilibria and Kinetics of the Formation of CO2 and R-134a Gas Hydrates in Seawater

  • Johanna, Lianna;Kim, A Ram;Jeong, Guk;Lee, Jea-Keun;Lee, Tae Yun;Lim, Jun-Heok;Won, Yong Sun
    • Korean Journal of Materials Research
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    • v.26 no.7
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    • pp.382-387
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    • 2016
  • Gas hydrates are crystalline solids in which gas molecules (guests) are trapped in water cavities (hosts) that are composed of hydrogen-bonded water molecules. During the formation of gas hydrates in seawater, the equilibria and kinetics are then affected by salinity. In this study, the effects of salinity on the equilibria of $CO_2$ and R134-a gas hydrates has been investigated by tracing the changes of operating temperature and pressure. Increasing the salinity by 1.75% led to a drop in the equilibrium temperature of about $2^{\circ}C$ for $CO_2$ gas hydrate and $0.38^{\circ}C$ for R-134a gas hydrate at constant equilibrium pressure; in other words, there were rises in the equilibrium pressure of about 1 bar and 0.25 bar at constant equilibrium temperature, respectively. The kinetics of gas hydrate formation have also been investigated by time-resolved in-situ Raman spectroscopy; the results demonstrate that the increase of salinity delayed the formation of both $CO_2$ and R134-a gas hydrates. Therefore, various ions in seawater can play roles of inhibitors for gas hydrate formation in terms of both equilibrium and kinetics.

Technology Trend for Gas Hydrate Production Method by the Patent Analysis (특허 분석에 의한 가스 하이드레이트 제조 기술 동향)

  • Kang, Seong-Pil;Seo, Yu-Teak;Keum, Young-Sup;Ahn, Myung-Hee
    • Transactions of the Korean hydrogen and new energy society
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    • v.19 no.2
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    • pp.171-181
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    • 2008
  • There are several methods for the gas hydrate production such as spraying water with countercurrent gas flow, stirring water-gas mixture, and flowing water with micro-bubble, etc. These days it has been widely studied for the gas hydrate production method, having low energy consumption and high efficiency. In this paper, patents in the gas hydrate production method were gathered and analyzed. The search range was limited to the open patents of USA, European Union (EP), Japan (JP), and Korea (KR) from 1991 to 2007. Patents were gathered by using keywords searching and filtered by crucial criteria. The trends of the patents were analyzed by the years, countries, companies, and technologies.

Comparison on the Energy Consumption of the Vacuum Evaporation and Hydrated-Based Technologies for Concentrating Dissolved Ions (용존 이온 농축을 위한 진공 증발 기술과 하이드레이트 기반 기술의 소모 에너지 비교)

  • Han, Kunwoo;Rhee, Chang Houn;Ahn, Chi Kyu;Lee, Man Su
    • Korean Chemical Engineering Research
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    • v.57 no.3
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    • pp.378-386
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    • 2019
  • In the present paper we report the calculation results of operation energy consumption for dissolved ions concentration technologies using vacuum evaporation (VE) and hydrate formation. Calculations were conducted assuming the tenfold concentration of saline water (0.35 wt% NaCl solution) of 1 mol/s at room temperature and atmospheric pressure employing vacuum evaporation at $69^{\circ}C$ and 30 kPa and hydrate-based concentration using $CH_4$, $CO_2$ and $SF_6$ as guest molecules. Operation energy consumption of VE-based concentration resulted in 47 kJ/mol, whereas those of hydrate-based concentration were 43, 32, and 28 kJ/mol for $CH_4$, $CO_2$ and $SF_6$ hydrates, respectively. We observe that hydrate-based concentration can a competitive option for dissolved ions recovery from energy consumption standpoint. However, the selection of guest gas is very critical, since it accordingly determines the hydration number, the hydrate formation energy, gas compression energy, etc. The selection of guest gas, separation of concentrated brine and water phases, and the enhancement of hydrate formation rate are the key factors for the commercialization of hydrated-based technology for concentrating dissolved ions.

Evaluation of Hydrate Inhibition Performance of Water-soluble Polymers using Torque Measurement and Differential Scanning Calorimeter (토크 측정과 시차주사열량계를 이용한 수용성 고분자 화합물의 하이드레이트 저해 성능 평가)

  • Shin, Kyuchul;Park, Juwoon;Kim, Jakyung;Kim, Hyunho;Lee, Yohan;Seo, Yongwon;Seo, Yutaek
    • Korean Chemical Engineering Research
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    • v.52 no.6
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    • pp.814-820
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    • 2014
  • In this work, hydrate inhibition performance of water-soluble polymers including pyrrolidone, caprolactam, acrylamide types were evaluated using torque measurement and high pressure differential scanning calorimeter (HP ${\mu}$-DSC). The obtained experimental results suggest that the studied polymers represent the kinetic hydrate inhibition (KHI) performance. 0.5 wt% polyvinylcaprolactam (PVCap) solution shows the hydrate onset time of 34.4 min and subcooling temperature of 15.9 K, which is better KHI performance than that of pure water - hydrate onset time of 12.3 min and subcooling temperature of 6.0 K. 0.5 wt% polyvinylpyrrolidone (PVP) solution shows the hydrate onset time of 27.6 min and the subcooling temperature of 13.2 K while polyacrylamide-co-acrylic acid partial sodium salt (PAM-co-AA) solution shows less KHI performance than PVP solution at both 0.5 and 5.0 wt%. However, PAM-co-AA solution shows slow growth rate and low hydrate amount than PVCap. In addition to hydrate onset and growth condition, torque change with time was investigated as one of KHI evaluation methods. 0.5 wt% PVCap solution shows the lowest average torque of 6.4 N cm and 0.5 wt% PAM-co-AA solution shows the average torque of 7.2 N cm. For 0.5 wt% PVP solution, it increases 11.5 N cm and 5.0 wt% PAM-co-AA solution shows the maximum average torque of 13.4 N cm, which is similar to the average torque of pure water, 15.2 N cm. Judging from the experimental results obtained by both an autoclave and a HP ${\mu}$-DSC, the PVCap solution shows the best performance among the KHIs in terms of delaying hydrate nucleation. From these results, it can be concluded that the torque change with time is useful to identify the flow ability of tested solution, and the further research on the inhibition of hydrate formation can be approached in various aspects using a HP ${\mu}$-DSC.

Effect of Submucosal Midazolam on Percutaneous Saturation Percentage of Oxygen ($SpO_2$), End-tidal Carbon Dioxide ($EtCO_2$) and Physiologic Response When Combined with Chloral Hydrate, Hydroxyzine and Nitrous Oxide Sedation (구강 점막 하 주입 Midazolam과 경구 투여한 Chloral Hydrate의 용량에 따른 산소 포화도 및 생징후 변화에 대한 비교 연구)

  • Yu, Ji-Hye;Kim, Yun-Hee;Jung, Sang-Hyuk;Baek, Kwang-Woo
    • Journal of The Korean Dental Society of Anesthesiology
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    • v.6 no.2 s.11
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    • pp.89-97
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    • 2006
  • Background: The aim of this study was to examine the difference of $SpO_2$, PR, $EtCO_2$, RR with submucosal injection of midazolam to oral chloral hydrate and hydroxyzine for pediatric patients Methods: Thirty two sedation cases were performed in this study. Patients were randomly classified into one group taking oral CH (60 mg/kg). hydroxyzine (1 mg/kg) and submucosal injection of midazolam (0.1 mg/kg) and the other group recieving oral CH (50 mg/kg), hydroxyzine (1 mg/kg) and submucosal injection of midazolam (0.2 mg/kg). For evaluating the depth of sedation. data including saturation percentage of oxygen ($SpO_2$), pulse rate (PR), end-tidal carbon dioxide ($EtCO_2$), respiratory rate (RR) and the behavior scale were checked every 2 minutes and were collected for only 40 minutes from the beginning of treatment and were analyzed using Two independent sample T-test. Results: Analysis showed no significant difference in the mean $SpO_2$, PR, $EtCO_2$, RR during sedation between two groups (P > 0.05). The values of $SpO_2$, PR, $EtCO_2$ and RR for both groups remained within the normal values. Conclusions: The results of this present study indicate that combination of oral CH, hydroxyzine, nitrous oxide gas inhalation and submucosal injection of midazolam improved the sedation quality without compromising safety.

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The Study of Crystal Growth for Carbon Dioxide Hydrate ($CO_2$ 하이드레이트 결정 성장 연구)

  • Kim, Soo-Min;Lee, Hyun-Ju;Lee, Yoon-Seok;Lee, Eun-Kyoung;Kim, Yang-Do
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.06a
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    • pp.709-709
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    • 2009
  • 지구 온난화의 주요한 원인인 $CO_2$ 가스 저감을 위한 많은 연구가 현재 수행중이며, 하이드레이트 형성원리를 이용한 $CO_2$ 분리 및 회수에 대한 연구가 보고되고 있다. 하이드레이트 형성에 있어 결정성장 거동에 관한 연구는 $CO_2$ 하이드레이트 형성 메커니즘을 규명하는데 기초자료를 제공할 것으로 사료된다. 본 연구에서는 274.1K의 정온 조건에 서 반회분식 교반 반응기를 이용하여 1.7MPa에서 3.0MPa으로 압력 조건을 바꾸면서 $CO_2$ 하이드레이트를 형성시켰다. 실험에 공급된 기체의 조성은 $CO_2$ (99.999%)이다. 실험 관측은 광학현미경(Nikon, SMZ 1000)에 장착된 CCD카메라(Nikon DS-5M/Fi1/2M-U2)에 의하여 이루어 졌다. 하이드레이트 형성 및 해리 과정을 CCD카메라로 촬영하고 시간에 따른 온도와 압력의 변화를 기록하여 핵생성 시간, 성장 속도, 성장 거동을 관찰하였다. 실험에 적용되는 압력에 따라서 하이드레이트 성장형태와 성장속도에서 매우 큰 차이를 보이는 것을 확인하였다.

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