• Title/Summary/Keyword: Clathrate

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Study on entrapping behavior of gas mixtures into hydroquinone clathrate (hydroquinone의 혼합기체 포집 거동 특성분석)

  • Choi, Kijong;Lee, Yongjae;Yoon, Jiho;Lee, Jongwon
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.06a
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    • pp.220-220
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    • 2010
  • clathrate compound란 호스트 분자가 수소 결합에 의하여 3차원 골격구조를 만들고, 이 격자 내부의 동공으로 저분자량의 기체 게스트 분자가 포집되며 형성되는 고체 결정 화합물이다. 현재까지 다양한 호스트 분자가 clathrate 화합물을 형성하는 것으로 보고되어 있으며, 이 중 유기물인 hydroquinone 역시 clathrate compound를 형성할 수 있는 것으로 알려져 있다. clathrate compound는 작은 고체 부피 내부에 막대한 양의 기체 분자를 저장할 수 있는 특성을 지니고 있기 때문에, 에너지 가스의 저장/수송이나 혼합 가스의 선택적 분리와 같은 다양한 응용을 위한 연구가 활발히 진행되고 있다. 본 연구에서는 clathrate compound를 형성하는 유기 호스트 분자인 hydroquinone을 이용하여 다양한 기체분자들에 대한 포집 거동을 파악하였다. 순수 기체로는 $N_2$, $H_2$, $CO_2$, $CH_4$의 4종류를 가지고 고압 반응기에서 50bar의 압력, 상온에서의 반응 조건으로 반응을 시켰다. 이렇게 형성된 반응 샘플들은 clathrate 형성 여부(기체의 포집 여부)를 확인하기 위하여 x-ray 회절을 통한 고체 결정 구조 분석을 수행하였다. 또한 순수 기체 이외에 다양한 비율(20%, 40%, 60%, 80%)의 조성을 갖는 $CO_2+N_2$ 혼합가스를 이용하여 clathrate compound의 형성과 조성 분석을 수행하였는데, x-ray 회절 분석과 13C 고체 NMR 분석을 통해 미세 구조 분석 연구를 수행하였고, Raman분석을 통하여 그 조성을 확인하였다. 본 연구에서 얻어진 결과는 기체의 저장/수송이나 혼합 가스의 선택적 분리와 같은 응용 분야에서 중요한 정보를 제공할 수 있을 것으로 기대된다.

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The Study on Cooling Characterics of TMA Clathrate with Ethanol (에탄올을 첨가한 TMA 포접화합물의 냉각특성에 대한 연구)

  • 김창오;김진흥;정낙규;김석현
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.14 no.8
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    • pp.634-640
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    • 2002
  • The purpose of this study is to investigate the propriety of TMA clathrate as a cold storage medium. Particularly, this is to examine the extent of subcooling improvement when the additives is added to the TMA clathrate, because water used for cold storage ma terial has low phase change temperature and subcooling. This study has been analyzed and compared pure water with TMA 30 wt% clathrate how phase change temperature, subcooling and specific heat in the various concentrations are changed. This results prove low phase change temperature and subcooling control effect when the ethanol is added to the TMA 30 wt% clathrate than the TMA 30 wt% clathrate. In addition, it results low specific heat when there is added to the TMA 30 wt% clathrate over 0.5 wt% ethanol in the cold heat source temperature under $-7^{\circ}C$. The other side, it results high specific heat when the ethanol is added in it at the cold heat source temperature under $-5^{\circ}C$. Therefore, it is found that the additive must be controlled by available solution limit and study for new additive must be lasted to know its effect.

The Study on Improvement in Subcooling of TMA Clathrate for PCM in Ice Storage System (빙축열시스템 PCM용 TMA-포접화합물의 과냉도 개선에 대한 연구)

  • Kim, J.H.;Chung, N.K.;Kim, C.O.
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.1663-1666
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    • 2003
  • TMA clathrate that is used by PCM of ice storage system in this research creates hydrate crystallization at higher temperature than pure water, and application is expected as PCM because having comparative big dormant temperature without phase separation phenomenon. In case this research uses TMA clathrate by PCM, choose admixture by purpose to control or remove subcooling of TMA clathrate and evaluated experimentally. Subcooling is improved and can expect contraction of freezing machine running time and increase of coefficient of performance as that add admixture to TMA clathrate conclusively. Also, may supply thermal storage system that apply low temperature potential heat thermal storage material that subcooling is improved more extensively laying stress on medium size building and small size building, can expect allowance through localization of ice storage system.

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Spectroscopic Analysis on Hydroquinone Clathrates for an Application to Storage/Recovery of Olefin Compounds (올레핀 저장/회수 기술 응용을 위한 하이드로퀴논 크러스레이트의 분광학적 분석 연구)

  • Lee, Jong-Won;Pratik, Dotel;Kang, Seong-Pil
    • Transactions of the Korean hydrogen and new energy society
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    • v.24 no.5
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    • pp.437-443
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    • 2013
  • Clathrate samples, using hydroquinone as a host and ethylene or propylene as a possible guest, were prepared and analyzed by means of spectroscopic measurements. Obtained results showed that ethylene can form clathrate compounds with hydroquinone at 4.0MPa and room temperature, while propylene cannot form clathrate compounds. Different formation behaviors of these two olefin compounds can be applied to a clathrate-based storage/recovery of ethylene in a selective way, and can provide useful information on the cavity size of the formed clathrate compounds.

A Study on the Cooling Characteristics and Subcooling Improvement of TMA-Water Clathrate Compound (TMA-물계 포접화합물의 냉각특성과 과냉각 개선에 대한 연구)

  • Park, Seul-Hyun;Kim, Chang-Oh
    • Journal of the Korean Solar Energy Society
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    • v.34 no.6
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    • pp.85-92
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    • 2014
  • This study carried out experimental on the cooling characteristics of clathrate compound including TMA(Tri-Methyl-Amine ; $(CH_3)_3N$) as a low temperature latent heat storage material. And additive was used for subcooling improvement of TMA-water clathrate compound. The conclusion of above study is as following ; TMA 25wt%-water clathrate compound is shown stable phase change and low subcooling degree. The subcooling was improved in the case ethanol($CH_3CH_2OH$) 0.5wt% is added to TMA 25wt%-water clathrate compound.

Lattice Contraction Behavior Occurring in Ionic Clathrate Hydrate (이온성 크러스레이트 하이드레이트의 격자 수축 거동)

  • Kwon, Minchul;Cha, Minjun;Shin, Kyuchul;Lee, Huen
    • 한국신재생에너지학회:학술대회논문집
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    • 2011.05a
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    • pp.150.2-150.2
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    • 2011
  • Unlike non-ionic clathrate hydrates stably formed by van der Waals interaction between a guest molecule and a surrounding host framework, ionic clathrate hydrates are stabilized by ionic interaction between an ionic guest molecule and the host water-framework. Here, we firstly described the stable entrapment of the superoxide ions in ${\gamma}$-irradiated $Me_4NOH+O_2$ hydrate. Owing to peculiar direct guest-guest ionic interaction, the lattice structure of ${\gamma}$-irradiated $Me_4NOH+O_2$ hydrate shows significant change of lattice contraction behavior even at relatively high temperature(120K). Particularly, we note that ionic-induced dimensional change is much greater than thermal-induced change. Such findings are expected to provide useful information for a better understanding of unrevealed nature of clathrate hydrate fields.

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A Basic Study on Thermal Properties of TMA Clathrate with Additives (첨가제를 포함한 TMA포접화합물의 열물성에 관한 기초적 연구)

  • 고광옥;정낙규;김진홍
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.13 no.11
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    • pp.1097-1105
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    • 2001
  • The purpose of this study is to investigate the propriety of TMA clathrate as a cold storage medium. Particularly, this is to examine the extent of subcooling improvement when the additives are added to the TMA clathrate, because water used cold storage material has low phase change temperature and subcooling. This study has been analysed and compared with TMA 30 wt% clathrate how phase change temperature, subcooling and specific heat in the various concentrations are changed. This results view to be improved phase change temperature and subcooling of TMA 30 wt% as a cold storage medium, when it had some additive. Additional1y, it is found that the additive must be controlled under available solution limit and study for new additive must be lasted to know its effect.

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The Effects of an Additive on the Thermal Properties of a Clathrate Compound (IV) - The Case of TMA Clathrate Compound with Surfactant - (포접화합물의 열물성에 미치는 첨가제의 효과 (IV) - TMA 물계 포접화합물에 계면활성제를 첨가한 경우 -)

  • Chung Nak Kyu;Kim Jin Heung;Kim Chang Oh
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.16 no.12
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    • pp.1212-1217
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    • 2004
  • This study investigated the improvement effect of a small portion of surfactant on the supercooling and the phase change temperature of TMA 30 wt% clathrate compound when surfactant is added to the clathrate compound. The experiments are carried out under various conditions; the concentration of additive ranges between 0.08~0.12 wt% and the temperature of heat source ranges between -8 and -6$^{\circ}C$. The experimental results show that the phase change temperature with the surfactant of 0.1 wt% is lower by 1$^{\circ}C$ than TMA 30 wt% and the supercooling is reduced by 1$0^{\circ}C$.

A Study on Cooling Characteristic of TMA-Water Clathrate Compound for Low Temperature Latent Heat Storage (저온잠열저장을 위한 TMA-물계 포접화합물의 냉각특성에 대한 연구)

  • Kim, Chang-Oh;Kim, Jin-Heung;Chung, Nak-Kyu
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.2471-2475
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    • 2007
  • Clathrate compound is the material that host in hydrogen bond forms cage and guest is included into it and combined. Crystallization of hydrate is generated at higher temperature than that of ice from pure water. And physical properties according to temperature are stable and congruent melting phenomenon is occurred without phase separation. But clathrate compound still had supercooling problem occurred in the course of phase change and supercooling should be minimized because it affects efficiency of equipment very much. Therefore, various studies on additives to restrain this or heat storage methods are needed. In this study was investigated the cooling characteristics of the TMA-water clathrate compound including TMA (Tri-methyl-amine, $(CH_3)_3N)$ of 20${\sim}$25 wt% as a low temperature latent heat storage material. And ethanol$(CH_3CH_2OH)$ was added and its cooling characteristics were studied experimentally to restrain supercooling of TMA-water clathrate compound.

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The Effects of an Additive on the Thermal Properties of a Clathrate Compound (III) - The Case of TMA Clathrate Compound with Acetone - (포접화합물의 열물성에 미치는 첨가제의 효과 (III) - TMA 물계 포접화합물에 Acetone을 첨가한 경우 -)

  • Kim Jin Heung;Chung Nak Kyu;Kim Suk Hyun;Kim Chang Oh;Kang Seung Hyeon
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.16 no.12
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    • pp.1183-1189
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    • 2004
  • An experimental investigation is conducted to measure phase change temperature and supercooling when acetone is added to TMA 30 wt% clathrate during cooling process in heat source. Also rate of volume change is investigated when acetone is added to TMA 30 wt% clathrate during the cooling process in heat source -8$^{\circ}C$. The results show that phase change temperature is about 4.5~5.5$^{\circ}C$ when acetone is added to TMA 30 wt% clathrate during the cooling process for heat sink temperature of -6, -7$^{\circ}C$ and -8$^{\circ}C$. Supercooling is repressed about 2~1$0^{\circ}C$ when 0.08 wt% acetone is added to it and rate of volume change is decreased about 2.9% when 0.1 wt% acetone is added for the heat sink temperature of -8$^{\circ}C$.