• Title, Summary, Keyword: Hydrogen

Search Result 10,941, Processing Time 0.064 seconds

THE NUMERICAL SIMULATION OF HYDROGEN DIFFUSION FOR THE HYDROGEN LEAKAGE IN TUNNEL (터널 내 수소연료 자동차의 수소 누설로 인한 수소 확산에 대한 수치해석 연구)

  • Ahn, Hyuk-Jin;Jung, Jae-Hyuk;Hur, Nahm-Keon;Lee, Moon-Kyu;Yong, Gee-Joong
    • Journal of computational fluids engineering
    • /
    • v.15 no.2
    • /
    • pp.47-54
    • /
    • 2010
  • In the present study, a numerical simulation for the diffusion of hydrogen leakage of FCV(Fuel Cell Vehicle) in a tunnel was performed to aid the assessment of risk in case of leakage accident. The temporal and spatial distributions of the hydrogen concentration around FCV are predicted from the present numerical analyses. Flammable region of 4-74% and explosive region of 18-59% hydrogen by volume was identified from the present results. Factors influencing the diffusion of the hydrogen jet were examined to evaluate the effectiveness of tunnel ventilation system for relieving the accumulation of the leaked hydrogen gas. The distribution of the concentration of the leaked hydrogen for various cases can be used as a database in various applications for the hydrogen safety.

Implantation of portable hydrogen alarm system based on palladium coated single mode optical fiber sensor (팔라듐이 코팅된 단일모드 광섬유 센서를 이용한 수소 경보 시스템 구현)

  • Mun, Nam-Il;Yang, Byung-Cheol;Kim, Kwang-Taek;Kim, Tae-Un
    • Journal of Sensor Science and Technology
    • /
    • v.18 no.4
    • /
    • pp.269-273
    • /
    • 2009
  • In this paper, a study on a portable hydrogen alarm system based on the palladium coated single mode fiber sensor has been reported. The fabricated hydrogen sensor exhibited 0.14 dB, 0.41 dB and 0.54 dB optical intensity variation when it was exposed by the nitrogen and hydrogen mixed gas containing 0.5 %, 1 % and 4 % of the hydrogen concentration, respectively. The fabricated sensor exhibited 20 second of response time and 120 second of recovery time for 4 % hydrogen containing gas. The fiber optics layout and software algorithm for detection of hydrogen leakage have been presented. The implanted portable hydrogen alarm system successfully generated an alarm signal when a 4 % hydrogen containing gas was leaked out.

A Performance Study of Portable Hydrogen Storage Tank (휴대용 수소 저장체 성능 특성 연구)

  • Park, Joon-Ho;Hwang, Yong-Sheen;Jee, Sang-Hoon;Kim, Sung-Han;Cha, Suk-Won
    • 한국신재생에너지학회:학술대회논문집
    • /
    • /
    • pp.315-318
    • /
    • 2009
  • Hydrogen is the ideal candidate as an alternative energy carrier, so many hydrogen storage methods are investigated. The hydrogen storage method using metal hydride is good candidate as energy sources for portable devices because hydrogen-storage as metal hydride shows large volumetric storage density. In this study, we investigated the variations of hydrogen charging/discharging performance of metal hydride tanks at different temperature conditions. We charged metal hydride tanks with hydrogen in low temperature because of the exothermic reactions of hydrogen absorption while we discharged in high temperature to provide sufficient heat because of the endothermic reactions of desorption. In addition, we investigated the difference of hydrogen charging/discharging performance between two tanks having different sizes.

  • PDF

Hydrogen Impurities Analysis From Proton Exchange Membrane Hydrogen Production (양자교환막을 이용하여 생산된 수소의 불순물 분석)

  • Lee, Taeckhong;Kim, Taewan;Park, Taesung;Choi, Woonsun;Kim, Hongyoul;Lee, Hongki
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.24 no.4
    • /
    • pp.288-294
    • /
    • 2013
  • This gas analysis data come from the hydrogen which is produced by proton exchange membrane. Main impurities of hydrogen are methane, oxygen, nitrogen, carbon monoxide, and carbon dioxide. The concentration of impurities is ranged between 0.0191 to $315{\mu}mol/mol$ for each impurity. Methane contamination is believed from the electrode reaction between carbon doped electrode and produced hydrogen. Nitrogen contamination should take place the sampling process error, not from PEM hydrogen Production system.

Proposal and Analysis of Hydrogen Mitigation System Guiding Hydrogen in Containment Building

  • Park, Kweonha;Lee, Khor Chong
    • Journal of the Korean Society of Marine Engineering
    • /
    • v.39 no.5
    • /
    • pp.516-521
    • /
    • 2015
  • This study is about a hydrogen mitigation system in a containment building like an offshore or a nuclear plant. A hydrogen explosion is possibly happened after condensation of steam if hydrogen releases with steam in a containment buildings. Passive autocatalytic recombiner is the one of the measures, but the performance of this equipment is not sure because the distribution of hydrogen is very irregular and is not predicted correctly. This study proposes a new approach for improving the hydrogen removing performance with hydrogen-guiding property. The steam is simulated and analysed. The results show that the shallow air containment reduced over 55% of the released hydrogen and the deep air containment type reduces over 80% of released hydrogen.

Investigation of the Hydrogen Storage Mechanism of Expanded Graphite by Measuring Electrical Resistance Changes

  • Im, Ji-Sun;Jang, Seung-Soon;Lee, Young-Seak
    • Bulletin of the Korean Chemical Society
    • /
    • v.33 no.9
    • /
    • pp.3033-3038
    • /
    • 2012
  • The hydrogen storage mechanism of graphite was studied by measuring the electrical resistance change. Graphite was expanded and activated to allow for an easy hydrogen molecule approach and to enlarge the adsorption sites. A vanadium catalyst was simultaneously introduced on the graphite during the activation process. The hydrogen storage increased due to the effects of expansion, activation, and the catalyst. In addition, the electrical resistance of the prepared samples was measured during hydrogen molecule adsorption to investigate the hydrogen adsorption mechanism. It was found that the electrical resistance changed as a result of the easy hydrogen molecule approach, as well as of the adsorption process and the catalyst. It was also notable that the catalyst improved not only the hydrogen storage capacity but also the speed of hydrogen storage based on the response time. The hydrogen storage mechanism is suggested based on the effects of expansion, activation, and the catalyst.

Local Structure Study of Liquid Phase Ethylene Glycol and 1,3-propanediol through Density Functional Theory

  • Nam, Seungsoo;Sim, Eunji
    • Proceeding of EDISON Challenge
    • /
    • /
    • pp.140-146
    • /
    • 2016
  • Using density functional Theory, we studied local structure of liquid ethylene glycol and 1,3-propanediol. For both liquid, making intramolecular hydrogen bonding is not preferred, because relative energy between with and without intramolecular hydrogen bond is only -1.95kcal/mol, which is far less than intermolecular hydrogen bonding energy, about -7.5kcal/mol. Also, hydrogen bond induce polarization of hydroxyl group and make $2^{nd}$ hydrogen bond more stronger. This effect was small in intramolecular hydrogen bond of ethylene glycol. When considering energy per hydrogen bond, making only one intermolecular hydrogen bond for ethylene glycol pair is energetically favored, while two intermolecular hydrogen bond can be formed in 1,3-propanediol pair.

  • PDF

An Experimental Study on the Sensor Response at Hydrogen Leakage in a Residential Fuel Cell System (가정용 연료전지 시스템 내부 수소 누출 시 센서 응답 특성에 관한 연구)

  • Kim, Young-Doo;Shin, Dong-Hoon;Chung, Tae-Yong;Nam, Jin-Hyun;Kim, Young-Gyu;Lee, Jung-Woon
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.20 no.5
    • /
    • pp.378-383
    • /
    • 2009
  • Hydrogen is the primary fuel in fuel cell systems. Because of high inflammation and explosion possibility of hydrogen, fuel cell systems require safety measures to prevent hydrogen hazard upon leakage. In this study, a model enclosure was made by referring to a commercial residential fuel cell system and hydrogen leakage experiments and computational simulations were conducted therein. Hydrogen was injected into the cavity through leakage holes located at the bottom while its flow rate was precisely controlled using MFC. The transient sensor signals from hydrogen sensors installed inside the enclosure were recorded and analyzed. The hydrogen sensor signals showed different delay times depending on their position relative to a leakage point, which indicated that hydrogen generally moves upward and accumulates at the upper region of a closed cavity. The inflammable regions with hydrogen concentration over 4% LEL were observed to locate near the leakage hole initially, and broaden towards the upper cavity region afterward. The simulation result showed that detection time at the hydrogen sensor was similar to the pattern of experimental results. However, the maximum concentration of hydrogen had a gap between experiment and simulation at detect point due to measurement errors and reaction rate.

Hydrogen adsorption properties of multi-walled carbon nanotubes (Multi-wall 탄소나노튜브의 수소 저장 특성)

  • Hwang, J.Y.;Lee, S.H.;Sim, K.S.;Kim, J.W.
    • Transactions of the Korean hydrogen and new energy society
    • /
    • v.12 no.1
    • /
    • pp.65-73
    • /
    • 2001
  • Carbon nanotubes were prepared by catalytic decomposition of $CH_4$ using Ni-MgO catalyst at various temperatures. $H_2$ effect on crystallinity and morphology during the synthesis of carbon nanotubes was investigated. The crystallinity and morphology were characterized by SEM, TEM, XRD, TGA, and Raman spectroscopy. In addition, the hydrogen adsorption properties were evaluated by PCT measurement in a hydrogen pressure range between 1 and 120 bar. The optimal synthesis temperature of carbon nanotubes was elevated in the presence of $H_2$, although significant difference of carbon nanotube morphology was not found. It is believed that hydrogen served as self-cleaner mops the amorphous carbon on the catalyst surface. It is proved that the carbon nanotubes have multi-walled structure, short length with a outer diameter of 20 ~40nm and open tips after elimination of the catalyst. The amount of hydrogen adsorbed in carbon nanotubes is increased as the pressure of hydrogen is increased and reaches 1.3 wt % under the hydrogen pressure of 120 bar at room temperature.

  • PDF